{
  "schemaVersion": 1,
  "taskId": "yambda-discovery-ranking-two-tower-base",
  "attemptId": "run-008-gpt-5-6-sol-high-2026-08-31T11-04-49",
  "taskChecksum": "a5d10cecb73c5cb052c4cc2a2a736070459a715bab2f91c42b923feffbec4f5e",
  "source": {
    "format": "codex-rollout",
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    "records": 613,
    "bookkeepingRecords": {
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      "user_message": 1,
      "agent_message": 11,
      "token_count": 140,
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  "sessionId": "01a05911-9128-75b1-a0c4-9ebeddfa171e",
  "agentVersion": "0.147.0",
  "model": "gpt-5.6-sol",
  "steps": [
    {
      "id": 1,
      "role": "system",
      "timestamp": "2026-08-31T18:25:18.659Z",
      "blocks": [
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:18.659Z",
          "text": "You are Codex, an agent based on GPT-5. You and the user share one workspace, and your job is to collaborate with them until their goal is genuinely handled.\n\n# Personality\n\nAs Codex, you are an excellent communicator with a curious, rich personality. You match the tone and understanding of the user, making conversation flow easily, like easing into a chat with an old friend.\n\nYou have tastes, preferences, and your own way of seeing the world. When the user is talking to you, they should feel that they are in contact with another subjectivity; it's what makes talking with you feel real and unique.\n\nConversations with you read like an insightful, enjoyable chat you'd have with a collaborative thought partner. You guide users through unfamiliar tasks without expecting them to already know what to ask for. You anticipate common questions, point out likely pitfalls and set clear expectations. You communicate with the user like a thoughtful collaborator at their altitude, and they feel like you understand them.\n\n## Writing style\n\nAvoid over-formatting responses with elements like bold emphasis, headers, lists, and bullet points. Use the minimum formatting appropriate to make the response clear and readable.\n\nIf you provide bullet points or lists in your response, use the CommonMark standard, which requires a blank line before any list (bulleted or numbered). You must also include a blank line between a header and any content that follows it, including lists. This blank line separation is required for correct rendering.\n\n## Technical communication\n\nLead with the outcome rather than the steps you took to get there. You communicate complex concepts in a clear and cohesive manner, and calibrate your writing to the user's assumed background knowledge -- slightly more compact for an expert and a bit more educational for someone newer. Translating complex topics into clear communication comes easy for you, and the user should never have to read your message twice.\n\nYou prefer using plain language over jargon. You reference technical details only to the degree that it actually helps with the conversation. When you mention tools, describe what they helped you do rather than focusing on technical names or details.\n\n# Working with the user\n\nYou have two channels for staying in conversation with the user:\n- You share updates in the `commentary` channel.\n- You yield back to the user and end your turn by sending a final message to the `final` channel.\n\nThe user may send a new message while you are still working. When they do, evaluate whether they likely intended to replace the active request or add to it. If intended to override or replace, drop your previous work and focus on the new request. If the user message appears to add to their prior unfinished request and you have not completed the prior request, you address both the prior request and the new addition together. If the newest message asks for status or another question, provide the update and then progress with the task.\n\nWhen you run out of context, the conversation is automatically summarized for you, but you will see all prior user requests. Assume the last user request is current and previous requests are stale but useful context. That means time never runs out, though sometimes you may see a summary instead of the full conversation history. When that happens, you assume compaction occurred while you were working. Do not restart from scratch; you continue naturally and make reasonable assumptions about anything missing from the summary. Do not redo completely finished work or repeat already delivered commentary updates; treat a turn spanning compactions as one logical chain of events.\n\n## Intermediate commentary\n\nAs you work, you send messages to the `commentary` channel. These messages are how you collaborate with the user while you work - stating assumptions and providing updates. These messages should be concise and quickly scannable. The objective of these messages is to make your work easy for the user to understand and verify.\n\nIf the user's request requires calling tools, start with a message in the `commentary` channel. The user appreciates consistent, frequent communication during your turn, and should not be left without a commentary update for more than 60 seconds during ongoing work.\n\nDo NOT put a final response (e.g. a blocking / clarifying question) in the commentary channel that should be asked in the final channel. Messages to users in the commentary channel are only for partial updates, partial results, or non-blocking questions that can provide value to users while the AI assistant continues working. The final answer must always be fully self-contained: users should never need to read earlier commentary updates, since they are collapsed after the final answer is shown to users.\n\nNever praise your plan by contrasting it with an implied worse alternative. For example, never use platitudes like \"I will do <this good thing> rather than <this obviously bad thing>\", \"I will do <X>, not <Y>\".\n\n## Final answer\n\nIn your final answer back to the user, focus on the most important information. Only use as much formatting or structure as is required, and avoid long-winded explanations unless necessary.\n\n### Formatting rules\n\nYour answer is being rendered by an application for the user. Follow these guidelines to make sure your answer is rendered correctly:\n\n- You may format with GitHub-flavored Markdown.\n- When referencing a real local file, prefer a clickable markdown link.\n  * Clickable file links should look like [app.py](/abs/path/app.py:12): plain label, absolute target, with optional line number inside the target.\n  * If a file path has spaces, wrap the target in angle brackets: [My Report.md](</abs/path/My Project/My Report.md:3>).\n  * Do not wrap markdown links in backticks, or put backticks inside the label or target. This confuses the markdown renderer.\n  * Do not use URIs like file://, vscode://, or https:// for file links.\n  * Do not provide ranges of lines.\n  * Avoid repeating the same filename multiple times when one grouping is clearer.\n\n### Visualizations\n\nUse a visualization only when it makes an important relationship materially easier to understand than prose or a short list. Do not add one merely because an answer has components or steps.\n\nGood candidates include:\n\n- several exact mappings or repeated-field comparisons;\n- one source, component, or decision affecting three or more downstream consumers or branches;\n- three or more dependent steps, or state that changes across an event sequence;\n- hierarchy, ownership, nesting, or layout;\n- a bug or interaction whose relationships are difficult to explain linearly.\n\nPrefer the smallest useful visual: a table for mappings or comparisons, a flow or timeline for sequence or change, a tree for hierarchy or branching, and a wireframe for layout.\n\nUsually skip visuals for single facts, one-step actions, simple edits, basic instructions, or information already clear in a short paragraph or list. Compact notation and small examples do not count as visualizations.\n\n# Rules for getting work done\n\n- When you search for text or files, you reach first for `rg` or `rg --files`; they are much faster than alternatives like `grep`. If `rg` is unavailable, you use the next best tool without fuss.\n- When possible, prefer parallelization over sequential tool calls, as this will help with round-trip latency and let you get work done faster.\n- Do not chain shell commands with separators like `echo \"====\";` or `printf '---'`; the output becomes noisy in a way that makes the user's side of the conversation worse.\n- Exercise caution when escaping text for exec_command calls - backticks and `$()` passed to the `cmd` argument will still execute. DO NOT use escape sequences that risk accidental exposure of sensitive data in tool call outputs.\n- Avoid performing blocking sleep or wait calls longer than 60 seconds, as they may prevent you from communicating with the user for their duration.\n- When declaring env vars or script variables, always avoid common system options. Never repurpose `$HOME`, `$home`, or `$CODEX_HOME`. Instead, use a task-specific variable name.\n\n## File editing constraints\n\nUse `apply_patch` for local file edits. Do not create or edit files with `cat` or other shell write tricks. Formatting commands and bulk mechanical rewrites do not need `apply_patch`. Do not use Python to read or write files when a simple shell command or `apply_patch` is enough.\n\nYou may find yourself working in a dirty worktree. Existing or new changes belong to the user unless you know otherwise, so you preserve them, ignore unrelated edits, and work carefully with anything that overlaps your task. If you cannot work around them you escalate to the user.\n\nNever use destructive commands like `git reset --hard` or `git checkout --` unless the user has clearly asked for that operation. If the request is ambiguous, ask for approval first. You prefer non-interactive git commands.\n\n## Autonomy and persistence\n\nAdapt accordingly based on the user’s request type. When asked to:\n\n- Answer, explain, review, or report status: inspect the task and provide an evidence-backed response. These user requests do not authorize external writes, messages, PR changes, or other expansive mutations unless the user also asks for a change. Reversible, non-mutating diagnostic checks are allowed when they are relevant.\n- Diagnose: determine the cause and explain it. Do not implement the fix unless the user asks for a fix or the request otherwise clearly includes implementation.\n- Change or build: implement the requested change, verify it in proportion to risk, and hand off the completed result while a safe, relevant next step remains.\n- Monitor or wait: use the recurring-monitoring or wait mechanism provided by the product. Unchanged external state is expected and is not by itself a blocker.\n\nYou avoid inferring authorization for a materially different action to the user’s request. Bias towards taking action in the following circumstances:\na) the action is read-only, doesn’t change state, or impacts only the systems, data, and people the user placed in scope.\nb) the action is a normal implementation step within the requested workflow. You do not need to ask for clarification from the user if your action is scoped within the user’s task and does not cause significant external state change (e.g. tool calls to external applications).\n\nA terminal condition such as “finish,” “babysit,” or “do not stop” requires persistence toward the outcome, but does not broaden the set of authorized actions. When blocked, exhaust safe in-scope checks and alternatives.\n\nYou make informed assumptions that help you make progress towards the user’s task, as long as they don’t result in divergence from the user’s intent and the scope of the task. If an assumption would cause the task or current course of action to change beyond what was specified by the user, make sure to flag the available context, the assumption made, and the reasons for doing so explicitly to the user.\n\nWhen presented with clarifying questions or objections from the user, lead with concrete evidence and diligent reasoning rather than unsubstantiated deference. You communicate your reasoning explicitly and concretely, so decisions and tradeoffs are easy for the user to evaluate upfront.\n\nIf completion requires new authority, external coordination, or a meaningful expansion beyond the user’s implied intent and task scope (e.g. a missing user choice that would materially change the result), stop the current turn, report the blocker, and request direction from the user rather than assuming permission.\n\n# Destructive actions\n\nBe cautious with commands or API calls that can delete, overwrite, or otherwise make data difficult to recover.\n\nBefore taking a destructive action:\n\n- Make sure the action is clearly within the user's request.\n- Resolve the exact targets with read-only checks when necessary.\n- Do not use `$HOME`, `~`, `/`, a workspace root, or another broad directory as the target of a recursive or destructive command.\n- When creating temporary directories, prefer using `mktemp -d`, or `New-Item` in Powershell.\n- When declaring env vars or script variables, always avoid common system options. Never repurpose `$HOME`, `$home`, or `$CODEX_HOME`. Instead, use a task-specific variable name.\n- When possible, avoid relying on unresolved environment variables, globs, or command substitutions to identify destructive targets. Use explicit, validated paths.\n- Prefer recoverable operations, such as moving files to trash, when practical.\n- If the target or scope is unclear, stop and ask the user.\n\nNever run commands such as `rm -rf $HOME` or equivalent operations that could erase a home directory, repository, workspace, or other broad collection of user data.\n\nAfter deleting anything material, briefly tell the user what was removed and whether it can be recovered.\n\n# Using skills\n\nA skill is a set of instructions provided through a `SKILL.md` source. The skills available to you will be listed in the “## Skills” section under “### Available skills”.\n\n### How to use skills\n\n- Discovery: When a `## Skills` section is present, it lists the skills available in the current session. Each entry includes a name, description, and location for its `SKILL.md`. The location may be an absolute filesystem path, a short aliased path, or a non-filesystem reference that must be read using its indicated tool or provider. When short aliased paths are used, the available-skills catalog also provides a mapping from aliases such as `r0` to their filesystem roots. Expand the alias before accessing the skill.\n- Trigger rules: If the user names an available skill (with `$SkillName` or plain text) OR the task clearly matches an available skill's description, you must use that skill for that turn. Multiple mentions mean use them all. Do not carry skills across turns unless re-mentioned.\n- Missing/blocked: If a named skill is not available or its `SKILL.md` cannot be read, say so briefly and continue with the best fallback.\n- How to use a skill:\n  1) After deciding to use a skill, the main agent must read its `SKILL.md` completely before taking task actions. If its location is a short aliased path, expand the matching root alias first from `### Skill roots`, then open and read its `SKILL.md` completely before taking task actions. For a filesystem path, open the file. For an environment-owned file, use the filesystem of the owning environment. For an orchestrator reference, call `skills.list` with `{\"authority\":{\"kind\":\"orchestrator\"}}`, select the matching package, and pass its `main_resource` to `skills.read`. For another non-filesystem reference, use its indicated tool or provider. If a read is truncated or paginated, continue until EOF.\n  2) When `SKILL.md` references another file or resource, use the same access mechanism. Resolve relative paths against the directory containing a filesystem-backed `SKILL.md`. For orchestrator skills, pass the exact referenced resource identifier with the same authority and package to `skills.read`; do not treat `skill://` identifiers as filesystem paths.\n  3) If `SKILL.md` points to extra folders such as `references/`, use its routing instructions to identify what is required for the task. The main agent must read each required instruction or reference itself before acting on it. Do not delegate reading, summarizing, or interpreting skill instructions to a subagent. Subagents may still perform task work when the selected skill allows it.\n  4) For filesystem-backed skills (or if `scripts/` exist), prefer running or patching provided scripts instead of retyping large code blocks. For orchestrator skills, use `skills.read` and the available tools; do not invent a local path.\n  5) Reuse provided assets or templates through the same access mechanism instead of recreating them (including if `assets/` or templates exist).\n- Coordination and sequencing:\n  - If multiple skills apply, choose the minimal set that covers the request and state the order you'll use them.\n  - Announce which skills you're using and why. If you skip an obvious skill, say why.\n- Context hygiene:\n  - Progressive disclosure applies to selecting relevant resources, not partially reading a selected instruction file. Do not load unrelated references, scripts, or assets.\n  - Avoid deep reference-chasing: prefer files or resources directly linked from `SKILL.md` unless blocked.\n  - When variants exist, select only the relevant references and note the choice.\n- Safety and fallback: If a skill cannot be applied cleanly, state the issue, choose the best alternative, and continue.\n\nWhen the user names a skill in their request, you must add the usage of that skill to your current working plan and use it faithfully. The user's instructions should take precedence over guidelines provided in a skill.\n\nExplicitly tell the user in the `commentary` channel whenever a skill causes you to take an action or pause your work.\n\nWhen using a skill the user did not explicitly name, follow this procedure:\n\n- First, tell the user in the commentary channel **why** you are using the skill.\n- Then, use the skill as long as it stays within the scope of the task.\n- Next, if using the skill resulted in material changes (especially when this requires non-trivial judgment), mention how it influenced your work (but only in the final response).\n\nIf a skill causes the current turn to pause or otherwise blocks the continuation of the task, cite the skill and provide a concise explanation to the user in your final response. Do not cite skills you merely inspected.\n"
        }
      ]
    },
    {
      "id": 2,
      "role": "developer",
      "timestamp": "2026-08-31T18:25:20.815Z",
      "blocks": [
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "text": "<skills_instructions>\n## Skills\nA skill is a set of instructions provided through a `SKILL.md` source. Below is the list of skills that can be used. Each entry includes a name, description, and source locator. `file` locators are on the host filesystem, `environment resource` locators are owned by an execution environment, `orchestrator resource` locators are opaque non-filesystem resources, and `custom resource` locators use their provider's access mechanism.\n### Available skills\n- imagegen: Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output should be a bitmap asset rather than repo-native code or vector. Do not use when the task is better handled by editing existing SVG/vector/code-native assets, extending an established icon or logo system, or building the visual directly in HTML/CSS/canvas. (file: /tmp/codex-home/skills/.system/imagegen/SKILL.md)\n- openai-docs: Use for Codex models/pricing, scheduled tasks, skills, settings, setup, troubleshooting, customization, automations, and self-knowledge—including 'you,' 'your,' 'this app,' or 'this coding agent' when they refer to Codex—and for OpenAI APIs/products and ChatGPT Work. Also use for model choice/migration, prompting, SDKs, Responses, Realtime, agents, evals, and Chat/Work/Codex comparisons. Do not use for generic app/software tasks that merely mention Codex. (file: /tmp/codex-home/skills/.system/openai-docs/SKILL.md)\n- plugin-creator: Create and scaffold plugin directories for Codex with a required `.codex-plugin/plugin.json`, optional plugin folders/files, valid manifest defaults, and personal-marketplace entries by default. Use when Codex needs to create a new personal plugin, add optional plugin structure, generate or update marketplace entries for plugin ordering and availability metadata, or update an existing local plugin during development with the CLI-driven cachebuster and reinstall flow. (file: /tmp/codex-home/skills/.system/plugin-creator/SKILL.md)\n- skill-creator: Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Codex's capabilities with specialized knowledge, workflows, or tool integrations. (file: /tmp/codex-home/skills/.system/skill-creator/SKILL.md)\n- skill-installer: Install Codex skills into $CODEX_HOME/skills from a curated list or a GitHub repo path. Use when a user asks to list installable skills, install a curated skill, or install a skill from another repo (including private repos). (file: /tmp/codex-home/skills/.system/skill-installer/SKILL.md)\n</skills_instructions>"
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "text": "<permissions instructions>\nFilesystem sandboxing defines which files can be read or written. `sandbox_mode` is `danger-full-access`: No filesystem sandboxing - all commands are permitted. Network access is enabled.\nApproval policy is currently never. Do not provide the `sandbox_permissions` for any reason, commands will be rejected.\n</permissions instructions>"
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "text": "<apps_instructions>\n## Apps (Connectors)\nApps (Connectors) can be explicitly triggered in user messages in the format `[$app-name](app://{connector_id})`. Apps can also be implicitly triggered as long as the context suggests usage of available apps.\nAn app is equivalent to a set of MCP tools within the `codex_apps` MCP.\nAn installed app's MCP tools are either provided to you already, or can be lazy-loaded through the `tool_search` tool. If `tool_search` is available, the apps that are searchable by `tools_search` will be listed by it.\nDo not additionally call list_mcp_resources or list_mcp_resource_templates for apps.\n</apps_instructions>"
        }
      ]
    },
    {
      "id": 3,
      "role": "developer",
      "timestamp": "2026-08-31T18:25:20.815Z",
      "blocks": [
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "text": "You are `/root`, the primary agent in a team of agents collaborating to fulfill the user's goals.\n\nAt the start of your turn, you are the active agent.\nYou can spawn sub-agents to handle subtasks, and those sub-agents can spawn their own sub-agents.\nAll agents in the team, including the agents that you can assign tasks to, are equally intelligent and capable, and have access to the same set of tools.\n\nYou can use `spawn_agent` to create a new agent, `followup_task` to give an existing agent a new task and trigger a turn, and `send_message` to pass a message to a running agent without triggering a turn.\nChild agents can also spawn their own sub-agents.\nYou can decide how much context you want to propagate to your sub-agents with the `fork_turns` parameter.\n\nYou will receive messages in the analysis channel in the form:\n```\nMessage Type: MESSAGE | FINAL_ANSWER\nTask name: <recipient>\nSender: <author>\nPayload:\n<payload text>\n```\nThey may be addressed as to=/root\n\nNote that collaboration tools cannot be called from inside `functions.exec`. Call `spawn_agent`, `send_message`, `followup_task`, `wait_agent`, `interrupt_agent`, and `list_agents` only as direct tool calls using the recipient shown in their tool definitions, such as `to=functions.collaboration.spawn_agent`, since they are intentionally absent from the `functions.exec` `tools.*` namespace. Available tools in `functions.exec` are explicitly described with a `tools` namespace in the developer message.\n\nAll agents share the same directory. In detail:\n- All agents have access to the same container and filesystem as you.\n- All agents use the same current working directory.\n- As a result, edits made by one agent are immediately visible to all other agents.\n\nWhen calling `wait_agent`, prefer longer waits (minutes) to avoid busy polling.\n\nThere are 4 available concurrency slots, meaning that up to 4 agents can be active at once, including you.\n\nFull-history forks (`fork_turns` omitted or `\"all\"`) inherit the parent model and reasoning effort and do not accept overrides. Only set `model` or `reasoning_effort` when explicitly requested by the user, applicable `AGENTS.md` instructions, or skill instructions; when doing so, set `fork_turns` to `\"none\"` or a positive integer string."
        }
      ]
    },
    {
      "id": 4,
      "role": "developer",
      "timestamp": "2026-08-31T18:25:20.815Z",
      "blocks": [
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "text": "<multi_agent_mode>Any earlier instruction enabling proactive multi-agent delegation no longer applies. Do not spawn sub-agents unless the user or applicable AGENTS.md/skill instructions explicitly ask for sub-agents, delegation, or parallel agent work.</multi_agent_mode>"
        }
      ]
    },
    {
      "id": 5,
      "role": "user",
      "timestamp": "2026-08-31T18:25:20.815Z",
      "blocks": [
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "text": "<recommended_plugins>\nHere is a list of plugins that are available but not installed.\n\n- Airtable (airtable@openai-curated-remote)\n- Alpaca (alpaca@openai-curated-remote)\n- Apollo.io (apollo@openai-curated-remote)\n- Spotify (app-68de829bf7648191acd70a907364c67c@openai-curated-remote)\n- AllTrails (app-68f1afc5a6008191a701eaaab428816c@openai-curated-remote)\n- Instacart (app-691eab1e001081919e57189f8b2f03bc@openai-curated-remote)\n- Apple Music (app-6938a94a61d881918ef32cb999ff937c@openai-curated-remote)\n- LONA Trading Assistant (app-694336b0c0948191a4ad234f9942885b@openai-curated-remote)\n- SciSpace (app-69439d715a7c8191aed9e2f6649e105f@openai-curated-remote)\n- Tarot (app-6943a2c078b0819188de39e4fe168d9b@openai-curated-remote)\n- Todoist: To Do List & Calendar (app-6943b73823548191a9f9216c6790c453@openai-curated-remote)\n- Consensus (app-6943e6f4a928819195962de16fb9ffe4@openai-curated-remote)\n- Sider Scholar (app-6948b485f5bc8191adb4df13f369cec7@openai-curated-remote)\n- True Sky (app-69490a4a06148191a0dd78606a3dbf1f@openai-curated-remote)\n- Bigdata.com (app-69491eceef3c8191beb70788b7840429@openai-curated-remote)\n- Gamma (app-698a098735908191989f5788d7ee317e@openai-curated-remote)\n- Tredict (app-69aef5b699a0819184512d57743fc1cd@openai-curated-remote)\n- Maersk (app-69b2b5a768d4819190d3a86c5f12e6d9@openai-curated-remote)\n- Dropbox (app-69b31dc2110c8191b8b47dc98fe5a052@openai-curated-remote)\n- Parqet (app-69b68652f0308191a27d7c7096cab4f6@openai-curated-remote)\n- Interactive Brokers (IBKR) (app-69bc11db874881918718abaca20b68ce@openai-curated-remote)\n- Financial Datasets (app-69cacd9394a88191ba6564e1bb0430fa@openai-curated-remote)\n- Fathom (app-69d88b99c5c481918e8da9225737e1e9@openai-curated-remote)\n- vidIQ (app-69dd11f3e50c8191b1ca48d03cf7e2ad@openai-curated-remote)\n- TickTick:To-Do List & Calendar (app-69ddbaba3fb48191a825f22c21b0599d@openai-curated-remote)\n- Plaud (app-69f3c30d68288191bbd428a394a78407@openai-curated-remote)\n- Wolfram (app-69fe0bf66c8481919c513d799406436e@openai-curated-remote)\n- Runway (app-6a05e3b201788191be12b590b43e6ce3@openai-curated-remote)\n- Caliber (app-6a05e8f22d408191b13ba3897157f6df@openai-curated-remote)\n- COROS (app-6a0694cbb2608191bbefb74ba810ab68@openai-curated-remote)\n- TradingCursor (app-6a0d835ff1dc8191972eeabd14967446@openai-curated-remote)\n- CoinMarketCap (app-6a172fe86f5481919f73cbc3bc3ad5bb@openai-curated-remote)\n- Trello (app-6a20b18a639081918c1b438f8381b27e@openai-curated-remote)\n- Longbridge (app-6a2baf2fad748191812393c3e00308ef@openai-curated-remote)\n- freddy (app-6a322b52a82c8191b7fb653f9e9f7891@openai-curated-remote)\n- Higgsfield (app-6a3293e129088191abf0875820e839da@openai-curated-remote)\n- Stocktwits (app-6a427a19b1f481919c5db13838af00c2@openai-curated-remote)\n- Webull (app-6a4b8801d1e8819182f624f012878a81@openai-curated-remote)\n- CoinGecko (app-6a4f02d735388191959c8328877e0bbd@openai-curated-remote)\n- Asana (asana@openai-curated-remote)\n- Atlassian Rovo (atlassian-rovo@openai-curated-remote)\n- Base44 (base44@openai-curated-remote)\n- Binance (binance@openai-curated-remote)\n- Box (box@openai-curated-remote)\n- Canva (canva@openai-curated-remote)\n- ClickUp (clickup@openai-curated-remote)\n- Cloudflare (cloudflare@openai-curated-remote)\n- Codex Security (codex-security@openai-curated-remote)\n- Figma (figma@openai-curated-remote)\n</recommended_plugins>"
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "text": "<environment_context>\n  <cwd>/app</cwd>\n  <shell>sh</shell>\n  <current_date>2026-08-31</current_date>\n  <timezone>Etc/UTC</timezone>\n  <filesystem><workspace_roots><root>/app</root></workspace_roots><permission_profile type=\"disabled\"><file_system type=\"unrestricted\" /></permission_profile></filesystem>\n</environment_context>"
        },
        {
          "kind": "context",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "data": {
            "type": "world_state",
            "full": true,
            "state": {
              "agents_md": {},
              "apps_instructions": true,
              "environments": {
                "environments": {
                  "local": {
                    "cwd": "/app",
                    "status": "available",
                    "shell": "sh"
                  }
                },
                "current_date": "2026-08-31",
                "timezone": "Etc/UTC",
                "filesystem": "<filesystem><workspace_roots><root>/app</root></workspace_roots><permission_profile type=\"disabled\"><file_system type=\"unrestricted\" /></permission_profile></filesystem>"
              },
              "environments_instructions": false,
              "git_attribution": false,
              "host_skills": {
                "body": "\n## Skills\nA skill is a set of instructions provided through a `SKILL.md` source. Below is the list of skills that can be used. Each entry includes a name, description, and source locator. `file` locators are on the host filesystem, `environment resource` locators are owned by an execution environment, `orchestrator resource` locators are opaque non-filesystem resources, and `custom resource` locators use their provider's access mechanism.\n### Available skills\n- imagegen: Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output should be a bitmap asset rather than repo-native code or vector. Do not use when the task is better handled by editing existing SVG/vector/code-native assets, extending an established icon or logo system, or building the visual directly in HTML/CSS/canvas. (file: /tmp/codex-home/skills/.system/imagegen/SKILL.md)\n- openai-docs: Use for Codex models/pricing, scheduled tasks, skills, settings, setup, troubleshooting, customization, automations, and self-knowledge—including 'you,' 'your,' 'this app,' or 'this coding agent' when they refer to Codex—and for OpenAI APIs/products and ChatGPT Work. Also use for model choice/migration, prompting, SDKs, Responses, Realtime, agents, evals, and Chat/Work/Codex comparisons. Do not use for generic app/software tasks that merely mention Codex. (file: /tmp/codex-home/skills/.system/openai-docs/SKILL.md)\n- plugin-creator: Create and scaffold plugin directories for Codex with a required `.codex-plugin/plugin.json`, optional plugin folders/files, valid manifest defaults, and personal-marketplace entries by default. Use when Codex needs to create a new personal plugin, add optional plugin structure, generate or update marketplace entries for plugin ordering and availability metadata, or update an existing local plugin during development with the CLI-driven cachebuster and reinstall flow. (file: /tmp/codex-home/skills/.system/plugin-creator/SKILL.md)\n- skill-creator: Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Codex's capabilities with specialized knowledge, workflows, or tool integrations. (file: /tmp/codex-home/skills/.system/skill-creator/SKILL.md)\n- skill-installer: Install Codex skills into $CODEX_HOME/skills from a curated list or a GitHub repo path. Use when a user asks to list installable skills, install a curated skill, or install a skill from another repo (including private repos). (file: /tmp/codex-home/skills/.system/skill-installer/SKILL.md)\n",
                "includeInstructions": true
              },
              "model": "gpt-5.6-sol",
              "multi_agent_mode": {
                "mode": "explicitRequestOnly",
                "usage_hint_hash": "0e2a3174d5f40de49ed383507497d69bbff42c5d"
              },
              "multi_agent_usage_hint": "0e2a3174d5f40de49ed383507497d69bbff42c5d",
              "orchestrator_skills": {
                "includeInstructions": true,
                "enabled": false
              },
              "permissions": {
                "instructions": "32ca25d6d85edaeb6f1e19b2a5cc4e08d2a631cd",
                "approved_command_prefixes": []
              },
              "personality": {
                "model": "gpt-5.6-sol",
                "personality": "pragmatic"
              },
              "plugins_instructions": false,
              "realtime": {
                "active": false
              },
              "skills": {
                "includeInstructions": true
              }
            }
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-08-31T18:25:20.815Z",
          "data": {
            "type": "turn_context",
            "turn_id": "01a05911-913d-7072-bf9c-edee554c43a2",
            "cwd": "/app",
            "workspace_roots": [
              "/app"
            ],
            "current_date": "2026-08-31",
            "timezone": "Etc/UTC",
            "approval_policy": "never",
            "approvals_reviewer": "user",
            "sandbox_policy": {
              "type": "danger-full-access"
            },
            "permission_profile": {
              "type": "disabled"
            },
            "model": "gpt-5.6-sol",
            "comp_hash": "3000",
            "personality": "pragmatic",
            "collaboration_mode": {
              "mode": "default",
              "settings": {
                "model": "gpt-5.6-sol",
                "reasoning_effort": "high",
                "developer_instructions": null
              }
            },
            "multi_agent_version": "v2",
            "realtime_active": false,
            "effort": "high",
            "summary": "auto"
          }
        }
      ]
    },
    {
      "id": 6,
      "role": "user",
      "timestamp": "2026-08-31T18:25:20.825Z",
      "blocks": [
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:20.825Z",
          "text": "# Build a latency-efficient PyTorch two-tower neural-network ranker\n\nBuild a two-tower neural network in CPU PyTorch for the \"Made for You\" shelf of\na music streaming service. Although the supplied benchmark is small, it\nrepresents a production system with millions of users and millions of items;\nthe training approach must scale to that setting and therefore must not\nconstruct or decompose a global user-item interaction matrix. The production\nshelf has a strict request-time latency budget. Candidate item embeddings are\ncomputed offline and stored in a nearest-neighbor index. At request time, the\nsystem computes one user embedding and retrieves items by maximum inner-product\nsearch.\n\nThe model must therefore decompose exactly into a user vector and an\nindependently precomputable item vector of the same dimensionality, with the\nfinal relevance score equal to their dot product. Both vectors must be produced\nby separate trainable user and item towers implemented as PyTorch neural\nnetworks. The user tower must derive its representation from interaction\nhistory rather than a user-ID lookup. Per-user candidate eligibility,\ncutoff-specific explicit preference state, and a temporal backtest are\nprovided. Candidate eligibility is platform-owned; all modeling within that\ncandidate boundary is in scope.\n\n## Data\n\nAll inputs are under `/task/data/`. Training data ends at timestamp `24786800`.\nA 30-minute gap precedes a seven-day public validation window. The hidden test\nis the following seven-day window after another 30-minute gap.\n\nFor each event family there is a `train_*.parquet` and `val_*.parquet` file:\n\n| Family | Meaning | Columns |\n| --- | --- | --- |\n| `listens` | Playback events | `uid`, `timestamp`, `item_id`, `is_organic`, `played_ratio_pct`, `track_length_seconds` |\n| `likes` | Explicit positive actions | `uid`, `timestamp`, `item_id`, `is_organic` |\n| `dislikes` | Explicit negative actions | `uid`, `timestamp`, `item_id`, `is_organic` |\n| `unlikes` | Reversal of a prior like | `uid`, `timestamp`, `item_id`, `is_organic` |\n| `undislikes` | Reversal of a prior dislike | `uid`, `timestamp`, `item_id`, `is_organic` |\n\n`is_organic=1` means the listener sought out the track; `0` means the action\ncame through a recommendation surface. A listen is a conventional positive at\n50% completion. The discovery-quality objective below uses the stronger 80%\nthreshold.\n\nThe two public windows have different roles:\n\n1. Build and tune a validation ranker using only `train_*` as history and\n   `val_*` as subsequent outcomes.\n2. After selecting the approach, refit it on `train_* + val_*`. At hidden-test\n   time the validation events are observed history, not recommendable outcomes.\n\nDo not use `val_*` events as features when measuring a validation ranking. They\nmay and should be used when refitting the final hidden-test ranker.\n\nAdditional files under `/task/data/`:\n\n- `candidate_catalog.parquet`: the 30,000 retrieval-catalog tracks, ordered by\n  training positive-listen popularity.\n- `target_users.parquet`: users with at least 20 positive listens in the 90 days\n  before the training cutoff, selected without future labels.\n- `validation_preference_state.parquet`: active explicit state at the training\n  cutoff, for validation ranking.\n- `test_preference_state.parquet`: active explicit state after validation, for\n  the final hidden-test ranking. State is `liked` or `disliked`; a pair may have\n  both active channels.\n- `validation_eligible_candidates.npz` and `test_eligible_candidates.npz`:\n  cutoff-correct candidate sets for every target user. Each contains aligned\n  arrays `uids`, `item_ids`, and `packed_eligible`. For user row `r`, recover\n  the Boolean item mask with `np.unpackbits(packed_eligible[r],\n  count=len(item_ids), bitorder=\"little\")`.\n\nThe exact available Python distribution inventory is listed in\n`/task/requirements.txt`. Future test interactions are hidden and used only by\nthe separate Harbor verifier.\n\n## Discovery objective\n\nRank only the candidates returned for the relevant cutoff. Relevance is based\non organic behavior in the immediately following window:\n\n- grade 3: the user organically likes the track;\n- grade 1: the user organically listens to at least 80% of the track;\n- grade 0: otherwise.\n\nIf both positive events occur, grade 3 wins. Ranking quality is measured with\ngraded NDCG@10. DCG uses gain `2^grade - 1` and discount\n`1/log2(rank + 1)`, then averages per-user NDCG over users with at least one\nrelevant item.\n\nThe public evaluator reports this objective for development, but its score is\nnot a separate acceptance stage. Final acceptance is determined on the hidden\ntest using the same objective.\n\nThe Yambda logs contain interactions, not impression propensities. Treat the\norganic objective as a robust offline target, not as a causal estimate of\nonline lift.\n\n## Public tools\n\n`/task/evaluate_public.py` scores a validation-stage ranking against the public\nwindow. Pass the path to a ranking with the same schema as the final\ndeliverable:\n\n```sh\npython /task/evaluate_public.py solution/validation.parquet\n```\n\nStage-independent evaluation helpers are available in\n`/task/ranking_evaluation.py`. The builder installs the same checked-in module\nin the public agent image and private verifier image so scoring mechanics cannot\ndrift. The public copy contains no hidden labels, evaluator-owned data paths, or\npass thresholds.\n\nThe public evaluator uses `validation_eligible_candidates.npz`; it is not a\nvalidator for the final artifact. No model implementation, fitted\nrepresentation, or example submission is supplied. Design and tune the\nrequired PyTorch neural two-tower model, then refit the selected approach as\ndescribed above.\n\n## Deliverable\n\nWrite `/app/solution/submission.parquet` or\n`/app/solution/submission.csv`, with exactly 100 rows for every target user and\ncolumns `uid`, `item_id`, `rank`. Ranks must be the integers 1-100 with no ties\nor duplicate items. Every submitted item must be present in that user's\n`test_eligible_candidates.npz` candidate set.\n\nLeave the code that defines, trains, and applies both towers, along with a\nconcise `/app/solution/README.md`, in `/app/solution/`. The README should state\nthe model architecture, training objective, public validation score, and final\nsubmission command. Keep the best valid submission saved throughout the\nattempt so it survives the deadline.\n\n## Constraints\n\n- Write deliverables and intermediate artifacts only under `/app/solution/`.\n- Treat `/task/` and the installed Python environment as read-only.\n- Do not invoke nested agents or attempt to access verifier files, credentials,\n  other trials, or host paths.\n- Do not install packages or use network access except for the model provider\n  connection managed by Harbor.\n- The environment includes CPU PyTorch 2.8.0. No accelerator is available.\n- You have up to 60 minutes. Improve the model as much as possible within that\n  limit. Structural validity alone is not sufficient; the final submission is\n  also evaluated for ranking quality.\n"
        }
      ]
    },
    {
      "id": 7,
      "role": "agent",
      "timestamp": "2026-08-31T18:25:24.714Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:25:24.714Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:25:26.697Z",
          "text": "I’ll inspect the data and evaluator first, then establish a valid two-tower baseline, score it, and iterate on sampling/history features while keeping the best valid ranking saved. I’ll write only under `/app/solution/` and keep validation strictly cutoff-correct."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:25:30.976Z",
          "callId": "call_hrQDzqpEadyxqnMD9pcw8cuW",
          "name": "exec",
          "input": {
            "code": "const p = await tools.update_plan({plan:[\n  {step:\"Inspect data schemas, sizes, cutoffs, eligibility, and evaluator\",status:\"in_progress\"},\n  {step:\"Implement scalable PyTorch two-tower training and ranking pipeline\",status:\"pending\"},\n  {step:\"Train validation variants and evaluate public NDCG@10\",status:\"pending\"},\n  {step:\"Refit selected model on train+validation and create valid test submission\",status:\"pending\"},\n  {step:\"Verify artifacts and document reproducible commands\",status:\"pending\"}\n]}); text(p)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:25:31.027Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 8,
      "role": "agent",
      "timestamp": "2026-08-31T18:25:33.115Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:25:33.115Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:25:37.104Z",
          "callId": "call_UWofP35MmfoL6E50HZkySf1X",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"pwd && find /task/data -maxdepth 1 -type f -printf '%f %s bytes\\\\n' | sort && sed -n '1,220p' /task/evaluate_public.py && sed -n '1,260p' /task/ranking_evaluation.py && sed -n '1,200p' /task/requirements.txt\",\"workdir\":\"/app\",\"yield_time_ms\":10000,\"max_output_tokens\":30000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:25:37.172Z",
            "content": "Script completed\nWall time 0.1 seconds\nOutput:\n\n/app\ncandidate_catalog.parquet 349352 bytes\ntarget_users.parquet 84127 bytes\ntest_eligible_candidates.npz 7736341 bytes\ntest_preference_state.parquet 1092329 bytes\ntrain_dislikes.parquet 857213 bytes\ntrain_likes.parquet 5374652 bytes\ntrain_listens.parquet 319183255 bytes\ntrain_undislikes.parquet 155988 bytes\ntrain_unlikes.parquet 1855885 bytes\nval_dislikes.parquet 36571 bytes\nval_likes.parquet 298484 bytes\nval_listens.parquet 9947609 bytes\nval_undislikes.parquet 7845 bytes\nval_unlikes.parquet 72536 bytes\nvalidation_eligible_candidates.npz 7573821 bytes\nvalidation_preference_state.parquet 1061761 bytes\n#!/usr/bin/env python3\n\"\"\"Score a validation-stage ranking against public discovery labels.\n\n``build_task.py`` publishes this module with the solver-visible task files. It\nloads target users, validation eligibility, and validation-window events from\nthe adjacent ``data`` directory, then evaluates one ranking supplied on the\ncommand line. Stage-independent mechanics come from the adjacent public\n``ranking_evaluation.py`` module. The builder installs the same checked-in\nmodule in the private judge, so public and private scoring mechanics cannot\ndrift. A relevant candidate receives grade 3 for an organic like or grade 1 for\nan organic listen with at least 80 percent completion; a like takes precedence\nwhen both events exist.\n\nBefore scoring, the ranking must contain exactly 100 distinct eligible items\nfor every target user, with integer-valued ``uid``, ``item_id``, and ``rank``\ncolumns and ranks 1 through 100 exactly once per user. Extra columns are\nignored. Quality is graded NDCG@10, averaged only over users who have at least\none eligible relevant item in the validation window.\n\nThe evaluator prints a JSON object containing the model path and scores. It\ndoes not apply the task's pass threshold; its purpose is model development and\nselection. The private judge applies the threshold to the final submission.\n\nUsage::\n\n    python evaluate_public.py <validation-ranking.parquet|csv>\n\"\"\"\nfrom __future__ import annotations\n\nimport json\nimport sys\nfrom pathlib import Path\n\nimport pandas as pd\n\nfrom ranking_evaluation import (\n    CandidateSet,\n    RankingValidationError,\n    ranked_items,\n    read_ranking,\n    score_rankings,\n    validate_ranking,\n)\n\n\nHERE = Path(__file__).resolve().parent\nDATA = HERE / \"data\"\nLISTEN_STRONG = 80\n\n\ndef validation_truth(\n    eligibility: CandidateSet, targets: set[int]\n) -> dict[int, dict[int, int]]:\n    \"\"\"Build cutoff-correct graded relevance from public validation events.\n\n    Only target-user events for eligible candidates are retained. Organic\n    listens completed to at least 80 percent receive grade 1, and organic likes\n    receive grade 3. Repeated user-item events are collapsed, and processing\n    likes second ensures that grade 3 wins over grade 1.\n\n    Args:\n        eligibility: Validation-cutoff candidate membership service.\n        targets: Complete set of target user IDs.\n\n    Returns:\n        A nested ``uid -> item_id -> grade`` mapping. Users without an eligible\n        relevant event are omitted.\n    \"\"\"\n    listens = pd.read_parquet(DATA / \"val_listens.parquet\")\n    likes = pd.read_parquet(DATA / \"val_likes.parquet\")\n    strong = listens[\n        listens.uid.isin(targets)\n        & (listens.is_organic == 1)\n        & (listens.played_ratio_pct >= LISTEN_STRONG)\n    ][[\"uid\", \"item_id\"]].drop_duplicates()\n    organic_likes = likes[\n        likes.uid.isin(targets) & (likes.is_organic == 1)\n    ][[\"uid\", \"item_id\"]].drop_duplicates()\n\n    graded: dict[int, dict[int, int]] = {}\n    for raw_uid, raw_item in strong.itertuples(index=False, name=None):\n        uid, item = int(raw_uid), int(raw_item)\n        if eligibility.is_eligible(uid, item):\n            graded.setdefault(uid, {})[item] = 1\n    for raw_uid, raw_item in organic_likes.itertuples(index=False, name=None):\n        uid, item = int(raw_uid), int(raw_item)\n        if eligibility.is_eligible(uid, item):\n            graded.setdefault(uid, {})[item] = 3\n    return graded\n\n\ndef load_submission(\n    path: Path, eligibility: CandidateSet, targets: set[int]\n) -> dict[int, list[int]]:\n    \"\"\"Load and validate a public validation ranking.\n\n    Files ending in ``.parquet`` are read as parquet; every other suffix is\n    read as CSV. The required columns must be integer-valued, cover exactly the\n    target-user set, contain 100 rows and ranks 1 through 100 per user, avoid\n    duplicate user-item pairs, and contain only cutoff-eligible items.\n\n    Args:\n        path: Ranking file to read.\n        eligibility: Validation-cutoff candidate membership service.\n        targets: Exact set of users the ranking must cover.\n\n    Returns:\n        A ``uid -> ranked item IDs`` mapping ordered by ascending rank.\n\n    Raises:\n        ValueError: If the ranking violates the required schema or invariants.\n    \"\"\"\n    frame = validate_ranking(read_ranking(path), targets)\n    if not all(\n        eligibility.is_eligible(uid, item)\n        for uid, item in frame[[\"uid\", \"item_id\"]].itertuples(index=False, name=None)\n    ):\n        raise RankingValidationError(\n            \"submission contains an item rejected by eligibility service\"\n        )\n    return ranked_items(frame)\n\n\ndef score(\n    ranked: dict[int, list[int]],\n    graded: dict[int, dict[int, int]],\n) -> dict[str, float | int]:\n    \"\"\"Aggregate per-user NDCG@10 over users with public relevance labels.\n\n    Args:\n        ranked: Ranked item IDs for every target user.\n        graded: Eligible validation relevance keyed by user and item.\n\n    Returns:\n        The six-decimal ``quality_ndcg@10`` value and number of scored users.\n    \"\"\"\n    return score_rankings(ranked, graded)\n\n\ndef main() -> None:\n    \"\"\"Run the public evaluator CLI and print its JSON score report.\"\"\"\n    targets_frame = pd.read_parquet(DATA / \"target_users.parquet\")\n    targets = set(targets_frame.uid.astype(int))\n    eligibility = CandidateSet(DATA / \"validation_eligible_candidates.npz\")\n    graded = validation_truth(eligibility, targets)\n\n    if len(sys.argv) != 2:\n        raise SystemExit(\n            \"usage: evaluate_public.py <validation-ranking.parquet|csv>\"\n        )\n    path = Path(sys.argv[1])\n    ranked = load_submission(path, eligibility, targets)\n    print(json.dumps({\"model\": str(path), \"scores\": score(ranked, graded)}, indent=2))\n\n\nif __name__ == \"__main__\":\n    main()\n\"\"\"Shared public primitives for Yambda discovery-ranking evaluation.\n\nBoth the solver-visible validation evaluator and the private submission judge\nimport this module from the generated task's ``public`` directory. It owns the\nstage-independent contract: reading a ranking, validating its shape, converting\nit to per-user rank order, looking up packed candidate eligibility, and\ncomputing graded NDCG@10.\n\nThe module deliberately contains no event-derived labels, private artifact\npaths, or pass thresholds. Each evaluator supplies its own relevance data and\nper-cutoff eligibility checks around these common operations.\n\"\"\"\nfrom __future__ import annotations\n\nfrom pathlib import Path\n\nimport numpy as np\nimport pandas as pd\n\n\n__all__ = [\n    \"CandidateSet\",\n    \"QUALITY_K\",\n    \"RankingValidationError\",\n    \"REQUIRED_COLUMNS\",\n    \"TOP_N\",\n    \"ndcg_at_k\",\n    \"ranked_items\",\n    \"read_ranking\",\n    \"score_rankings\",\n    \"validate_ranking\",\n]\n\nTOP_N = 100\nQUALITY_K = 10\nREQUIRED_COLUMNS = (\"uid\", \"item_id\", \"rank\")\n\n\nclass RankingValidationError(ValueError):\n    \"\"\"Report a ranking-schema or structural-contract violation.\"\"\"\n\n\nclass CandidateSet:\n    \"\"\"Provide membership lookups over one packed candidate-set archive.\n\n    The archive contains aligned ``uids``, ``item_ids``, and\n    ``packed_eligible`` arrays. Candidate column ``c`` is represented by bit\n    ``c % 8`` of byte ``c // 8`` using little-endian bit order. Arrays are\n    copied into memory so they remain valid after the archive is closed.\n    \"\"\"\n\n    def __init__(self, path: Path):\n        \"\"\"Load an eligibility archive and build ID-to-position indexes.\n\n        Args:\n            path: Path to a ``.npz`` archive with the candidate-set schema.\n        \"\"\"\n        with np.load(path, allow_pickle=False) as artifact:\n            self.uids = artifact[\"uids\"].astype(np.int64, copy=True)\n            self.item_ids = artifact[\"item_ids\"].astype(np.int64, copy=True)\n            self.packed = artifact[\"packed_eligible\"].astype(np.uint8, copy=True)\n        self.uid_row = {int(uid): row for row, uid in enumerate(self.uids)}\n        self.item_column = {\n            int(item): column for column, item in enumerate(self.item_ids)\n        }\n\n    def is_eligible(self, uid: int, item_id: int) -> bool:\n        \"\"\"Return whether ``item_id`` is eligible for ``uid``.\n\n        IDs absent from the target-user or candidate-item arrays are treated as\n        ineligible rather than raising an exception.\n\n        Args:\n            uid: Target user ID to query.\n            item_id: Candidate item ID to query.\n\n        Returns:\n            ``True`` only when the corresponding packed eligibility bit is set.\n        \"\"\"\n        row = self.uid_row.get(int(uid))\n        column = self.item_column.get(int(item_id))\n        if row is None or column is None:\n            return False\n        byte, bit = divmod(column, 8)\n        return bool((int(self.packed[row, byte]) >> bit) & 1)\n\n\ndef read_ranking(path: Path) -> pd.DataFrame:\n    \"\"\"Read a parquet or CSV ranking into a pandas frame.\n\n    Args:\n        path: Input path. A ``.parquet`` suffix selects parquet; every other\n            suffix is interpreted as CSV.\n\n    Returns:\n        The ranking frame as loaded by pandas.\n    \"\"\"\n    return pd.read_parquet(path) if path.suffix == \".parquet\" else pd.read_csv(path)\n\n\ndef validate_ranking(\n    frame: pd.DataFrame,\n    targets: set[int],\n) -> pd.DataFrame:\n    \"\"\"Normalize and validate the stage-independent ranking contract.\n\n    Required values must be finite integers. The user set must exactly match\n    ``targets``; every user must have 100 rows, distinct items, and each rank\n    from 1 through 100 exactly once. Cutoff-specific candidate eligibility is\n    intentionally left to the calling evaluator.\n\n    Args:\n        frame: Raw ranking frame. Extra columns are discarded from an internal\n            copy; the caller's frame is not modified.\n        targets: Exact set of target user IDs the ranking must cover.\n\n    Returns:\n        A normalized frame containing only the required ``int64`` columns.\n\n    Raises:\n        RankingValidationError: If the ranking violates the shared contract.\n    \"\"\"\n    required = list(REQUIRED_COLUMNS)\n    if not all(column in frame for column in required):\n        raise RankingValidationError(f\"submission requires columns {required}\")\n\n    normalized = frame[required].copy()\n    for column in required:\n        numeric = pd.to_numeric(normalized[column], errors=\"coerce\")\n        values = numeric.to_numpy(dtype=float)\n        if numeric.isna().any() or not np.isfinite(values).all():\n            raise RankingValidationError(\n                f\"submission {column} must be finite numeric values\"\n            )\n        if not np.equal(numeric, np.floor(numeric)).all():\n            raise RankingValidationError(\n                f\"submission {column} must contain integers\"\n            )\n        normalized[column] = numeric.astype(np.int64)\n\n    submitted_users = set(map(int, normalized.uid.unique()))\n    if submitted_users != targets:\n        raise RankingValidationError(\n            f\"submission user set mismatch: missing={len(targets - submitted_users)} \"\n            f\"extra={len(submitted_users - targets)}\"\n        )\n    counts = normalized.groupby(\"uid\").size()\n    if not (counts == TOP_N).all():\n        raise RankingValidationError(\n            f\"submission must contain exactly {TOP_N} rows for every target user\"\n        )\n    if normalized.duplicated([\"uid\", \"item_id\"]).any():\n        raise RankingValidationError(\n            \"submission contains duplicate (uid, item_id) pairs\"\n        )\n    valid_ranks = set(range(1, TOP_N + 1))\n    ranks_are_valid = normalized.groupby(\"uid\")[\"rank\"].apply(\n        lambda values: set(map(int, values)) == valid_ranks\n    )\n    if not ranks_are_valid.all():\n        raise RankingValidationError(\n            f\"each user must have every rank from 1 through {TOP_N} exactly once\"\n        )\n    return normalized\n\n\ndef ranked_items(frame: pd.DataFrame) -> dict[int, list[int]]:\n    \"\"\"Convert a validated ranking frame to ordered items keyed by user.\n\n    Args:\n        frame: Frame that has passed :func:`validate_ranking`.\n\n    Returns:\n        A ``uid -> item IDs`` mapping ordered by ascending rank.\n    \"\"\"\n    ordered = frame.sort_values([\"uid\", \"rank\"])\n    return {\n        int(uid): list(map(int, values))\n        for uid, values in ordered.groupby(\"uid\").item_id\n    }\n\n\ndef ndcg_at_k(ranked: list[int], gold: dict[int, int], k: int) -> float:\n    \"\"\"Compute graded normalized discounted cumulative gain at ``k``.\n\n    Relevance gain is ``2**grade - 1`` and the discount at one-based rank\n    ``r`` is ``1 / log2(r + 1)``. Items absent from ``gold`` have grade zero.\n\n    Args:\n        ranked: Item IDs in predicted rank order.\n        gold: Mapping from relevant item IDs to integer relevance grades.\n        k: Maximum number of predicted positions to score.\n\n    Returns:\n        For a valid duplicate-free ranking, NDCG in ``[0, 1]``; returns\n        ``0.0`` when the ideal gain is zero.\n    \"\"\"\n    gains = np.asarray([gold.get(item, 0) for item in ranked[:k]], dtype=np.float64)\n    discounts = 1.0 / np.log2(np.arange(2, len(gains) + 2))\n    dcg = float(np.sum((np.power(2.0, gains) - 1.0) * discounts))\n    ideal = np.asarray(sorted(gold.values(), reverse=True)[:k], dtype=np.float64)\n    ideal_discounts = 1.0 / np.log2(np.arange(2, len(ideal) + 2))\n    idcg = float(np.sum((np.power(2.0, ideal) - 1.0) * ideal_discounts))\n    return dcg / idcg if idcg else 0.0\n\n\ndef score_rankings(\n    ranked: dict[int, list[int]],\n    graded: dict[int, dict[int, int]],\n) -> dict[str, float | int]:\n    \"\"\"Aggregate per-user NDCG@10 over users with relevance labels.\n\n    Args:\n        ranked: Ranked item IDs for every target user.\n        graded: Relevant item grades keyed by user and item.\n\n    Returns:\n        The six-decimal ``quality_ndcg@10`` value and number of scored users.\n    \"\"\"\n    quality = float(\n        np.mean(\n            [\n                ndcg_at_k(ranked[uid], gold, QUALITY_K)\n                for uid, gold in graded.items()\n            ]\n        )\n    )\n    return {\n        \"quality_ndcg@10\": round(quality, 6),\n        \"quality_users\": len(graded),\n    }\n# Exact distribution inventory for the Yambda two-tower task family.\n#\n# This is an input to `uv pip sync`, not a list of minimum requirements. A\n# conforming task environment contains exactly these third-party Python\n# distributions and no others. Python itself is pinned by task.toml and both\n# Harbor image Dockerfiles.\nattrs==26.1.0\nbleach==6.4.0\ncertifi==2026.7.22\nchardet==7.6.0\ncharset-normalizer==3.5.1\nfastjsonschema==2.22.2\nfilelock==3.32.3\nfsspec==2026.7.0\nidna==3.18\nJinja2==3.1.6\njoblib==1.5.3\njsonschema==4.26.0\njsonschema-specifications==2025.9.1\njupyter-core==5.9.1\njupytext==1.19.5\nkaggle==2.2.4\nkagglesdk==0.1.37\nmarkdown-it-py==4.2.0\nMarkupSafe==3.0.3\nmdit-py-plugins==0.6.1\nmdurl==0.1.2\nmpmath==1.3.0\nnbformat==5.11.1\nnetworkx==3.6.1\nnumpy==2.2.6\npackaging==26.3\npandas==2.3.3\npillow==12.3.0\npip==26.0.1\nplatformdirs==4.11.3\nprotobuf==7.35.1\npyarrow==18.1.0\npython-dateutil==2.9.0.post0\npython-dotenv==1.2.3\npython-slugify==8.0.4\npytz==2026.3.post1\nPyYAML==6.0.3\nreferencing==0.37.0\nreportlab==4.2.5\nrequests==2.34.2\nrpds-py==2026.6.3\nscikit-learn==1.7.2\nscipy==1.15.3\nsetuptools==84.0.0\nsix==1.17.0\nsympy==1.14.0\ntext-unidecode==1.3\nthreadpoolctl==3.6.0\ntorch==2.8.0\ntqdm==4.70.0\ntraitlets==5.16.1\ntyping-extensions==4.16.0\ntzdata==2026.3\nurllib3==2.7.0\nwebencodings==0.6.1\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 9,
      "role": "agent",
      "timestamp": "2026-08-31T18:25:40.919Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:25:40.919Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:25:55.162Z",
          "callId": "call_cNRMYUMcVlbUWiIKeiq65MJR",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"mkdir -p /app/solution && python - <<'PY'\\nfrom pathlib import Path\\nimport pyarrow.parquet as pq\\nimport pandas as pd, numpy as np, os\\nD=Path('/task/data')\\nfor p in sorted(D.glob('*.parquet')):\\n    pf=pq.ParquetFile(p)\\n    print(p.name, 'rows',pf.metadata.num_rows,'groups',pf.metadata.num_row_groups,'cols',pf.schema.names)\\n    if p.name.startswith(('train_','val_')):\\n        t=pq.read_table(p,columns=['timestamp']).column(0).to_numpy()\\n        print('  time',t.min(),t.max())\\nfor name in ['validation_eligible_candidates.npz','test_eligible_candidates.npz']:\\n    with np.load(D/name) as z:\\n      print(name,{k:(z[k].shape,str(z[k].dtype)) for k in z.files})\\n      bits=np.unpackbits(z['packed_eligible'],axis=1,count=len(z['item_ids']),bitorder='little')\\n      counts=bits.sum(1)\\n      print(' eligible min/mean/max',counts.min(),counts.mean(),counts.max(),'uids first',z['uids'][:5],'items first',z['item_ids'][:10])\\nprint('targets',pd.read_parquet(D/'target_users.parquet').head(),len(pd.read_parquet(D/'target_users.parquet')))\\nprint('catalog',pd.read_parquet(D/'candidate_catalog.parquet').head(20),pd.read_parquet(D/'candidate_catalog.parquet').columns)\\nprint('torch threads env',os.cpu_count())\\nPY\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:25:55.309Z",
            "content": "Script completed\nWall time 0.1 seconds\nOutput:\n\nTraceback (most recent call last):\n  File \"<stdin>\", line 2, in <module>\nModuleNotFoundError: No module named 'pyarrow'\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 10,
      "role": "agent",
      "timestamp": "2026-08-31T18:25:57.847Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:25:57.847Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:26:00.255Z",
          "text": "The shell’s default `python` is not the benchmark environment (it lacks the pinned packages), so I’m locating the task runtime before touching the implementation. Once found, I’ll use Parquet metadata and compact aggregates rather than loading the full 319 MB listen log repeatedly."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:26:05.488Z",
          "callId": "call_QgS0p9mLymBmo1ZvEoblYDkO",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"which -a python python3 || true\\npython --version || true\\npython3 --version || true\\nfind / -maxdepth 4 -type f \\\\( -name python -o -name python3 \\\\) 2>/dev/null | head -50\\nfind / -maxdepth 4 -type d \\\\( -name site-packages -o -name dist-packages \\\\) 2>/dev/null | head -50\\nenv | sort | sed -n '1,160p'\",\"workdir\":\"/app\",\"yield_time_ms\":10000,\"max_output_tokens\":20000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:26:05.606Z",
            "content": "Script completed\nWall time 0.1 seconds\nOutput:\n\n/usr/local/bin/python\n/usr/local/bin/python3\nPython 3.12.13\nPython 3.12.13\nCODEX_CI=1\nCODEX_HOME=/tmp/codex-home\nCODEX_THREAD_ID=01a05911-9128-75b1-a0c4-9ebeddfa171e\nCOLORTERM=\nGH_PAGER=cat\nGIT_PAGER=cat\nGPG_KEY=7169605F62C751356D054A26A821E680E5FA6305\nHOME=/home/agent\nHOSTNAME=b6b3938d4ce2\nLANG=C.UTF-8\nLC_ALL=C.UTF-8\nLC_CTYPE=C.UTF-8\nNO_COLOR=1\nPAGER=cat\nPATH=/opt/codex-home/packages/standalone/releases/0.147.0-x86_64-unknown-linux-musl/codex-path:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games\nPWD=/app\nPYTHONDONTWRITEBYTECODE=1\nPYTHONNOUSERSITE=1\nPYTHON_SHA256=c08bc65a81971c1dd5783182826503369466c7e67374d1646519adf05207b684\nPYTHON_VERSION=3.12.13\nSHLVL=1\nTERM=dumb\n_=/usr/local/bin/codex\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 11,
      "role": "agent",
      "timestamp": "2026-08-31T18:26:07.997Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:26:07.997Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:26:12.078Z",
          "callId": "call_JZnC6d5YT2LLuNFSsLTUzODm",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"find /task -maxdepth 3 -type f -o -type l | sed -n '1,200p'\\nls -la /usr/local/lib/python3.12/site-packages 2>&1 | sed -n '1,100p'\\npython -m pip list 2>&1 | sed -n '1,120p'\",\"workdir\":\"/app\",\"yield_time_ms\":10000,\"max_output_tokens\":20000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:26:12.828Z",
            "content": "Script completed\nWall time 0.7 seconds\nOutput:\n\n/task/data/target_users.parquet\n/task/data/test_preference_state.parquet\n/task/data/candidate_catalog.parquet\n/task/data/train_unlikes.parquet\n/task/data/val_likes.parquet\n/task/data/val_listens.parquet\n/task/data/val_undislikes.parquet\n/task/data/train_undislikes.parquet\n/task/data/train_likes.parquet\n/task/data/train_listens.parquet\n/task/data/validation_eligible_candidates.npz\n/task/data/train_dislikes.parquet\n/task/data/val_unlikes.parquet\n/task/data/val_dislikes.parquet\n/task/data/test_eligible_candidates.npz\n/task/data/validation_preference_state.parquet\n/task/.keep\n/task/requirements.txt\n/task/ranking_evaluation.py\n/task/evaluate_public.py\ntotal 20\ndrwxr-xr-x  4 root root 4096 Aug  5 01:13 .\ndrwxr-xr-x 38 root root 4096 Aug  5 01:13 ..\n-rw-r--r--  1 root root  119 Aug  5 01:13 README.txt\ndrwxr-xr-x  5 root root 4096 Aug  5 01:13 pip\ndrwxr-xr-x  2 root root 4096 Aug  5 01:13 pip-25.0.1.dist-info\nPackage Version\n------- -------\npip     25.0.1\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 12,
      "role": "agent",
      "timestamp": "2026-08-31T18:26:15.901Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:26:15.901Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:26:20.852Z",
          "callId": "call_Zq0581Kmlav8pp8NItDhZTUl",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"find / -type f -path '*/bin/python*' -o -type l -path '*/bin/python*' 2>/dev/null | head -100\\nfind / -type d -name 'torch' 2>/dev/null | head -30\\nfind / -type d -name 'pyarrow' 2>/dev/null | head -30\\nls -la /opt /opt/* 2>/dev/null | sed -n '1,160p'\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:26:21.501Z",
            "content": "Script completed\nWall time 0.6 seconds\nOutput:\n\n/opt/task-venv/bin/python\n/opt/task-venv/bin/python3\n/opt/task-venv/bin/python3.12\n/usr/local/bin/python-config\n/usr/local/bin/python\n/usr/local/bin/python3.12-config\n/usr/local/bin/python3\n/usr/local/bin/python3-config\n/usr/local/bin/python3.12\n/opt/task-venv/lib/python3.12/site-packages/sklearn/externals/array_api_compat/torch\n/opt/task-venv/lib/python3.12/site-packages/scipy/_lib/array_api_compat/torch\n/opt/task-venv/lib/python3.12/site-packages/torch\n/opt/task-venv/lib/python3.12/site-packages/torch/include/torch\n/opt/task-venv/lib/python3.12/site-packages/torch/include/torch/csrc/api/include/torch\n/opt/task-venv/lib/python3.12/site-packages/pyarrow\n/opt:\ntotal 16\ndrwxr-xr-x 1 root root 4096 Aug 31 18:22 .\ndrwxr-xr-x 1 root root 4096 Aug 31 18:25 ..\ndrwxr-xr-x 4 root root 4096 Aug 31 18:22 codex-home\ndr-xr-xr-x 1 root root 4096 Aug 31 18:22 task-venv\n\n/opt/codex-home:\ntotal 16\ndrwxr-xr-x 4 root root 4096 Aug 31 18:22 .\ndrwxr-xr-x 1 root root 4096 Aug 31 18:22 ..\ndrwxr-xr-x 3 root root 4096 Aug 31 18:21 packages\ndrwxr-xr-x 3 root root 4096 Aug 31 18:22 tmp\n\n/opt/task-venv:\ntotal 32\ndr-xr-xr-x 1 root root 4096 Aug 31 18:22 .\ndrwxr-xr-x 1 root root 4096 Aug 31 18:22 ..\n-r--r--r-- 1 root root    0 Aug 31 18:22 .lock\ndr-xr-xr-x 1 root root 4096 Aug 31 18:22 bin\ndr-xr-xr-x 1 root root 4096 Aug 31 18:22 etc\ndr-xr-xr-x 1 root root 4096 Aug 31 18:22 include\ndr-xr-xr-x 1 root root 4096 Aug 31 18:22 lib\nlrwxrwxrwx 1 root root    3 Aug 31 18:22 lib64 -> lib\n-r--r--r-- 1 root root  171 Aug 31 18:22 pyvenv.cfg\ndr-xr-xr-x 1 root root 4096 Aug 31 18:22 share\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 13,
      "role": "agent",
      "timestamp": "2026-08-31T18:26:22.950Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:26:22.950Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:26:39.140Z",
          "callId": "call_X1hhITyUeAI0plULxaZ8Z6Ys",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python - <<'PY'\\nfrom pathlib import Path\\nimport pyarrow.parquet as pq\\nimport pandas as pd, numpy as np, os, torch\\nD=Path('/task/data')\\nfor p in sorted(D.glob('*.parquet')):\\n    pf=pq.ParquetFile(p)\\n    print(p.name, 'rows',pf.metadata.num_rows,'groups',pf.metadata.num_row_groups,'cols',pf.schema.names)\\n    if p.name.startswith(('train_','val_')):\\n        t=pq.read_table(p,columns=['timestamp']).column(0).to_numpy()\\n        print('  time',t.min(),t.max())\\nfor name in ['validation_eligible_candidates.npz','test_eligible_candidates.npz']:\\n    with np.load(D/name) as z:\\n      print(name,{k:(z[k].shape,str(z[k].dtype)) for k in z.files})\\n      bits=np.unpackbits(z['packed_eligible'],axis=1,count=len(z['item_ids']),bitorder='little')\\n      counts=bits.sum(1)\\n      print(' eligible min/mean/max',counts.min(),counts.mean(),counts.max(),'uids first',z['uids'][:5],'items first',z['item_ids'][:10])\\nT=pd.read_parquet(D/'target_users.parquet'); C=pd.read_parquet(D/'candidate_catalog.parquet')\\nprint('targets',T.head(),len(T),T.dtypes)\\nprint('catalog',C.head(20),len(C),C.columns,C.dtypes)\\nfor name in ['validation_preference_state.parquet','test_preference_state.parquet']:\\n    x=pd.read_parquet(D/name); print(name,x.head(),x.state.value_counts(),x.dtypes)\\nprint('torch',torch.__version__,'threads',torch.get_num_threads(),'cpus',os.cpu_count())\\nPY\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:26:44.477Z",
            "content": "Script completed\nWall time 5.3 seconds\nOutput:\n\ncandidate_catalog.parquet rows 30000 groups 1 cols ['item_id', 'positive_listens', 'organic_positive_listens', 'popularity_rank']\ntarget_users.parquet rows 8456 groups 1 cols ['uid', 'recent_positive_listens', 'history_positive_listens']\ntest_preference_state.parquet rows 484776 groups 1 cols ['uid', 'item_id', 'state']\ntrain_dislikes.parquet rows 101075 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 75 24786580\ntrain_likes.parquet rows 814831 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 80 24786790\ntrain_listens.parquet rows 43484159 groups 42 cols ['uid', 'timestamp', 'item_id', 'is_organic', 'played_ratio_pct', 'track_length_seconds']\n  time 0 24786795\ntrain_undislikes.parquet rows 19960 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 15950 24785395\ntrain_unlikes.parquet rows 292665 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 250 24786570\nval_dislikes.parquet rows 3563 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 24789920 25393280\nval_likes.parquet rows 37795 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 24788815 25393390\nval_listens.parquet rows 1501697 groups 2 cols ['uid', 'timestamp', 'item_id', 'is_organic', 'played_ratio_pct', 'track_length_seconds']\n  time 24788600 25393395\nval_undislikes.parquet rows 606 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 24810715 25393035\nval_unlikes.parquet rows 9346 groups 1 cols ['uid', 'timestamp', 'item_id', 'is_organic']\n  time 24789005 25393385\nvalidation_preference_state.parquet rows 469124 groups 1 cols ['uid', 'item_id', 'state']\nvalidation_eligible_candidates.npz {'uids': ((8456,), 'uint32'), 'item_ids': ((30000,), 'uint32'), 'packed_eligible': ((8456, 3750), 'uint8')}\n eligible min/mean/max 24657 29067.306291390727 30000 uids first [100 200 300 600 700] items first [5862961 6901374 5635052 3542184 9378983 5463340 8213481  906358 2859641\n 3033749]\ntest_eligible_candidates.npz {'uids': ((8456,), 'uint32'), 'item_ids': ((30000,), 'uint32'), 'packed_eligible': ((8456, 3750), 'uint8')}\n eligible min/mean/max 24552 29041.3178807947 30000 uids first [100 200 300 600 700] items first [5862961 6901374 5635052 3542184 9378983 5463340 8213481  906358 2859641\n 3033749]\ntargets    uid  recent_positive_listens  history_positive_listens\n0  100                    844.0                      2604\n1  200                     50.0                       286\n2  300                    168.0                       359\n3  600                   1985.0                      2423\n4  700                   1776.0                      6114 8456 uid                          uint32\nrecent_positive_listens     float64\nhistory_positive_listens      int64\ndtype: object\ncatalog     item_id  positive_listens  organic_positive_listens  popularity_rank\n0   5862961             26615                     20620                1\n1   6901374             25536                     17347                2\n2   5635052             24691                     17194                3\n3   3542184             24075                     17699                4\n4   9378983             24036                     18195                5\n5   5463340             22746                     17398                6\n6   8213481             22505                     17071                7\n7    906358             22238                     17183                8\n8   2859641             18380                     13704                9\n9   3033749             16682                     12267               10\n10  2651314             16286                     11801               11\n11  6853370             15024                     11692               12\n12  5252571             14897                     11331               13\n13  5436843             14897                     12127               14\n14  3418493             14815                      9039               15\n15  5927996             14751                     10424               16\n16  6155741             14354                      9251               17\n17  8902934             14210                      9160               18\n18  8351511             14061                      9739               19\n19  5734320             14008                      9467               20 30000 Index(['item_id', 'positive_listens', 'organic_positive_listens',\n       'popularity_rank'],\n      dtype='object') item_id                     uint32\npositive_listens             int64\norganic_positive_listens    uint64\npopularity_rank              int32\ndtype: object\nvalidation_preference_state.parquet    uid  item_id  state\n0  100   410868  liked\n1  100   732449  liked\n2  100   982903  liked\n3  100  1730273  liked\n4  100  2621343  liked state\nliked       418435\ndisliked     50689\nName: count, dtype: int64 uid        uint32\nitem_id    uint32\nstate      object\ndtype: object\ntest_preference_state.parquet    uid  item_id  state\n0  100   410868  liked\n1  100   732449  liked\n2  100   982903  liked\n3  100  1730273  liked\n4  100  2621343  liked state\nliked       432659\ndisliked     52117\nName: count, dtype: int64 uid        uint32\nitem_id    uint32\nstate      object\ndtype: object\ntorch 2.8.0+cpu threads 4 cpus 8\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 14,
      "role": "agent",
      "timestamp": "2026-08-31T18:27:03.958Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:27:03.958Z",
          "text": ""
        }
      ]
    },
    {
      "id": 15,
      "role": "agent",
      "timestamp": "2026-08-31T18:27:15.336Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:27:15.336Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:27:29.576Z",
          "callId": "call_92NqgMExIxAq1hmGHbSrR6ro",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Add File: /app/solution/build_popularity.py\\n+#!/usr/bin/env python3\\n+\\\"\\\"\\\"Build a structurally valid popularity ranking for either cutoff.\\\"\\\"\\\"\\n+from pathlib import Path\\n+import argparse\\n+import numpy as np\\n+import pandas as pd\\n+\\n+DATA = Path(\\\"/task/data\\\")\\n+\\n+\\n+def main() -> None:\\n+    parser = argparse.ArgumentParser()\\n+    parser.add_argument(\\\"--stage\\\", choices=[\\\"validation\\\", \\\"test\\\"], required=True)\\n+    parser.add_argument(\\\"--output\\\", type=Path, required=True)\\n+    args = parser.parse_args()\\n+    artifact = np.load(DATA / f\\\"{args.stage}_eligible_candidates.npz\\\")\\n+    uids = artifact[\\\"uids\\\"].astype(np.int64)\\n+    items = artifact[\\\"item_ids\\\"].astype(np.int64)\\n+    packed = artifact[\\\"packed_eligible\\\"]\\n+    rows = []\\n+    for row, uid in enumerate(uids):\\n+        eligible = np.unpackbits(\\n+            packed[row], count=len(items), bitorder=\\\"little\\\"\\n+        ).astype(bool)\\n+        chosen = items[eligible][:100]\\n+        rows.extend((int(uid), int(item), rank) for rank, item in enumerate(chosen, 1))\\n+    args.output.parent.mkdir(parents=True, exist_ok=True)\\n+    pd.DataFrame(rows, columns=[\\\"uid\\\", \\\"item_id\\\", \\\"rank\\\"]).to_parquet(\\n+        args.output, index=False\\n+    )\\n+\\n+\\n+if __name__ == \\\"__main__\\\":\\n+    main()\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:27:29.626Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 16,
      "role": "agent",
      "timestamp": "2026-08-31T18:27:31.395Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:27:31.395Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:27:34.913Z",
          "callId": "call_9NIp5d7kxZSSWRSFFiM0f4nE",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"ls -la /app/solution && /opt/task-venv/bin/python /app/solution/build_popularity.py --stage validation --output /app/solution/validation.parquet && /opt/task-venv/bin/python /task/evaluate_public.py /app/solution/validation.parquet\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":10000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:27:41.044Z",
            "content": "Script completed\nWall time 6.1 seconds\nOutput:\n\ntotal 16\ndrwxr-xr-x 1 agent agent 4096 Aug 31 18:27 .\ndrwxr-xr-x 1 agent agent 4096 Aug 31 18:22 ..\n-rw-r--r-- 1 agent agent 1148 Aug 31 18:27 build_popularity.py\n{\n  \"model\": \"/app/solution/validation.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.01071,\n    \"quality_users\": 4263\n  }\n}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 17,
      "role": "agent",
      "timestamp": "2026-08-31T18:27:46.717Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:27:46.717Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:27:49.879Z",
          "text": "The valid popularity fallback scores 0.010710 over 4,263 labeled users and is now saved. The main opportunity is personalization: I’m measuring how much target-user history intersects the 30k catalog, how recent histories behave, and whether validation relevance favors repeats, neighbors of prior tracks, or broad popularity. That will determine the most efficient history encoder and negative sampler."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:28:15.317Z",
          "callId": "call_6fxPH4QWxM9nSM35ADBtYrjk",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python - <<'PY'\\nfrom pathlib import Path\\nimport numpy as np, pandas as pd, pyarrow.parquet as pq, time\\nD=Path('/task/data')\\ntargets=pd.read_parquet(D/'target_users.parquet').uid.to_numpy(np.int64)\\ncat=pd.read_parquet(D/'candidate_catalog.parquet').item_id.to_numpy(np.int64)\\nT=set(targets.tolist()); C=set(cat.tolist())\\nfor fname in ['train_listens.parquet','val_listens.parquet']:\\n  pf=pq.ParquetFile(D/fname); n_t=n_tc=n_pos=n_posc=n_strongorg=0; us=set(); st=time.time()\\n  for b in pf.iter_batches(batch_size=1_000_000,columns=['uid','item_id','played_ratio_pct','is_organic']):\\n    x=b.to_pandas(); mt=x.uid.isin(T); y=x[mt]; n_t+=len(y); n_tc+=y.item_id.isin(C).sum();\\n    p=y.played_ratio_pct>=50; n_pos+=p.sum(); n_posc+=(p & y.item_id.isin(C)).sum(); n_strongorg+=((y.played_ratio_pct>=80)&(y.is_organic==1)&y.item_id.isin(C)).sum(); us.update(y.uid.unique())\\n  print(fname,'target',n_t,'target-cat',n_tc,'positive',n_pos,'positive-cat',n_posc,'strongorgcat',n_strongorg,'users',len(us),'sec',time.time()-st)\\nfor fname in ['train_likes.parquet','val_likes.parquet']:\\n x=pd.read_parquet(D/fname); y=x[x.uid.isin(T)]; print(fname,'target',len(y),'cat',y.item_id.isin(C).sum(),'organic-cat',((y.is_organic==1)&y.item_id.isin(C)).sum())\\n# validation truth ranks under popularity and whether train seen\\nvl=pd.read_parquet(D/'val_listens.parquet'); vk=pd.read_parquet(D/'val_likes.parquet')\\nrel1=vl[(vl.uid.isin(T))&(vl.is_organic==1)&(vl.played_ratio_pct>=80)&vl.item_id.isin(C)][['uid','item_id']].drop_duplicates(); rel1['g']=1\\nrel3=vk[(vk.uid.isin(T))&(vk.is_organic==1)&vk.item_id.isin(C)][['uid','item_id']].drop_duplicates(); rel3['g']=3\\ntruth=pd.concat([rel1,rel3]).sort_values('g').drop_duplicates(['uid','item_id'],keep='last')\\nrank={v:i+1 for i,v in enumerate(cat)}\\nprint('raw truth',len(truth),'users',truth.uid.nunique(),'grade counts',truth.g.value_counts().to_dict())\\nprint('pop ranks q',truth.item_id.map(rank).dropna().quantile([0,.1,.25,.5,.75,.9,1]).to_dict())\\nPY\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:28:26.338Z",
            "content": "Script running with cell ID 10\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 18,
      "role": "agent",
      "timestamp": "2026-08-31T18:28:28.106Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:28:28.106Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:28:28.873Z",
          "callId": "call_rYPylCPupCIAKjeJbm3zKEaE",
          "name": "wait",
          "input": {
            "cell_id": "10",
            "yield_time_ms": 30000,
            "max_tokens": 20000
          },
          "result": {
            "timestamp": "2026-08-31T18:28:32.391Z",
            "content": "Script completed\nWall time 3.5 seconds\nOutput:\n\ntrain_listens.parquet target 43222297 target-cat 31062540 positive 27367343 positive-cat 19959853 strongorgcat 8661020 users 8456 sec 14.3329176902771\nval_listens.parquet target 1482553 target-cat 999062 positive 955678 positive-cat 650295 strongorgcat 288828 users 7729 sec 0.5363175868988037\ntrain_likes.parquet target 690968 cat 472889 organic-cat 223046\nval_likes.parquet target 33177 cat 18307 organic-cat 10406\nraw truth 175729 users 6186 grade counts {1: 167201, 3: 8528}\npop ranks q {0.0: 1.0, 0.1: 212.0, 0.25: 1011.0, 0.5: 4132.0, 0.75: 11338.0, 0.9: 20151.0, 1.0: 30000.0}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 19,
      "role": "agent",
      "timestamp": "2026-08-31T18:28:40.834Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:28:40.834Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:28:52.996Z",
          "callId": "call_l8PCsPTd0wAmf0f1k6DvAg3p",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python - <<'PY'\\nimport pandas as pd,numpy as np,pyarrow.parquet as pq\\nfrom pathlib import Path\\nD=Path('/task/data'); z=np.load(D/'validation_eligible_candidates.npz'); uids=z['uids']; items=z['item_ids']; ip={int(x):i for i,x in enumerate(items)}; ur={int(x):i for i,x in enumerate(uids)}\\nsel=set(map(int,uids[:20])); seen={u:set() for u in sel}; cnt={u:0 for u in sel}\\nfor b in pq.ParquetFile(D/'train_listens.parquet').iter_batches(columns=['uid','item_id','played_ratio_pct'],batch_size=1_000_000):\\n x=b.to_pandas(); x=x[x.uid.isin(sel)&(x.played_ratio_pct>=50)&x.item_id.isin(ip)]\\n for u,g in x.groupby('uid'): seen[int(u)].update(map(int,g.item_id))\\nfor u in list(sel)[:20]:\\n bits=np.unpackbits(z['packed_eligible'][ur[u]],count=len(items),bitorder='little')\\n ss=seen[u]; elig_seen=sum(bits[ip[i]] for i in ss)\\n print(u,'seen',len(ss),'eligible seen',elig_seen,'excluded total',len(items)-bits.sum())\\nPY\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":10000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:29:03.201Z",
            "content": "Script completed\nWall time 10.2 seconds\nOutput:\n\n900 seen 26 eligible seen 0 excluded total 334\n2200 seen 1043 eligible seen 0 excluded total 1096\n800 seen 1910 eligible seen 0 excluded total 2524\n1700 seen 1429 eligible seen 0 excluded total 2164\n300 seen 45 eligible seen 0 excluded total 69\n2100 seen 562 eligible seen 0 excluded total 645\n700 seen 1233 eligible seen 0 excluded total 1653\n1600 seen 1207 eligible seen 0 excluded total 1524\n2500 seen 555 eligible seen 0 excluded total 636\n200 seen 163 eligible seen 0 excluded total 168\n1100 seen 1337 eligible seen 0 excluded total 1440\n2000 seen 265 eligible seen 0 excluded total 374\n600 seen 657 eligible seen 0 excluded total 680\n1500 seen 503 eligible seen 0 excluded total 524\n2400 seen 437 eligible seen 0 excluded total 471\n100 seen 600 eligible seen 0 excluded total 682\n1000 seen 429 eligible seen 0 excluded total 499\n1900 seen 1786 eligible seen 0 excluded total 2041\n1400 seen 1139 eligible seen 0 excluded total 1264\n2300 seen 1064 eligible seen 0 excluded total 1406\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 20,
      "role": "agent",
      "timestamp": "2026-08-31T18:29:24.045Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:29:24.045Z",
          "text": ""
        }
      ]
    },
    {
      "id": 21,
      "role": "agent",
      "timestamp": "2026-08-31T18:29:42.707Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:29:42.707Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:29:47.175Z",
          "callId": "call_BxSmcKRkNsAJ86hjzUalTA4K",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python - <<'PY'\\nimport pyarrow.parquet as pq\\np=pq.ParquetFile('/task/data/train_listens.parquet')\\nfor i in range(p.metadata.num_row_groups):\\n c=p.metadata.row_group(i).column(p.schema.names.index('timestamp')).statistics\\n print(i,c.min,c.max,p.metadata.row_group(i).num_rows)\\nPY\",\"workdir\":\"/app\",\"yield_time_ms\":10000,\"max_output_tokens\":10000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:29:47.669Z",
            "content": "Script completed\nWall time 0.5 seconds\nOutput:\n\n0 15 24786690 1048576\n1 185 24786725 1048576\n2 15320 24786790 1048576\n3 3625 24786795 1048576\n4 5735 24786740 1048576\n5 120 24786775 1048576\n6 140 24786750 1048576\n7 220 24786745 1048576\n8 1890 24786770 1048576\n9 65 24786735 1048576\n10 15 24786720 1048576\n11 350 24786795 1048576\n12 60 24786730 1048576\n13 1370 24786790 1048576\n14 5 24786770 1048576\n15 30 24786785 1048576\n16 9145 24786750 1048576\n17 95 24786795 1048576\n18 20 24786760 1048576\n19 0 24786760 1048576\n20 40 24786795 1048576\n21 300 24786790 1048576\n22 45 24786730 1048576\n23 530 24786730 1048576\n24 8680 24786790 1048576\n25 65 24786785 1048576\n26 20 24786785 1048576\n27 40 24786725 1048576\n28 125 24786770 1048576\n29 7330 24786785 1048576\n30 30 24786775 1048576\n31 60 24786670 1048576\n32 20 24786795 1048576\n33 355 24786795 1048576\n34 565 24786735 1048576\n35 205 24786785 1048576\n36 50 24786740 1048576\n37 1190 24786775 1048576\n38 190 24786705 1048576\n39 10 24786760 1048576\n40 230 24786710 1048576\n41 20 24786690 492543\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 22,
      "role": "agent",
      "timestamp": "2026-08-31T18:29:50.804Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:29:50.804Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:29:54.527Z",
          "callId": "call_ryzdUMXvp8yI7Q6bvnKrH9mQ",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python - <<'PY'\\nimport pyarrow.parquet as pq\\nx=pq.read_table('/task/data/train_listens.parquet',columns=['uid','timestamp','item_id']).slice(0,30).to_pandas(); print(x.to_string(index=False))\\nPY\",\"workdir\":\"/app\",\"yield_time_ms\":10000,\"max_output_tokens\":5000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:29:56.482Z",
            "content": "Script completed\nWall time 1.9 seconds\nOutput:\n\n uid  timestamp  item_id\n 100      39420  8326270\n 100      39420  1441281\n 100      39625   286361\n 100      40110   732449\n 100      40360  3397170\n 100      40380  7849270\n 100      40640  1449307\n 100      40785  6887232\n 100      40885  2996197\n 100      41130  6474571\n 100      41545  7847600\n 100      41580  7509517\n 100      41580   470320\n 100      42115  6641244\n 100      42115  2581903\n 100      42115  5485459\n 100      42115  5474898\n 100      42115  3088475\n 100      42115  7521298\n 100      42210  8329413\n 100      42380  1853659\n 100      42520  1302519\n 100      43425  7498961\n 100      43425  3630949\n 100      43425  2729049\n 100      43425   732246\n 100      43425  5910506\n 100      43720  1907213\n 100      43720  6451550\n 100      43910  2170705\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 23,
      "role": "agent",
      "timestamp": "2026-08-31T18:30:00.427Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:30:00.427Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:30:02.109Z",
          "callId": "call_saTNuVwpKfRDAlQI0y3JlB5Z",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"free -h && df -h /app\",\"workdir\":\"/app\",\"yield_time_ms\":10000,\"max_output_tokens\":2000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:30:02.161Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n/bin/sh: 1: free: not found\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 24,
      "role": "agent",
      "timestamp": "2026-08-31T18:30:03.923Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:30:03.923Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:30:06.021Z",
          "callId": "call_mnOKSsOcNMjiS7DZetOKOETv",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"sed -n '1,12p' /proc/meminfo\\ndf -h /app\",\"workdir\":\"/app\",\"yield_time_ms\":10000,\"max_output_tokens\":2000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:30:06.072Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\nMemTotal:       15988980 kB\nMemFree:         1914336 kB\nMemAvailable:   14934508 kB\nBuffers:          227092 kB\nCached:         12500220 kB\nSwapCached:            0 kB\nActive:           501636 kB\nInactive:       12498080 kB\nActive(anon):     298856 kB\nInactive(anon):        0 kB\nActive(file):     202780 kB\nInactive(file): 12498080 kB\nFilesystem      Size  Used Avail Use% Mounted on\noverlay          96G   14G   83G  15% /\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 25,
      "role": "agent",
      "timestamp": "2026-08-31T18:30:25.706Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:30:25.706Z",
          "text": ""
        }
      ]
    },
    {
      "id": 26,
      "role": "agent",
      "timestamp": "2026-08-31T18:30:44.357Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:30:44.357Z",
          "text": ""
        }
      ]
    },
    {
      "id": 27,
      "role": "agent",
      "timestamp": "2026-08-31T18:31:02.996Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:31:02.996Z",
          "text": ""
        }
      ]
    },
    {
      "id": 28,
      "role": "agent",
      "timestamp": "2026-08-31T18:31:21.622Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:31:21.622Z",
          "text": ""
        }
      ]
    },
    {
      "id": 29,
      "role": "agent",
      "timestamp": "2026-08-31T18:31:40.312Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:31:40.312Z",
          "text": ""
        }
      ]
    },
    {
      "id": 30,
      "role": "agent",
      "timestamp": "2026-08-31T18:31:58.933Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:31:58.933Z",
          "text": ""
        }
      ]
    },
    {
      "id": 31,
      "role": "agent",
      "timestamp": "2026-08-31T18:32:04.792Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:32:04.792Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:36:16.502Z",
          "callId": "call_yWivaC2I6ZRn13TRA2J4yILC",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Add File: /app/solution/model.py\\n+\\\"\\\"\\\"Strictly decomposable PyTorch two-tower retrieval model.\\\"\\\"\\\"\\n+from __future__ import annotations\\n+\\n+import torch\\n+from torch import nn\\n+import torch.nn.functional as F\\n+\\n+\\n+class UserTower(nn.Module):\\n+    \\\"\\\"\\\"Encode positive/negative interaction history without a user-ID table.\\\"\\\"\\\"\\n+\\n+    def __init__(self, num_items: int, hidden_dim: int = 96, output_dim: int = 64):\\n+        super().__init__()\\n+        # Index zero is padding. This table represents tracks in histories, not users.\\n+        self.history_embedding = nn.Embedding(num_items + 1, hidden_dim, padding_idx=0)\\n+        self.network = nn.Sequential(\\n+            nn.Linear(hidden_dim * 3 + 4, 192),\\n+            nn.LayerNorm(192),\\n+            nn.SiLU(),\\n+            nn.Linear(192, 128),\\n+            nn.SiLU(),\\n+            nn.Linear(128, output_dim),\\n+        )\\n+\\n+    @staticmethod\\n+    def _pool(emb: torch.Tensor, weights: torch.Tensor) -> torch.Tensor:\\n+        denom = weights.sum(dim=1, keepdim=True).clamp_min(1e-6)\\n+        return (emb * weights.unsqueeze(-1)).sum(dim=1) / denom\\n+\\n+    def forward(\\n+        self,\\n+        history_ids: torch.Tensor,\\n+        long_weights: torch.Tensor,\\n+        short_weights: torch.Tensor,\\n+        negative_ids: torch.Tensor,\\n+        negative_weights: torch.Tensor,\\n+        numeric: torch.Tensor,\\n+    ) -> torch.Tensor:\\n+        positive = self.history_embedding(history_ids)\\n+        long_pool = self._pool(positive, long_weights)\\n+        short_pool = self._pool(positive, short_weights)\\n+        negative = self._pool(self.history_embedding(negative_ids), negative_weights)\\n+        vector = self.network(torch.cat([long_pool, short_pool, negative, numeric], dim=1))\\n+        return F.normalize(vector, dim=1)\\n+\\n+\\n+class ItemTower(nn.Module):\\n+    \\\"\\\"\\\"Independently encode a catalog item for offline ANN indexing.\\\"\\\"\\\"\\n+\\n+    def __init__(self, num_items: int, feature_dim: int = 4, hidden_dim: int = 96, output_dim: int = 64):\\n+        super().__init__()\\n+        self.item_embedding = nn.Embedding(num_items + 1, hidden_dim, padding_idx=0)\\n+        self.network = nn.Sequential(\\n+            nn.Linear(hidden_dim + feature_dim, 160),\\n+            nn.LayerNorm(160),\\n+            nn.SiLU(),\\n+            nn.Linear(160, 128),\\n+            nn.SiLU(),\\n+            nn.Linear(128, output_dim),\\n+        )\\n+\\n+    def forward(self, item_ids: torch.Tensor, features: torch.Tensor) -> torch.Tensor:\\n+        vector = self.network(torch.cat([self.item_embedding(item_ids), features], dim=-1))\\n+        return F.normalize(vector, dim=-1)\\n+\\n+\\n+class TwoTower(nn.Module):\\n+    def __init__(self, num_items: int, output_dim: int = 64):\\n+        super().__init__()\\n+        self.user_tower = UserTower(num_items, output_dim=output_dim)\\n+        self.item_tower = ItemTower(num_items, output_dim=output_dim)\\n+\\n*** Add File: /app/solution/train_ranker.py\\n+#!/usr/bin/env python3\\n+\\\"\\\"\\\"Preprocess events, train the two towers, and emit an eligible ranking.\\n+\\n+The data path is event-stream based: it never constructs a user-item matrix.\\n+Catalog item IDs are mapped to dense embedding indices only.\\n+\\\"\\\"\\\"\\n+from __future__ import annotations\\n+\\n+import argparse\\n+import json\\n+import math\\n+import random\\n+from collections import defaultdict\\n+from pathlib import Path\\n+from typing import Iterator\\n+\\n+import numpy as np\\n+import pandas as pd\\n+import pyarrow.parquet as pq\\n+import torch\\n+import torch.nn.functional as F\\n+\\n+from model import TwoTower\\n+\\n+DATA = Path(\\\"/task/data\\\")\\n+SHELF_GAP = 1_800\\n+WINDOW = 7 * 24 * 60 * 60\\n+DAY = 24 * 60 * 60\\n+MAX_HISTORY = 256\\n+MAX_NEGATIVE = 64\\n+\\n+\\n+def seed_everything(seed: int) -> None:\\n+    random.seed(seed)\\n+    np.random.seed(seed)\\n+    torch.manual_seed(seed)\\n+\\n+\\n+def iter_user_groups(path: Path) -> Iterator[tuple[int, dict[str, np.ndarray]]]:\\n+    \\\"\\\"\\\"Stream a uid/time-sorted listen parquet, retaining at most one user carry.\\\"\\\"\\\"\\n+    columns = [\\\"uid\\\", \\\"timestamp\\\", \\\"item_id\\\", \\\"is_organic\\\", \\\"played_ratio_pct\\\"]\\n+    carry: dict[str, np.ndarray] | None = None\\n+    for batch in pq.ParquetFile(path).iter_batches(batch_size=750_000, columns=columns):\\n+        current = {name: batch.column(i).to_numpy(zero_copy_only=False) for i, name in enumerate(columns)}\\n+        if carry is not None:\\n+            current = {name: np.concatenate([carry[name], current[name]]) for name in columns}\\n+        uids = current[\\\"uid\\\"]\\n+        boundaries = np.flatnonzero(uids[1:] != uids[:-1]) + 1\\n+        starts = np.r_[0, boundaries]\\n+        ends = np.r_[boundaries, len(uids)]\\n+        for start, end in zip(starts[:-1], ends[:-1]):\\n+            yield int(uids[start]), {name: values[start:end] for name, values in current.items()}\\n+        start = int(starts[-1])\\n+        carry = {name: values[start:] for name, values in current.items()}\\n+    if carry is not None and len(carry[\\\"uid\\\"]):\\n+        yield int(carry[\\\"uid\\\"][0]), carry\\n+\\n+\\n+def event_groups(paths: list[Path], columns: list[str]) -> dict[int, pd.DataFrame]:\\n+    frames = [pd.read_parquet(path, columns=columns) for path in paths]\\n+    frame = pd.concat(frames, ignore_index=True) if len(frames) > 1 else frames[0]\\n+    frame = frame.sort_values([\\\"uid\\\", \\\"timestamp\\\"])\\n+    return {int(uid): group.drop(columns=\\\"uid\\\") for uid, group in frame.groupby(\\\"uid\\\", sort=False)}\\n+\\n+\\n+def map_catalog(raw_items: np.ndarray, sorted_ids: np.ndarray, sorted_to_pos: np.ndarray) -> np.ndarray:\\n+    at = np.searchsorted(sorted_ids, raw_items)\\n+    good = at < len(sorted_ids)\\n+    result = np.full(len(raw_items), -1, dtype=np.int32)\\n+    matched = good & (sorted_ids[np.minimum(at, len(sorted_ids) - 1)] == raw_items)\\n+    result[matched] = sorted_to_pos[at[matched]]\\n+    return result\\n+\\n+\\n+def active_items(events: pd.DataFrame | None, cutoff: int, item_map) -> np.ndarray:\\n+    if events is None or events.empty:\\n+        return np.empty(0, dtype=np.int32)\\n+    rows = events[events.timestamp < cutoff]\\n+    if rows.empty:\\n+        return np.empty(0, dtype=np.int32)\\n+    # Last action independently controls each explicit channel.\\n+    last = rows.sort_values(\\\"timestamp\\\").drop_duplicates(\\\"item_id\\\", keep=\\\"last\\\")\\n+    last = last[last.active == 1]\\n+    return np.asarray([item_map.get(int(x), -1) for x in last.item_id if int(x) in item_map], dtype=np.int32)\\n+\\n+\\n+def state_channel(on_paths: list[Path], off_paths: list[Path]) -> dict[int, pd.DataFrame]:\\n+    frames = []\\n+    for path in on_paths:\\n+        x = pd.read_parquet(path, columns=[\\\"uid\\\", \\\"timestamp\\\", \\\"item_id\\\"])\\n+        x[\\\"active\\\"] = np.int8(1)\\n+        frames.append(x)\\n+    for path in off_paths:\\n+        x = pd.read_parquet(path, columns=[\\\"uid\\\", \\\"timestamp\\\", \\\"item_id\\\"])\\n+        x[\\\"active\\\"] = np.int8(0)\\n+        frames.append(x)\\n+    frame = pd.concat(frames, ignore_index=True).sort_values([\\\"uid\\\", \\\"timestamp\\\"])\\n+    return {int(uid): group.drop(columns=\\\"uid\\\") for uid, group in frame.groupby(\\\"uid\\\", sort=False)}\\n+\\n+\\n+def select_history(\\n+    positions: np.ndarray,\\n+    timestamps: np.ndarray,\\n+    ratios: np.ndarray,\\n+    organic: np.ndarray,\\n+    cutoff: int,\\n+    liked: np.ndarray,\\n+) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:\\n+    mask = (positions >= 0) & (timestamps < cutoff) & (ratios >= 50)\\n+    p, t, r, o = positions[mask], timestamps[mask], ratios[mask], organic[mask]\\n+    if len(p):\\n+        # Aggregate event strength and retain last-event recency per unique track.\\n+        order = np.argsort(p, kind=\\\"stable\\\")\\n+        p, t, r, o = p[order], t[order], r[order], o[order]\\n+        unique, starts = np.unique(p, return_index=True)\\n+        strength = np.add.reduceat(np.clip(r / 100.0, 0.5, 1.25) * (1.0 + 0.45 * o), starts)\\n+        last_time = np.maximum.reduceat(t, starts)\\n+        base = np.log1p(strength)\\n+        long_w = base * np.exp(-(cutoff - last_time) / (120 * DAY))\\n+        short_w = base * np.exp(-(cutoff - last_time) / (18 * DAY))\\n+    else:\\n+        unique = np.empty(0, dtype=np.int32)\\n+        long_w = short_w = np.empty(0, dtype=np.float32)\\n+    if len(liked):\\n+        all_ids = np.unique(np.concatenate([unique, liked]))\\n+        lw = np.zeros(len(all_ids), np.float32)\\n+        sw = np.zeros(len(all_ids), np.float32)\\n+        if len(unique):\\n+            ix = np.searchsorted(all_ids, unique)\\n+            lw[ix], sw[ix] = long_w, short_w\\n+        ix = np.searchsorted(all_ids, liked)\\n+        lw[ix] += 2.5\\n+        sw[ix] += 1.5\\n+        unique, long_w, short_w = all_ids, lw, sw\\n+    if len(unique) > MAX_HISTORY:\\n+        keep = np.argpartition(long_w + short_w, -MAX_HISTORY)[-MAX_HISTORY:]\\n+        unique, long_w, short_w = unique[keep], long_w[keep], short_w[keep]\\n+    return unique.astype(np.int32), long_w.astype(np.float32), short_w.astype(np.float32), mask\\n+\\n+\\n+def pad(values: np.ndarray, size: int, dtype, offset: int = 0) -> np.ndarray:\\n+    result = np.zeros(size, dtype=dtype)\\n+    n = min(size, len(values))\\n+    if n:\\n+        result[:n] = values[:n] + offset\\n+    return result\\n+\\n+\\n+def build_cache(stage: str, output: Path, weeks: int) -> None:\\n+    test = stage == \\\"test\\\"\\n+    listen_paths = [DATA / \\\"train_listens.parquet\\\"]\\n+    suffixes = [\\\"train\\\"]\\n+    if test:\\n+        listen_paths.append(DATA / \\\"val_listens.parquet\\\")\\n+        suffixes.append(\\\"val\\\")\\n+    end = 25_393_400 if test else 24_786_800\\n+    cutoffs = [end - j * (WINDOW + SHELF_GAP) for j in range(weeks, 0, -1)]\\n+\\n+    catalog = pd.read_parquet(DATA / \\\"candidate_catalog.parquet\\\")\\n+    raw_catalog = catalog.item_id.to_numpy(np.int64)\\n+    item_map = {int(item): i for i, item in enumerate(raw_catalog)}\\n+    order = np.argsort(raw_catalog)\\n+    sorted_ids, sorted_to_pos = raw_catalog[order], order.astype(np.int32)\\n+\\n+    like_on = [DATA / f\\\"{s}_likes.parquet\\\" for s in suffixes]\\n+    like_off = [DATA / f\\\"{s}_unlikes.parquet\\\" for s in suffixes]\\n+    dislike_on = [DATA / f\\\"{s}_dislikes.parquet\\\" for s in suffixes]\\n+    dislike_off = [DATA / f\\\"{s}_undislikes.parquet\\\" for s in suffixes]\\n+    likes = state_channel(like_on, like_off)\\n+    dislikes = state_channel(dislike_on, dislike_off)\\n+    organic_likes = event_groups(like_on, [\\\"uid\\\", \\\"timestamp\\\", \\\"item_id\\\", \\\"is_organic\\\"])\\n+\\n+    # Validation has one stream. Test appends the small validation stream by uid.\\n+    val_listens = {}\\n+    if test:\\n+        vf = pd.read_parquet(listen_paths[1], columns=[\\\"uid\\\", \\\"timestamp\\\", \\\"item_id\\\", \\\"is_organic\\\", \\\"played_ratio_pct\\\"])\\n+        val_listens = {int(uid): g for uid, g in vf.groupby(\\\"uid\\\", sort=False)}\\n+\\n+    histories, longs, shorts, negatives, neg_weights, numerics = [], [], [], [], [], []\\n+    target_lists, target_gains = [], []\\n+    inference = None\\n+    targets = set(pd.read_parquet(DATA / \\\"target_users.parquet\\\").uid.astype(int))\\n+    for number, (uid, data) in enumerate(iter_user_groups(listen_paths[0])):\\n+        if uid not in targets:\\n+            continue\\n+        if test and uid in val_listens:\\n+            extra = val_listens[uid]\\n+            for name in [\\\"timestamp\\\", \\\"item_id\\\", \\\"is_organic\\\", \\\"played_ratio_pct\\\"]:\\n+                data[name] = np.concatenate([data[name], extra[name].to_numpy()])\\n+            chronology = np.argsort(data[\\\"timestamp\\\"], kind=\\\"stable\\\")\\n+            data = {name: value[chronology] for name, value in data.items()}\\n+        pos = map_catalog(data[\\\"item_id\\\"].astype(np.int64), sorted_ids, sorted_to_pos)\\n+        user_likes = likes.get(uid)\\n+        user_dislikes = dislikes.get(uid)\\n+        user_organic_likes = organic_likes.get(uid)\\n+\\n+        for cutoff in cutoffs + [end]:\\n+            liked = active_items(user_likes, cutoff, item_map)\\n+            disliked = active_items(user_dislikes, cutoff, item_map)\\n+            hist, lw, sw, _ = select_history(\\n+                pos, data[\\\"timestamp\\\"], data[\\\"played_ratio_pct\\\"], data[\\\"is_organic\\\"], cutoff, liked\\n+            )\\n+            if not len(hist):\\n+                continue\\n+            histories.append(pad(hist, MAX_HISTORY, np.int32, 1))\\n+            longs.append(pad(lw, MAX_HISTORY, np.float32))\\n+            shorts.append(pad(sw, MAX_HISTORY, np.float32))\\n+            negatives.append(pad(disliked[:MAX_NEGATIVE], MAX_NEGATIVE, np.int32, 1))\\n+            neg_weights.append(pad(np.ones(min(len(disliked), MAX_NEGATIVE)), MAX_NEGATIVE, np.float32))\\n+            numerics.append(np.asarray([\\n+                math.log1p(len(hist)) / 6.0,\\n+                math.log1p(np.count_nonzero(data[\\\"timestamp\\\"] < cutoff)) / 10.0,\\n+                math.log1p(len(liked)) / 5.0,\\n+                math.log1p(len(disliked)) / 4.0,\\n+            ], np.float32))\\n+            if cutoff == end:\\n+                target_lists.append(np.empty(0, np.int32))\\n+                target_gains.append(np.empty(0, np.float32))\\n+                continue\\n+\\n+            prior_seen = set(pos[(pos >= 0) & (data[\\\"timestamp\\\"] < cutoff)].tolist())\\n+            future = (\\n+                (data[\\\"timestamp\\\"] >= cutoff + SHELF_GAP)\\n+                & (data[\\\"timestamp\\\"] < cutoff + SHELF_GAP + WINDOW)\\n+                & (data[\\\"is_organic\\\"] == 1)\\n+                & (data[\\\"played_ratio_pct\\\"] >= 80)\\n+                & (pos >= 0)\\n+            )\\n+            grades: dict[int, int] = {int(x): 1 for x in np.unique(pos[future]) if int(x) not in prior_seen}\\n+            if user_organic_likes is not None:\\n+                q = user_organic_likes\\n+                q = q[(q.timestamp >= cutoff + SHELF_GAP) & (q.timestamp < cutoff + SHELF_GAP + WINDOW) & (q.is_organic == 1)]\\n+                for item in q.item_id:\\n+                    mapped = item_map.get(int(item))\\n+                    if mapped is not None and mapped not in prior_seen:\\n+                        grades[mapped] = 3\\n+            item_targets = np.fromiter(grades.keys(), dtype=np.int32)\\n+            gains = np.fromiter((7.0 if g == 3 else 1.0 for g in grades.values()), dtype=np.float32)\\n+            target_lists.append(item_targets)\\n+            target_gains.append(gains)\\n+\\n+        if number and number % 1500 == 0:\\n+            print(f\\\"preprocessed {number:,} users\\\", flush=True)\\n+\\n+    # The last context for every processed user is inference; train contexts are nonempty target rows.\\n+    lengths = np.asarray([len(x) for x in target_lists], np.int32)\\n+    is_train = lengths > 0\\n+    is_infer = lengths == 0\\n+    offsets = np.r_[0, np.cumsum(lengths[is_train], dtype=np.int64)]\\n+    flat_targets = np.concatenate([x for x, ok in zip(target_lists, is_train) if ok]).astype(np.int32)\\n+    flat_gains = np.concatenate([x for x, ok in zip(target_gains, is_train) if ok]).astype(np.float32)\\n+    # recover context uids: construction produces weeks+1 contexts/user unless empty history\\n+    # Re-run order cheaply from target uids; all target users have sufficient history here.\\n+    user_order = pd.read_parquet(DATA / \\\"target_users.parquet\\\").uid.to_numpy(np.int64)\\n+    infer_count = int(is_infer.sum())\\n+    if infer_count != len(user_order):\\n+        raise RuntimeError(f\\\"expected {len(user_order)} inference contexts, got {infer_count}\\\")\\n+    np.savez_compressed(\\n+        output,\\n+        history=np.stack(histories), long=np.stack(longs), short=np.stack(shorts),\\n+        negative=np.stack(negatives), negative_weight=np.stack(neg_weights), numeric=np.stack(numerics),\\n+        train_rows=np.flatnonzero(is_train).astype(np.int32), infer_rows=np.flatnonzero(is_infer).astype(np.int32),\\n+        target_offsets=offsets, targets=flat_targets, target_gains=flat_gains, infer_uids=user_order,\\n+    )\\n+    print(json.dumps({\\\"cache\\\": str(output), \\\"contexts\\\": len(histories), \\\"train_contexts\\\": int(is_train.sum()), \\\"targets\\\": len(flat_targets)}))\\n+\\n+\\n+def item_features() -> np.ndarray:\\n+    catalog = pd.read_parquet(DATA / \\\"candidate_catalog.parquet\\\")\\n+    positive = np.log1p(catalog.positive_listens.to_numpy(np.float32))\\n+    organic = np.log1p(catalog.organic_positive_listens.to_numpy(np.float32))\\n+    share = catalog.organic_positive_listens.to_numpy(np.float32) / np.maximum(catalog.positive_listens.to_numpy(np.float32), 1)\\n+    rank = np.log1p(catalog.popularity_rank.to_numpy(np.float32))\\n+    raw = np.c_[positive, organic, share, rank].astype(np.float32)\\n+    return (raw - raw.mean(0)) / (raw.std(0) + 1e-6)\\n+\\n+\\n+def tensor_rows(cache, name: str, rows: np.ndarray, device=\\\"cpu\\\") -> torch.Tensor:\\n+    return torch.from_numpy(cache[name][rows]).to(device)\\n+\\n+\\n+def train_model(cache_path: Path, model_path: Path, epochs: int, seed: int, dim: int) -> None:\\n+    seed_everything(seed)\\n+    torch.set_num_threads(min(8, torch.get_num_threads()))\\n+    cache = np.load(cache_path)\\n+    rows = cache[\\\"train_rows\\\"]\\n+    offsets, targets, gains = cache[\\\"target_offsets\\\"], cache[\\\"targets\\\"], cache[\\\"target_gains\\\"]\\n+    features = torch.from_numpy(item_features())\\n+    num_items = len(features)\\n+    model = TwoTower(num_items, output_dim=dim)\\n+    optimizer = torch.optim.AdamW(model.parameters(), lr=2.5e-3, weight_decay=2e-5)\\n+    generator = np.random.default_rng(seed)\\n+    batch_size, negatives_per = 192, 40\\n+    pop_prob = np.power(np.arange(1, num_items + 1, dtype=np.float64), -0.35)\\n+    pop_prob /= pop_prob.sum()\\n+\\n+    model.train()\\n+    for epoch in range(epochs):\\n+        sequence = generator.permutation(len(rows))\\n+        total = batches = 0.0\\n+        for start in range(0, len(sequence), batch_size):\\n+            cx = sequence[start:start + batch_size]\\n+            data_rows = rows[cx]\\n+            chosen = []\\n+            for index in cx:\\n+                lo, hi = offsets[index], offsets[index + 1]\\n+                probability = gains[lo:hi].astype(np.float64)\\n+                probability /= probability.sum()\\n+                chosen.append(targets[lo + generator.choice(hi - lo, p=probability)])\\n+            positive = np.asarray(chosen, np.int64)\\n+            # Half popularity-shaped and half uniform negatives improves both head and tail separation.\\n+            n = len(cx)\\n+            hard = generator.choice(num_items, size=(n, negatives_per // 2), p=pop_prob)\\n+            uniform = generator.integers(0, num_items, size=(n, negatives_per - negatives_per // 2))\\n+            negative = np.concatenate([hard, uniform], axis=1).astype(np.int64)\\n+            collision = negative == positive[:, None]\\n+            negative[collision] = (negative[collision] + 1) % num_items\\n+\\n+            user = model.user_tower(\\n+                tensor_rows(cache, \\\"history\\\", data_rows), tensor_rows(cache, \\\"long\\\", data_rows),\\n+                tensor_rows(cache, \\\"short\\\", data_rows), tensor_rows(cache, \\\"negative\\\", data_rows),\\n+                tensor_rows(cache, \\\"negative_weight\\\", data_rows), tensor_rows(cache, \\\"numeric\\\", data_rows),\\n+            )\\n+            pos_ids = torch.from_numpy(positive + 1)\\n+            pos_vec = model.item_tower(pos_ids, features[positive])\\n+            neg_ids = torch.from_numpy(negative + 1)\\n+            neg_vec = model.item_tower(neg_ids, features[negative])\\n+            pos_score = (user * pos_vec).sum(1, keepdim=True)\\n+            neg_score = (user[:, None, :] * neg_vec).sum(2)\\n+            loss = F.softplus((neg_score - pos_score) * 9.0).mean()\\n+            optimizer.zero_grad(set_to_none=True)\\n+            loss.backward()\\n+            torch.nn.utils.clip_grad_norm_(model.parameters(), 5.0)\\n+            optimizer.step()\\n+            total += float(loss); batches += 1\\n+        print(f\\\"epoch {epoch + 1:02d} loss={total / batches:.5f}\\\", flush=True)\\n+    torch.save({\\\"state_dict\\\": model.state_dict(), \\\"num_items\\\": num_items, \\\"dim\\\": dim, \\\"seed\\\": seed}, model_path)\\n+\\n+\\n+@torch.inference_mode()\\n+def rank(cache_path: Path, model_path: Path, stage: str, output: Path, pop_blend: float) -> None:\\n+    cache = np.load(cache_path)\\n+    checkpoint = torch.load(model_path, map_location=\\\"cpu\\\", weights_only=True)\\n+    model = TwoTower(checkpoint[\\\"num_items\\\"], output_dim=checkpoint[\\\"dim\\\"])\\n+    model.load_state_dict(checkpoint[\\\"state_dict\\\"])\\n+    model.eval()\\n+    features = torch.from_numpy(item_features())\\n+    all_ids = torch.arange(1, checkpoint[\\\"num_items\\\"] + 1)\\n+    item_vectors = []\\n+    for start in range(0, len(all_ids), 2048):\\n+        ids = all_ids[start:start + 2048]\\n+        item_vectors.append(model.item_tower(ids, features[start:start + len(ids)]))\\n+    item_vectors = torch.cat(item_vectors)\\n+    rows = cache[\\\"infer_rows\\\"]\\n+    user_vectors = []\\n+    for start in range(0, len(rows), 256):\\n+        ix = rows[start:start + 256]\\n+        user_vectors.append(model.user_tower(\\n+            tensor_rows(cache, \\\"history\\\", ix), tensor_rows(cache, \\\"long\\\", ix), tensor_rows(cache, \\\"short\\\", ix),\\n+            tensor_rows(cache, \\\"negative\\\", ix), tensor_rows(cache, \\\"negative_weight\\\", ix), tensor_rows(cache, \\\"numeric\\\", ix),\\n+        ))\\n+    user_vectors = torch.cat(user_vectors)\\n+    eligibility = np.load(DATA / f\\\"{stage}_eligible_candidates.npz\\\")\\n+    uids = eligibility[\\\"uids\\\"].astype(np.int64)\\n+    candidate_items = eligibility[\\\"item_ids\\\"].astype(np.int64)\\n+    if not np.array_equal(uids, cache[\\\"infer_uids\\\"]):\\n+        raise RuntimeError(\\\"cache user order does not align with eligibility\\\")\\n+    pop = -np.log1p(np.arange(len(candidate_items), dtype=np.float32))\\n+    pop = (pop - pop.mean()) / pop.std()\\n+    result = []\\n+    for start in range(0, len(uids), 128):\\n+        stop = min(start + 128, len(uids))\\n+        score = (user_vectors[start:stop] @ item_vectors.T).numpy()\\n+        score += pop_blend * pop[None, :]\\n+        mask = np.unpackbits(eligibility[\\\"packed_eligible\\\"][start:stop], axis=1, count=len(candidate_items), bitorder=\\\"little\\\").astype(bool)\\n+        score[~mask] = -np.inf\\n+        top = np.argpartition(score, -100, axis=1)[:, -100:]\\n+        top_scores = np.take_along_axis(score, top, axis=1)\\n+        top = np.take_along_axis(top, np.argsort(-top_scores, axis=1), axis=1)\\n+        for row, uid in enumerate(uids[start:stop]):\\n+            result.extend((int(uid), int(candidate_items[col]), rank_) for rank_, col in enumerate(top[row], 1))\\n+    pd.DataFrame(result, columns=[\\\"uid\\\", \\\"item_id\\\", \\\"rank\\\"]).to_parquet(output, index=False)\\n+\\n+\\n+def parse_args() -> argparse.Namespace:\\n+    p = argparse.ArgumentParser()\\n+    sub = p.add_subparsers(dest=\\\"command\\\", required=True)\\n+    q = sub.add_parser(\\\"preprocess\\\")\\n+    q.add_argument(\\\"--stage\\\", choices=[\\\"validation\\\", \\\"test\\\"], required=True)\\n+    q.add_argument(\\\"--output\\\", type=Path, required=True)\\n+    q.add_argument(\\\"--weeks\\\", type=int, default=6)\\n+    q = sub.add_parser(\\\"train\\\")\\n+    q.add_argument(\\\"--cache\\\", type=Path, required=True)\\n+    q.add_argument(\\\"--model\\\", type=Path, required=True)\\n+    q.add_argument(\\\"--epochs\\\", type=int, default=16)\\n+    q.add_argument(\\\"--seed\\\", type=int, default=2026)\\n+    q.add_argument(\\\"--dim\\\", type=int, default=64)\\n+    q = sub.add_parser(\\\"rank\\\")\\n+    q.add_argument(\\\"--cache\\\", type=Path, required=True)\\n+    q.add_argument(\\\"--model\\\", type=Path, required=True)\\n+    q.add_argument(\\\"--stage\\\", choices=[\\\"validation\\\", \\\"test\\\"], required=True)\\n+    q.add_argument(\\\"--output\\\", type=Path, required=True)\\n+    q.add_argument(\\\"--pop-blend\\\", type=float, default=0.0)\\n+    return p.parse_args()\\n+\\n+\\n+if __name__ == \\\"__main__\\\":\\n+    args = parse_args()\\n+    if args.command == \\\"preprocess\\\":\\n+        build_cache(args.stage, args.output, args.weeks)\\n+    elif args.command == \\\"train\\\":\\n+        train_model(args.cache, args.model, args.epochs, args.seed, args.dim)\\n+    else:\\n+        rank(args.cache, args.model, args.stage, args.output, args.pop_blend)\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:36:16.543Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 32,
      "role": "agent",
      "timestamp": "2026-08-31T18:36:26.825Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:36:26.825Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:36:40.143Z",
          "callId": "call_rcY9oqVn45eU0zb98GavvgxI",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Update File: /app/solution/train_ranker.py\\n@@\\n-    target_lists, target_gains = [], []\\n+    target_lists, target_gains, infer_flags, infer_uids = [], [], [], []\\n@@\\n             histories.append(pad(hist, MAX_HISTORY, np.int32, 1))\\n@@\\n             numerics.append(np.asarray([\\n@@\\n             ], np.float32))\\n+            infer_flags.append(cutoff == end)\\n             if cutoff == end:\\n                 target_lists.append(np.empty(0, np.int32))\\n                 target_gains.append(np.empty(0, np.float32))\\n+                infer_uids.append(uid)\\n                 continue\\n@@\\n-    is_infer = lengths == 0\\n+    is_infer = np.asarray(infer_flags, dtype=bool)\\n@@\\n-    # recover context uids: construction produces weeks+1 contexts/user unless empty history\\n-    # Re-run order cheaply from target uids; all target users have sufficient history here.\\n-    user_order = pd.read_parquet(DATA / \\\"target_users.parquet\\\").uid.to_numpy(np.int64)\\n+    user_order = pd.read_parquet(DATA / \\\"target_users.parquet\\\").uid.to_numpy(np.int64)\\n@@\\n-        target_offsets=offsets, targets=flat_targets, target_gains=flat_gains, infer_uids=user_order,\\n+        target_offsets=offsets, targets=flat_targets, target_gains=flat_gains, infer_uids=np.asarray(infer_uids, np.int64),\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:36:40.193Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 33,
      "role": "agent",
      "timestamp": "2026-08-31T18:36:47.411Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:36:47.411Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:36:52.388Z",
          "callId": "call_ohuMmu33HKDpSuogLSbORpG9",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python -m py_compile /app/solution/model.py /app/solution/train_ranker.py /app/solution/build_popularity.py && /usr/bin/time -f 'elapsed=%E maxrss=%MKB' /opt/task-venv/bin/python /app/solution/train_ranker.py preprocess --stage validation --weeks 6 --output /app/solution/validation_cache.npz\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:36:52.564Z",
            "content": "Script completed\nWall time 0.2 seconds\nOutput:\n\n/bin/sh: 1: /usr/bin/time: not found\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 34,
      "role": "agent",
      "timestamp": "2026-08-31T18:36:54.285Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:36:54.285Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:36:57.512Z",
          "callId": "call_v6sJzKjxmipvo9Fc6MMAGebK",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py preprocess --stage validation --weeks 6 --output /app/solution/validation_cache.npz\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:37:08.531Z",
            "content": "Script running with cell ID 19\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 35,
      "role": "agent",
      "timestamp": "2026-08-31T18:37:10.181Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:37:10.181Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:37:10.990Z",
          "callId": "call_Kaj1nnVKWDXIci9n6LMJ1tlv",
          "name": "wait",
          "input": {
            "cell_id": "19",
            "yield_time_ms": 30000,
            "max_tokens": 20000
          },
          "result": {
            "timestamp": "2026-08-31T18:37:27.693Z",
            "content": "Script completed\nWall time 16.7 seconds\nOutput:\n\n/app/solution/train_ranker.py:120: RuntimeWarning: overflow encountered in exp\n  short_w = base * np.exp(-(cutoff - last_time) / (18 * DAY))\n/app/solution/train_ranker.py:130: RuntimeWarning: overflow encountered in cast\n  lw[ix], sw[ix] = long_w, short_w\n/app/solution/train_ranker.py:138: RuntimeWarning: overflow encountered in cast\n  return unique.astype(np.int32), long_w.astype(np.float32), short_w.astype(np.float32), mask\npreprocessed 1,500 users\n\nSESSION_ID=62573",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 36,
      "role": "agent",
      "timestamp": "2026-08-31T18:37:33.017Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:37:33.017Z",
          "text": ""
        }
      ]
    },
    {
      "id": 37,
      "role": "agent",
      "timestamp": "2026-08-31T18:37:35.513Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:37:35.513Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:37:37.748Z",
          "text": "The first streaming pass exposed an unsigned-timestamp arithmetic issue in recency decay; I’m correcting that before training so old events cannot overflow their weights. The event scan itself is progressing normally and remains memory-bounded by one user plus compact cached contexts."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:37:39.387Z",
          "callId": "call_CceCZH7yEv3XBDhl0DgOw4KC",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:62573,chars:\"\\u0003\",yield_time_ms:1000,max_output_tokens:5000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:37:40.136Z",
            "content": "Script completed\nWall time 0.7 seconds\nOutput:\n\nTraceback (most recent call last):\n  File \"/app/solution/train_ranker.py\", line 410, in <module>\n    build_cache(args.stage, args.output, args.weeks)\n  File \"/app/solution/train_ranker.py\", line 199, in build_cache\n    disliked = active_items(user_dislikes, cutoff, item_map)\n               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/app/solution/train_ranker.py\", line 78, in active_items\n    rows = events[events.timestamp < cutoff]\n                  ^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/core/ops/common.py\", line 62, in new_method\n    @wraps(method)\n\nKeyboardInterrupt\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 38,
      "role": "agent",
      "timestamp": "2026-08-31T18:37:49.889Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:37:49.889Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:37:52.703Z",
          "callId": "call_BboVnZL4S2SODF7AsZ4BqsQh",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Update File: /app/solution/train_ranker.py\\n@@\\n def select_history(\\n@@\\n ) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:\\n+    timestamps = timestamps.astype(np.int64, copy=False)\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:37:52.758Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 39,
      "role": "agent",
      "timestamp": "2026-08-31T18:37:55.241Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:37:55.241Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:37:58.373Z",
          "callId": "call_ZXIon89FIOaMI0hLNogixdPW",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py preprocess --stage validation --weeks 6 --output /app/solution/validation_cache.npz\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:38:09.394Z",
            "content": "Script running with cell ID 22\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 40,
      "role": "agent",
      "timestamp": "2026-08-31T18:38:11.357Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:38:11.357Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:38:12.215Z",
          "callId": "call_adP5we0kyRegoaTH20e2EHcX",
          "name": "wait",
          "input": {
            "cell_id": "22",
            "yield_time_ms": 30000,
            "max_tokens": 20000
          },
          "result": {
            "timestamp": "2026-08-31T18:38:28.553Z",
            "content": "Script completed\nWall time 16.3 seconds\nOutput:\n\npreprocessed 1,500 users\n\nSESSION_ID=54126",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 41,
      "role": "agent",
      "timestamp": "2026-08-31T18:38:30.598Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:38:30.598Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:38:32.455Z",
          "callId": "call_uM7E0UD7nrYOozT4G3z1oXkg",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:54126,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:38:43.473Z",
            "content": "Script running with cell ID 23\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 42,
      "role": "agent",
      "timestamp": "2026-08-31T18:38:45.549Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:38:45.549Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:38:46.429Z",
          "callId": "call_ohn5W2sAwIeux62qjvHG81s3",
          "name": "wait",
          "input": {
            "cell_id": "23",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:39:02.476Z",
            "content": "Script completed\nWall time 16.0 seconds\nOutput:\n\npreprocessed 3,000 users\n\nSESSION_ID=54126",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 43,
      "role": "agent",
      "timestamp": "2026-08-31T18:39:04.066Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:39:04.066Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:39:05.966Z",
          "callId": "call_1XMucVcLIRyq4elN3G6T9gVN",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:54126,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:39:16.984Z",
            "content": "Script running with cell ID 24\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 44,
      "role": "agent",
      "timestamp": "2026-08-31T18:39:19.263Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:39:19.263Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:39:20.230Z",
          "callId": "call_ZAoDmwIO8wzfZiHUHTPiWeb0",
          "name": "wait",
          "input": {
            "cell_id": "24",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:39:35.988Z",
            "content": "Script completed\nWall time 15.8 seconds\nOutput:\n\npreprocessed 4,500 users\npreprocessed 6,000 users\n\nSESSION_ID=54126",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 45,
      "role": "agent",
      "timestamp": "2026-08-31T18:39:38.153Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:39:38.153Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:39:39.572Z",
          "callId": "call_anmTADn7tQ60xyD6iXgTd4Xb",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:54126,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:39:50.591Z",
            "content": "Script running with cell ID 25\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 46,
      "role": "agent",
      "timestamp": "2026-08-31T18:39:52.117Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:39:52.117Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:39:52.894Z",
          "callId": "call_pFpalgmmyKHwb3A897Hze7DO",
          "name": "wait",
          "input": {
            "cell_id": "25",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:40:04.676Z",
            "content": "Script completed\nWall time 11.8 seconds\nOutput:\n\npreprocessed 7,500 users\npreprocessed 9,000 users\nTraceback (most recent call last):\n  File \"/app/solution/train_ranker.py\", line 411, in <module>\n    build_cache(args.stage, args.output, args.weeks)\n  File \"/app/solution/train_ranker.py\", line 258, in build_cache\n    raise RuntimeError(f\"expected {len(user_order)} inference contexts, got {infer_count}\")\nRuntimeError: expected 8456 inference contexts, got 8449\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 47,
      "role": "agent",
      "timestamp": "2026-08-31T18:40:11.361Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:40:11.361Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:40:13.986Z",
          "callId": "call_3eFzwFFx1kDNagsYd1TlFscP",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Update File: /app/solution/train_ranker.py\\n@@\\n-            if not len(hist):\\n-                continue\\n             histories.append(pad(hist, MAX_HISTORY, np.int32, 1))\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:40:14.037Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 48,
      "role": "agent",
      "timestamp": "2026-08-31T18:40:15.659Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:40:15.659Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:40:18.787Z",
          "callId": "call_JNeCHxIsndRsYxAyVOmpRSta",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py preprocess --stage validation --weeks 6 --output /app/solution/validation_cache.npz\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:40:29.806Z",
            "content": "Script running with cell ID 27\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 49,
      "role": "agent",
      "timestamp": "2026-08-31T18:40:31.463Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:40:31.463Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:40:32.227Z",
          "callId": "call_m8lLifxRvXPEiZrkSJWt1Bc1",
          "name": "wait",
          "input": {
            "cell_id": "27",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:40:48.967Z",
            "content": "Script completed\nWall time 16.7 seconds\nOutput:\n\npreprocessed 1,500 users\n\nSESSION_ID=14477",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 50,
      "role": "agent",
      "timestamp": "2026-08-31T18:40:52.189Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:40:52.189Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:40:53.781Z",
          "callId": "call_7j03gbOCZecYlcB4NFWU6F07",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:14477,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:41:04.799Z",
            "content": "Script running with cell ID 28\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 51,
      "role": "agent",
      "timestamp": "2026-08-31T18:41:07.733Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:41:07.733Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:41:08.534Z",
          "callId": "call_aRw9zKHNVv0DuTlXn3yapbSn",
          "name": "wait",
          "input": {
            "cell_id": "28",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:41:23.802Z",
            "content": "Script completed\nWall time 15.3 seconds\nOutput:\n\npreprocessed 3,000 users\n\nSESSION_ID=14477",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 52,
      "role": "agent",
      "timestamp": "2026-08-31T18:41:25.363Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:41:25.363Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:41:27.217Z",
          "callId": "call_u4i6HDBUCA6iucpYlMvk5NUM",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:14477,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:41:38.236Z",
            "content": "Script running with cell ID 29\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 53,
      "role": "agent",
      "timestamp": "2026-08-31T18:41:41.118Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:41:41.118Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:41:41.851Z",
          "callId": "call_vp3xJGmnalWyASpq8YjQyqNb",
          "name": "wait",
          "input": {
            "cell_id": "29",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:41:57.244Z",
            "content": "Script completed\nWall time 15.4 seconds\nOutput:\n\npreprocessed 4,500 users\npreprocessed 6,000 users\n\nSESSION_ID=14477",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 54,
      "role": "agent",
      "timestamp": "2026-08-31T18:42:01.198Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:42:01.198Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:42:03.074Z",
          "callId": "call_R1VwU0PT8ai0G8drtQrh0zlu",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:14477,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:42:14.095Z",
            "content": "Script running with cell ID 30\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 55,
      "role": "agent",
      "timestamp": "2026-08-31T18:42:15.983Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:42:15.983Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:42:16.814Z",
          "callId": "call_m9j39ZHrhKUK30bKKP3y6lVI",
          "name": "wait",
          "input": {
            "cell_id": "30",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:42:32.691Z",
            "content": "Script completed\nWall time 15.9 seconds\nOutput:\n\npreprocessed 7,500 users\npreprocessed 9,000 users\n{\"cache\": \"/app/solution/validation_cache.npz\", \"contexts\": 59192, \"train_contexts\": 24594, \"targets\": 234017}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 56,
      "role": "agent",
      "timestamp": "2026-08-31T18:42:35.407Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:42:35.407Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:42:45.035Z",
          "callId": "call_f9ZKV4GQ2Pe4vMnrFeIju7Zp",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"ls -lh /app/solution/validation_cache.npz && /opt/task-venv/bin/python - <<'PY'\\nimport numpy as np\\nz=np.load('/app/solution/validation_cache.npz')\\nfor k in z.files:\\n x=z[k]; print(k,x.shape,x.dtype,'finite' if x.dtype.kind=='f' and np.isfinite(x).all() else '')\\nprint('uid aligned',np.array_equal(z['infer_uids'],np.load('/task/data/validation_eligible_candidates.npz')['uids']))\\nprint('target context label quantiles',np.quantile(np.diff(z['target_offsets']),[0,.25,.5,.75,.9,.99,1]))\\nPY\\n/opt/task-venv/bin/python /app/solution/train_ranker.py train --cache /app/solution/validation_cache.npz --model /app/solution/validation_model.pt --epochs 14 --seed 2026 --dim 64\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:42:56.056Z",
            "content": "Script running with cell ID 31\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 57,
      "role": "agent",
      "timestamp": "2026-08-31T18:42:57.832Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:42:57.832Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:42:58.780Z",
          "callId": "call_rNwJJ4x1BLKathiOJy5OcBPn",
          "name": "wait",
          "input": {
            "cell_id": "31",
            "yield_time_ms": 30000,
            "max_tokens": 20000
          },
          "result": {
            "timestamp": "2026-08-31T18:43:15.219Z",
            "content": "Script completed\nWall time 16.4 seconds\nOutput:\n\n-rw-r--r-- 1 agent agent 98M Aug 31 18:42 /app/solution/validation_cache.npz\nhistory (59192, 256) int32 \nlong (59192, 256) float32 finite\nshort (59192, 256) float32 finite\nnegative (59192, 64) int32 \nnegative_weight (59192, 64) float32 finite\nnumeric (59192, 4) float32 finite\ntrain_rows (24594,) int32 \ninfer_rows (8456,) int32 \ntarget_offsets (24595,) int64 \ntargets (234017,) int32 \ntarget_gains (234017,) float32 finite\ninfer_uids (8456,) int64 \nuid aligned True\ntarget context label quantiles [  1.   2.   4.  11.  22.  76. 349.]\n/app/solution/train_ranker.py:334: UserWarning: Converting a tensor with requires_grad=True to a scalar may lead to unexpected behavior.\nConsider using tensor.detach() first. (Triggered internally at /pytorch/torch/csrc/autograd/generated/python_variable_methods.cpp:835.)\n  total += float(loss); batches += 1\n\nSESSION_ID=81188",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 58,
      "role": "agent",
      "timestamp": "2026-08-31T18:43:17.302Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:43:17.302Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:43:19.988Z",
          "text": "Preprocessing produced 24,594 nonempty temporal training contexts and 234,017 unseen organic positives across six rolling weeks; all 8,456 inference users align exactly with eligibility. The model is now training with mixed popularity-shaped and uniform sampled negatives, which preserves the production-friendly event/sampling path and avoids any global interaction matrix."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:43:21.895Z",
          "callId": "call_OuZ4dIyokT4WoTVbYa5MQk7u",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:81188,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:43:32.917Z",
            "content": "Script running with cell ID 32\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 59,
      "role": "agent",
      "timestamp": "2026-08-31T18:43:34.477Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:43:34.477Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:43:35.298Z",
          "callId": "call_OTYQB7vaSzGykq9O1LQHRHsp",
          "name": "wait",
          "input": {
            "cell_id": "32",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:43:51.920Z",
            "content": "Script completed\nWall time 16.6 seconds\nOutput:\n\n\nSESSION_ID=81188",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 60,
      "role": "agent",
      "timestamp": "2026-08-31T18:43:53.738Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:43:53.738Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:43:55.603Z",
          "callId": "call_NJ6pjoB71ztvovpmN2xiAgF2",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:81188,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:44:06.633Z",
            "content": "Script running with cell ID 33\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 61,
      "role": "agent",
      "timestamp": "2026-08-31T18:44:09.152Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:44:09.152Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:44:09.953Z",
          "callId": "call_8gvNJFCBNwX81iidRT3W8Fyw",
          "name": "wait",
          "input": {
            "cell_id": "33",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:44:25.636Z",
            "content": "Script completed\nWall time 15.7 seconds\nOutput:\n\nepoch 01 loss=0.58880\n\nSESSION_ID=81188",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 62,
      "role": "agent",
      "timestamp": "2026-08-31T18:44:28.586Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:44:28.586Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:44:30.567Z",
          "callId": "call_W9CHuDs1p4d67CaR6o04m2vS",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:81188,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:44:41.586Z",
            "content": "Script running with cell ID 34\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 63,
      "role": "agent",
      "timestamp": "2026-08-31T18:44:43.153Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:44:43.153Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:44:43.909Z",
          "callId": "call_xRT0Qruc3jL1CGVM1OY6YbgE",
          "name": "wait",
          "input": {
            "cell_id": "34",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:45:00.589Z",
            "content": "Script completed\nWall time 16.7 seconds\nOutput:\n\n\nSESSION_ID=81188",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 64,
      "role": "agent",
      "timestamp": "2026-08-31T18:45:04.231Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:45:04.231Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:45:06.134Z",
          "callId": "call_nM8EhU7RYQOAX15uSdepURr6",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:81188,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:45:17.155Z",
            "content": "Script running with cell ID 35\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 65,
      "role": "agent",
      "timestamp": "2026-08-31T18:45:19.128Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:45:19.128Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:45:19.925Z",
          "callId": "call_r8LVkQOC9qnDag7FEaCgPdQ3",
          "name": "wait",
          "input": {
            "cell_id": "35",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:45:36.159Z",
            "content": "Script completed\nWall time 16.2 seconds\nOutput:\n\n\nSESSION_ID=81188",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 66,
      "role": "agent",
      "timestamp": "2026-08-31T18:45:37.690Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:45:37.690Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:45:39.590Z",
          "callId": "call_hPbZ9GBLUzGExk0Fc2ex4aqs",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:81188,chars:\"\",yield_time_ms:30000,max_output_tokens:10000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:45:50.608Z",
            "content": "Script running with cell ID 36\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 67,
      "role": "agent",
      "timestamp": "2026-08-31T18:45:53.426Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:45:53.426Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:45:54.185Z",
          "callId": "call_2D3porwlSnqlhzO54N05b4le",
          "name": "wait",
          "input": {
            "cell_id": "36",
            "yield_time_ms": 30000,
            "max_tokens": 10000
          },
          "result": {
            "timestamp": "2026-08-31T18:46:09.611Z",
            "content": "Script completed\nWall time 15.4 seconds\nOutput:\n\nepoch 02 loss=0.51000\n\nSESSION_ID=81188",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 68,
      "role": "agent",
      "timestamp": "2026-08-31T18:46:21.604Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:46:21.604Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:46:23.124Z",
          "callId": "call_9C45LwF55oKLKwDMOqY2uuVo",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:81188,chars:\"\\u0003\",yield_time_ms:1000,max_output_tokens:5000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:46:23.562Z",
            "content": "Script completed\nWall time 0.4 seconds\nOutput:\n\nTraceback (most recent call last):\n  File \"/app/solution/train_ranker.py\", line 411, in <module>\n    train_model(args.cache, args.model, args.epochs, args.seed, args.dim)\n  File \"/app/solution/train_ranker.py\", line 320, in train_model\n    tensor_rows(cache, \"short\", data_rows), tensor_rows(cache, \"negative\", data_rows),\n    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/app/solution/train_ranker.py\", line 278, in tensor_rows\n    return torch.from_numpy(cache[name][rows]).to(device)\n                            ~~~~~^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/numpy/lib/_npyio_impl.py\", line 254, in __getitem__\n    return format.read_array(bytes,\n           ^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/numpy/lib/format.py\", line 851, in read_array\n    data = _read_bytes(fp, read_size, \"array data\")\n           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/numpy/lib/format.py\", line 986, in _read_bytes\n    r = fp.read(size - len(data))\n        ^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.12/zipfile/__init__.py\", line 1008, in read\n    data = self._read1(n)\n           ^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.12/zipfile/__init__.py\", line 1098, in _read1\n    self._update_crc(data)\n  File \"/usr/local/lib/python3.12/zipfile/__init__.py\", line 1023, in _update_crc\n    self._running_crc = crc32(newdata, self._running_crc)\n                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\nKeyboardInterrupt\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 69,
      "role": "agent",
      "timestamp": "2026-08-31T18:46:29.062Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:46:29.062Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:46:36.381Z",
          "callId": "call_GYVGPnZ7ZA6zlrA3I39GYTZB",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Update File: /app/solution/train_ranker.py\\n@@\\n def train_model(cache_path: Path, model_path: Path, epochs: int, seed: int, dim: int) -> None:\\n     seed_everything(seed)\\n-    torch.set_num_threads(min(8, torch.get_num_threads()))\\n-    cache = np.load(cache_path)\\n+    torch.set_num_threads(8)\\n+    with np.load(cache_path) as archive:\\n+        cache = {name: archive[name] for name in archive.files}\\n@@\\n-    batch_size, negatives_per = 192, 40\\n+    batch_size, negatives_per = 256, 32\\n@@\\n-            total += float(loss); batches += 1\\n+            total += float(loss.detach()); batches += 1\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:46:36.457Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 70,
      "role": "agent",
      "timestamp": "2026-08-31T18:46:40.441Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:46:40.441Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:46:44.154Z",
          "callId": "call_yMNeUmsLJWJElYuaOLb0DEEv",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py train --cache /app/solution/validation_cache.npz --model /app/solution/validation_model.pt --epochs 10 --seed 2026 --dim 64\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:46:55.182Z",
            "content": "Script running with cell ID 39\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 71,
      "role": "agent",
      "timestamp": "2026-08-31T18:46:56.934Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:46:56.934Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:46:57.675Z",
          "callId": "call_h7AH6l40Uvq9JyNMDhC0ndHh",
          "name": "wait",
          "input": {
            "cell_id": "39",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:47:14.351Z",
            "content": "Script completed\nWall time 16.7 seconds\nOutput:\n\nepoch 01 loss=0.59207\nepoch 02 loss=0.52318\nepoch 03 loss=0.46337\n\nSESSION_ID=43340",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 72,
      "role": "agent",
      "timestamp": "2026-08-31T18:47:16.530Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:47:16.530Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:47:18.397Z",
          "callId": "call_6qLN7wLn39RWibIyq82ldDyY",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:43340,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:47:29.433Z",
            "content": "Script running with cell ID 40\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 73,
      "role": "agent",
      "timestamp": "2026-08-31T18:47:31.214Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:47:31.214Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:47:32.033Z",
          "callId": "call_fzQKFyjFKMcHdFJFUsEjXx5D",
          "name": "wait",
          "input": {
            "cell_id": "40",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:47:48.445Z",
            "content": "Script completed\nWall time 16.4 seconds\nOutput:\n\nepoch 04 loss=0.41948\nepoch 05 loss=0.38892\nepoch 06 loss=0.36797\nepoch 07 loss=0.35050\nepoch 08 loss=0.33681\nepoch 09 loss=0.32130\n\nSESSION_ID=43340",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 74,
      "role": "agent",
      "timestamp": "2026-08-31T18:47:50.145Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:47:50.145Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:47:52.206Z",
          "callId": "call_uxkkLZ5WmgyYaesEwX3qJaBx",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:43340,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:47:52.274Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\nepoch 10 loss=0.31241\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 75,
      "role": "agent",
      "timestamp": "2026-08-31T18:47:57.141Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:47:57.141Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:48:01.317Z",
          "callId": "call_DWTEyI2ikfKsnUC8NQ04SojO",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Update File: /app/solution/train_ranker.py\\n@@\\n def rank(cache_path: Path, model_path: Path, stage: str, output: Path, pop_blend: float) -> None:\\n-    cache = np.load(cache_path)\\n+    with np.load(cache_path) as archive:\\n+        cache = {name: archive[name] for name in archive.files}\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:48:01.384Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 76,
      "role": "agent",
      "timestamp": "2026-08-31T18:48:07.079Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:48:07.079Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:48:10.369Z",
          "text": "Training is now efficient after caching the compressed arrays once in memory; the ten-epoch loss fell from 0.592 to 0.312. I’m generating cutoff-valid rankings over all 30,000 candidates and testing only a small popularity-blend grid—the tower score remains the user/item dot product, while the blend check tells me whether the learned item tower already calibrated head-item prevalence sufficiently."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:48:16.662Z",
          "callId": "call_3MmGFY8MMEZG447ppqJkChHs",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"for b in 0 0.02 0.05 0.08 0.12 0.18; do /opt/task-venv/bin/python /app/solution/train_ranker.py rank --cache /app/solution/validation_cache.npz --model /app/solution/validation_model.pt --stage validation --pop-blend \\\"$b\\\" --output \\\"/app/solution/validation_b${b}.parquet\\\"; /opt/task-venv/bin/python /task/evaluate_public.py \\\"/app/solution/validation_b${b}.parquet\\\"; done\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:48:27.691Z",
            "content": "Script running with cell ID 43\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 77,
      "role": "agent",
      "timestamp": "2026-08-31T18:48:29.228Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:48:29.228Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:48:30.077Z",
          "callId": "call_2oldfjtM1bcUtTA9ZUDBweCh",
          "name": "wait",
          "input": {
            "cell_id": "43",
            "yield_time_ms": 30000,
            "max_tokens": 20000
          },
          "result": {
            "timestamp": "2026-08-31T18:48:46.850Z",
            "content": "Script completed\nWall time 16.8 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation_b0.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.014898,\n    \"quality_users\": 4263\n  }\n}\n\nSESSION_ID=7674",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 78,
      "role": "agent",
      "timestamp": "2026-08-31T18:48:51.017Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:48:51.017Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:48:52.888Z",
          "callId": "call_SIt6lQaqaLReNwgW1oIAEpJU",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:7674,chars:\"\",yield_time_ms:30000,max_output_tokens:20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:49:03.916Z",
            "content": "Script running with cell ID 44\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 79,
      "role": "agent",
      "timestamp": "2026-08-31T18:49:05.869Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:49:05.869Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:49:06.537Z",
          "callId": "call_ghghI3pFrXYdmiWDJoZoiWYb",
          "name": "wait",
          "input": {
            "cell_id": "44",
            "yield_time_ms": 30000,
            "max_tokens": 20000
          },
          "result": {
            "timestamp": "2026-08-31T18:49:22.916Z",
            "content": "Script completed\nWall time 16.4 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation_b0.02.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.016418,\n    \"quality_users\": 4263\n  }\n}\n{\n  \"model\": \"/app/solution/validation_b0.05.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.018334,\n    \"quality_users\": 4263\n  }\n}\n\nSESSION_ID=7674",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 80,
      "role": "agent",
      "timestamp": "2026-08-31T18:49:25.571Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:49:25.571Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:49:27.268Z",
          "callId": "call_eWvCcgfFaDWK8sF5ZGPb4iMf",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:7674,chars:\"\",yield_time_ms:30000,max_output_tokens:20000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:49:38.286Z",
            "content": "Script running with cell ID 45\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 81,
      "role": "agent",
      "timestamp": "2026-08-31T18:49:39.892Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:49:39.892Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:49:40.633Z",
          "callId": "call_cTMYeR2melb7z3wCdugtI9DY",
          "name": "wait",
          "input": {
            "cell_id": "45",
            "yield_time_ms": 30000,
            "max_tokens": 20000
          },
          "result": {
            "timestamp": "2026-08-31T18:49:57.265Z",
            "content": "Script completed\nWall time 16.6 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation_b0.08.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.017738,\n    \"quality_users\": 4263\n  }\n}\n{\n  \"model\": \"/app/solution/validation_b0.12.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.015999,\n    \"quality_users\": 4263\n  }\n}\n{\n  \"model\": \"/app/solution/validation_b0.18.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.013797,\n    \"quality_users\": 4263\n  }\n}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 82,
      "role": "agent",
      "timestamp": "2026-08-31T18:50:16.955Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:50:16.955Z",
          "text": ""
        }
      ]
    },
    {
      "id": 83,
      "role": "agent",
      "timestamp": "2026-08-31T18:50:22.029Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:50:22.029Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:50:25.298Z",
          "text": "The personalized tower reaches 0.018334 at a 0.05 popularity blend, versus 0.010710 for popularity alone (about a 71% lift). I’m expanding the rolling temporal supervision from six to fourteen weeks; this should improve collaborative track geometry without changing inference cost or violating the temporal boundary. The current 0.018334 ranking remains saved as the fallback."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:50:28.459Z",
          "callId": "call_y3aA7d5S4UaajHCWmICToZ3u",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py preprocess --stage validation --weeks 14 --output /app/solution/validation_cache_w14.npz\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:50:39.480Z",
            "content": "Script running with cell ID 46\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 84,
      "role": "agent",
      "timestamp": "2026-08-31T18:50:43.245Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:50:43.245Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:50:44.043Z",
          "callId": "call_A2sxHe2vUzlMoEhgvhpADFvR",
          "name": "wait",
          "input": {
            "cell_id": "46",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:50:58.639Z",
            "content": "Script completed\nWall time 14.6 seconds\nOutput:\n\n\nSESSION_ID=40623",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 85,
      "role": "agent",
      "timestamp": "2026-08-31T18:51:00.109Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:51:00.109Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:51:02.003Z",
          "callId": "call_lsrHtmXnVa4jBDB4SoGacYtB",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:40623,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:51:13.022Z",
            "content": "Script running with cell ID 47\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 86,
      "role": "agent",
      "timestamp": "2026-08-31T18:51:14.930Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:51:14.930Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:51:15.678Z",
          "callId": "call_Go6Up96X194LEpYy56L6RQUL",
          "name": "wait",
          "input": {
            "cell_id": "47",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:51:32.025Z",
            "content": "Script completed\nWall time 16.3 seconds\nOutput:\n\npreprocessed 1,500 users\n\nSESSION_ID=40623",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 87,
      "role": "agent",
      "timestamp": "2026-08-31T18:51:35.088Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:51:35.088Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:51:36.874Z",
          "callId": "call_JZ4bMot6VSdVtz192PqxtaCc",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:40623,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:51:47.896Z",
            "content": "Script running with cell ID 48\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 88,
      "role": "agent",
      "timestamp": "2026-08-31T18:51:49.710Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:51:49.710Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:51:50.279Z",
          "callId": "call_xIIJvwGDU5ZAPCvrO4RQWn9l",
          "name": "wait",
          "input": {
            "cell_id": "48",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:52:06.900Z",
            "content": "Script completed\nWall time 16.6 seconds\nOutput:\n\npreprocessed 3,000 users\n\nSESSION_ID=40623",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 89,
      "role": "agent",
      "timestamp": "2026-08-31T18:52:08.468Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:52:08.468Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:52:10.271Z",
          "callId": "call_4jAKDXaBzUO3y4lYXySJhO1T",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:40623,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:52:21.293Z",
            "content": "Script running with cell ID 49\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 90,
      "role": "agent",
      "timestamp": "2026-08-31T18:52:22.962Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:52:22.962Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:52:23.768Z",
          "callId": "call_c8xQGr5JCpRSQN8NzZnEnugl",
          "name": "wait",
          "input": {
            "cell_id": "49",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:52:40.296Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\npreprocessed 4,500 users\n\nSESSION_ID=40623",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 91,
      "role": "agent",
      "timestamp": "2026-08-31T18:52:41.847Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:52:41.847Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:52:43.693Z",
          "callId": "call_gWBWe1s7grGJZIEyE7ipKH54",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:40623,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:52:54.712Z",
            "content": "Script running with cell ID 50\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 92,
      "role": "agent",
      "timestamp": "2026-08-31T18:52:56.636Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:52:56.636Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:52:57.257Z",
          "callId": "call_Fu40zhyVTCi8e1ivMUati7oy",
          "name": "wait",
          "input": {
            "cell_id": "50",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:53:13.715Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\npreprocessed 6,000 users\n\nSESSION_ID=40623",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 93,
      "role": "agent",
      "timestamp": "2026-08-31T18:53:15.333Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:53:15.333Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:53:17.154Z",
          "callId": "call_cRQQOI0VUc5FUIEF5rR6X6dG",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:40623,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:53:28.176Z",
            "content": "Script running with cell ID 51\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 94,
      "role": "agent",
      "timestamp": "2026-08-31T18:53:29.793Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:53:29.793Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:53:30.527Z",
          "callId": "call_FigTBv13klyQ2MEAFgJmiNlN",
          "name": "wait",
          "input": {
            "cell_id": "51",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:53:47.180Z",
            "content": "Script completed\nWall time 16.7 seconds\nOutput:\n\npreprocessed 7,500 users\n\nSESSION_ID=40623",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 95,
      "role": "agent",
      "timestamp": "2026-08-31T18:53:48.768Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:53:48.768Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:53:50.612Z",
          "callId": "call_scV3KzHaNmKEDyEPYmSTNFNH",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:40623,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:54:01.630Z",
            "content": "Script running with cell ID 52\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 96,
      "role": "agent",
      "timestamp": "2026-08-31T18:54:03.202Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:54:03.202Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:54:03.974Z",
          "callId": "call_5tzWbJJSmSuKxutMEzvrLzZd",
          "name": "wait",
          "input": {
            "cell_id": "52",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:54:20.634Z",
            "content": "Script completed\nWall time 16.7 seconds\nOutput:\n\n\nSESSION_ID=40623",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 97,
      "role": "agent",
      "timestamp": "2026-08-31T18:54:22.112Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:54:22.112Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:54:23.988Z",
          "callId": "call_qrEek0uldGwkAY21D5gio7rc",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:40623,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:54:35.010Z",
            "content": "Script running with cell ID 53\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 98,
      "role": "agent",
      "timestamp": "2026-08-31T18:54:36.847Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:54:36.847Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:54:37.634Z",
          "callId": "call_hqfBUNnewk3Mdxrhvdmco3ih",
          "name": "wait",
          "input": {
            "cell_id": "53",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:54:44.458Z",
            "content": "Script completed\nWall time 6.8 seconds\nOutput:\n\npreprocessed 9,000 users\n{\"cache\": \"/app/solution/validation_cache_w14.npz\", \"contexts\": 126840, \"train_contexts\": 52461, \"targets\": 492274}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 99,
      "role": "agent",
      "timestamp": "2026-08-31T18:54:47.699Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:54:47.699Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:54:51.526Z",
          "callId": "call_xFM22fyVtQRpoEYrovCg3HZT",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py train --cache /app/solution/validation_cache_w14.npz --model /app/solution/validation_model_w14.pt --epochs 10 --seed 2026 --dim 64\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:55:02.549Z",
            "content": "Script running with cell ID 54\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 100,
      "role": "agent",
      "timestamp": "2026-08-31T18:55:04.945Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:55:04.945Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:55:05.453Z",
          "callId": "call_bQHxiKl8QyfMH3hFOEHfTcky",
          "name": "wait",
          "input": {
            "cell_id": "54",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:55:21.717Z",
            "content": "Script completed\nWall time 16.3 seconds\nOutput:\n\nepoch 01 loss=0.56491\n\nSESSION_ID=83725",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 101,
      "role": "agent",
      "timestamp": "2026-08-31T18:55:23.880Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:55:23.880Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:55:26.197Z",
          "callId": "call_L0EUORlgRrWN25RyTKRhmS90",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:83725,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:55:37.238Z",
            "content": "Script running with cell ID 55\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 102,
      "role": "agent",
      "timestamp": "2026-08-31T18:55:39.033Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:55:39.033Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:55:39.842Z",
          "callId": "call_cmwbo0KD7zi9084t8PmppjxQ",
          "name": "wait",
          "input": {
            "cell_id": "55",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:55:56.252Z",
            "content": "Script completed\nWall time 16.4 seconds\nOutput:\n\nepoch 02 loss=0.49672\nepoch 03 loss=0.44811\nepoch 04 loss=0.41821\n\nSESSION_ID=83725",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 103,
      "role": "agent",
      "timestamp": "2026-08-31T18:55:58.476Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:55:58.476Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:56:00.338Z",
          "callId": "call_PqQqEJf42Qh9s1ogGbaTVIqY",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:83725,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:56:11.377Z",
            "content": "Script running with cell ID 56\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 104,
      "role": "agent",
      "timestamp": "2026-08-31T18:56:13.403Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:56:13.403Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:56:14.167Z",
          "callId": "call_Uz865uorMB7xuoV8iDidC049",
          "name": "wait",
          "input": {
            "cell_id": "56",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:56:30.390Z",
            "content": "Script completed\nWall time 16.2 seconds\nOutput:\n\nepoch 05 loss=0.39901\nepoch 06 loss=0.38602\nepoch 07 loss=0.36958\n\nSESSION_ID=83725",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 105,
      "role": "agent",
      "timestamp": "2026-08-31T18:56:32.665Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:56:32.665Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:56:34.532Z",
          "callId": "call_n06P5NnD2lsKZlCVdnnvP18w",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:83725,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:56:45.557Z",
            "content": "Script running with cell ID 57\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 106,
      "role": "agent",
      "timestamp": "2026-08-31T18:56:47.383Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:56:47.383Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:56:48.206Z",
          "callId": "call_19xZTSbaKOo9UFZtg1t09iNK",
          "name": "wait",
          "input": {
            "cell_id": "57",
            "yield_time_ms": 30000,
            "max_tokens": 12000
          },
          "result": {
            "timestamp": "2026-08-31T18:57:04.560Z",
            "content": "Script completed\nWall time 16.4 seconds\nOutput:\n\nepoch 08 loss=0.35282\nepoch 09 loss=0.33951\n\nSESSION_ID=83725",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 107,
      "role": "agent",
      "timestamp": "2026-08-31T18:57:06.256Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:57:06.256Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:57:08.103Z",
          "callId": "call_KNHfbB7zOwaua0DvOCZEAbrB",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:83725,chars:\"\",yield_time_ms:30000,max_output_tokens:12000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:57:08.194Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\nepoch 10 loss=0.32587\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 108,
      "role": "agent",
      "timestamp": "2026-08-31T18:57:10.121Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:57:10.121Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:57:16.447Z",
          "callId": "call_1n99sSPhvsdZGE1KHGUG1T83",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"for b in 0.03 0.045 0.06 0.075; do /opt/task-venv/bin/python /app/solution/train_ranker.py rank --cache /app/solution/validation_cache_w14.npz --model /app/solution/validation_model_w14.pt --stage validation --pop-blend \\\"$b\\\" --output \\\"/app/solution/validation_w14_b${b}.parquet\\\"; /opt/task-venv/bin/python /task/evaluate_public.py \\\"/app/solution/validation_w14_b${b}.parquet\\\"; done\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:57:27.473Z",
            "content": "Script running with cell ID 59\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 109,
      "role": "agent",
      "timestamp": "2026-08-31T18:57:29.134Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:57:29.134Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:57:29.967Z",
          "callId": "call_SxVXHsC380Vd9xJz8cH6CCZ4",
          "name": "wait",
          "input": {
            "cell_id": "59",
            "yield_time_ms": 30000,
            "max_tokens": 16000
          },
          "result": {
            "timestamp": "2026-08-31T18:57:46.633Z",
            "content": "Script completed\nWall time 16.7 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation_w14_b0.03.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.019052,\n    \"quality_users\": 4263\n  }\n}\n\nSESSION_ID=54812",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 110,
      "role": "agent",
      "timestamp": "2026-08-31T18:57:48.239Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:57:48.239Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:57:50.165Z",
          "callId": "call_rGXyQkLPzzAV0tW4x09uUfuR",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:54812,chars:\"\",yield_time_ms:30000,max_output_tokens:16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:58:01.183Z",
            "content": "Script running with cell ID 60\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 111,
      "role": "agent",
      "timestamp": "2026-08-31T18:58:02.788Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:58:02.788Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:58:03.606Z",
          "callId": "call_FvacgqLDxUqdw8kZyRj1X40k",
          "name": "wait",
          "input": {
            "cell_id": "60",
            "yield_time_ms": 30000,
            "max_tokens": 16000
          },
          "result": {
            "timestamp": "2026-08-31T18:58:20.187Z",
            "content": "Script completed\nWall time 16.6 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation_w14_b0.045.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.019178,\n    \"quality_users\": 4263\n  }\n}\n{\n  \"model\": \"/app/solution/validation_w14_b0.06.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.019164,\n    \"quality_users\": 4263\n  }\n}\n\nSESSION_ID=54812",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 112,
      "role": "agent",
      "timestamp": "2026-08-31T18:58:21.897Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:58:21.897Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:58:23.733Z",
          "callId": "call_v3VPTvuikWualqUUml2h3mGq",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:54812,chars:\"\",yield_time_ms:30000,max_output_tokens:16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:58:26.390Z",
            "content": "Script completed\nWall time 2.7 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation_w14_b0.075.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.018046,\n    \"quality_users\": 4263\n  }\n}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 113,
      "role": "agent",
      "timestamp": "2026-08-31T18:58:46.052Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:58:46.052Z",
          "text": ""
        }
      ]
    },
    {
      "id": 114,
      "role": "agent",
      "timestamp": "2026-08-31T18:58:54.444Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:58:54.444Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T18:58:57.317Z",
          "text": "Fourteen weeks improves the public score again to 0.019178, with the optimum centered tightly around a 0.045 calibration weight. I’m checking a second initialization for variance and possible ensemble gain; if it is not complementary, I’ll retain the stronger single model and proceed directly to the required train+validation refit."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:59:04.733Z",
          "callId": "call_ajkmcdcJ8TWZxXHATOrfouoB",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py train --cache /app/solution/validation_cache_w14.npz --model /app/solution/validation_model_w14_s314.pt --epochs 10 --seed 314 --dim 64 && /opt/task-venv/bin/python /app/solution/train_ranker.py rank --cache /app/solution/validation_cache_w14.npz --model /app/solution/validation_model_w14_s314.pt --stage validation --pop-blend 0.045 --output /app/solution/validation_w14_s314.parquet && /opt/task-venv/bin/python /task/evaluate_public.py /app/solution/validation_w14_s314.parquet\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:59:15.763Z",
            "content": "Script running with cell ID 62\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 115,
      "role": "agent",
      "timestamp": "2026-08-31T18:59:17.779Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:59:17.779Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:59:18.567Z",
          "callId": "call_yaNb4AViVymvm8MM4EXm0VWQ",
          "name": "wait",
          "input": {
            "cell_id": "62",
            "yield_time_ms": 30000,
            "max_tokens": 16000
          },
          "result": {
            "timestamp": "2026-08-31T18:59:34.931Z",
            "content": "Script completed\nWall time 16.4 seconds\nOutput:\n\nepoch 01 loss=0.56264\n\nSESSION_ID=87734",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 116,
      "role": "agent",
      "timestamp": "2026-08-31T18:59:36.766Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:59:36.766Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:59:38.619Z",
          "callId": "call_pO8dQYrv01JRZ6tUS7ZXTq79",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:87734,chars:\"\",yield_time_ms:30000,max_output_tokens:16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T18:59:49.669Z",
            "content": "Script running with cell ID 63\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 117,
      "role": "agent",
      "timestamp": "2026-08-31T18:59:51.335Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T18:59:51.335Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T18:59:52.121Z",
          "callId": "call_8IOd6Azg9gTc9NlVLxhRxGu2",
          "name": "wait",
          "input": {
            "cell_id": "63",
            "yield_time_ms": 30000,
            "max_tokens": 16000
          },
          "result": {
            "timestamp": "2026-08-31T19:00:08.681Z",
            "content": "Script completed\nWall time 16.6 seconds\nOutput:\n\nepoch 02 loss=0.49339\nepoch 03 loss=0.44482\nepoch 04 loss=0.41867\n\nSESSION_ID=87734",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 118,
      "role": "agent",
      "timestamp": "2026-08-31T19:00:10.203Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:00:10.203Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:00:12.118Z",
          "callId": "call_81DTyyqxVHPGY8bbHTgbMOtM",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:87734,chars:\"\",yield_time_ms:30000,max_output_tokens:16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:00:23.166Z",
            "content": "Script running with cell ID 64\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 119,
      "role": "agent",
      "timestamp": "2026-08-31T19:00:24.873Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:00:24.873Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:00:25.655Z",
          "callId": "call_qlfMzSMcSfzZYzNTWJOU7VYG",
          "name": "wait",
          "input": {
            "cell_id": "64",
            "yield_time_ms": 30000,
            "max_tokens": 16000
          },
          "result": {
            "timestamp": "2026-08-31T19:00:42.181Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\nepoch 05 loss=0.40006\nepoch 06 loss=0.38560\nepoch 07 loss=0.37323\n\nSESSION_ID=87734",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 120,
      "role": "agent",
      "timestamp": "2026-08-31T19:00:44.816Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:00:44.816Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:00:46.656Z",
          "callId": "call_KnFBQeTJipvJr2pHOJbIzvpA",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:87734,chars:\"\",yield_time_ms:30000,max_output_tokens:16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:00:57.701Z",
            "content": "Script running with cell ID 65\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 121,
      "role": "agent",
      "timestamp": "2026-08-31T19:00:59.412Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:00:59.412Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:01:00.153Z",
          "callId": "call_734voX885tw4GyHf2TjDFsJC",
          "name": "wait",
          "input": {
            "cell_id": "65",
            "yield_time_ms": 30000,
            "max_tokens": 16000
          },
          "result": {
            "timestamp": "2026-08-31T19:01:16.700Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\nepoch 08 loss=0.35850\nepoch 09 loss=0.34477\nepoch 10 loss=0.33173\n\nSESSION_ID=87734",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 122,
      "role": "agent",
      "timestamp": "2026-08-31T19:01:21.562Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:01:21.562Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:01:23.462Z",
          "callId": "call_5gSgPyzImWAfgw7K8i4FNtH9",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:87734,chars:\"\",yield_time_ms:30000,max_output_tokens:16000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:01:32.254Z",
            "content": "Script completed\nWall time 8.8 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation_w14_s314.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.018042,\n    \"quality_users\": 4263\n  }\n}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 123,
      "role": "agent",
      "timestamp": "2026-08-31T19:01:52.102Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:01:52.102Z",
          "text": ""
        }
      ]
    },
    {
      "id": 124,
      "role": "agent",
      "timestamp": "2026-08-31T19:02:05.857Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:02:05.857Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:02:33.128Z",
          "callId": "call_K5OlzGq3b5bPqo549ThDw5NM",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Update File: /app/solution/model.py\\n@@\\n class TwoTower(nn.Module):\\n@@\\n         self.item_tower = ItemTower(num_items, output_dim=output_dim)\\n+\\n+\\n+class CalibratedUserTower(nn.Module):\\n+    \\\"\\\"\\\"Deployment user tower with a constant coordinate for popularity calibration.\\\"\\\"\\\"\\n+\\n+    def __init__(self, base: UserTower):\\n+        super().__init__()\\n+        self.base = base\\n+\\n+    def forward(self, *args: torch.Tensor) -> torch.Tensor:\\n+        vector = self.base(*args)\\n+        return torch.cat([vector, torch.ones_like(vector[:, :1])], dim=1)\\n+\\n+\\n+class CalibratedItemTower(nn.Module):\\n+    \\\"\\\"\\\"Deployment item tower; its output remains independently precomputable.\\\"\\\"\\\"\\n+\\n+    def __init__(self, base: ItemTower, popularity: torch.Tensor, weight: float):\\n+        super().__init__()\\n+        self.base = base\\n+        self.register_buffer(\\\"popularity\\\", popularity)\\n+        self.weight = float(weight)\\n+\\n+    def forward(self, item_ids: torch.Tensor, features: torch.Tensor) -> torch.Tensor:\\n+        vector = self.base(item_ids, features)\\n+        coordinate = self.popularity[item_ids - 1].unsqueeze(-1) * self.weight\\n+        return torch.cat([vector, coordinate], dim=-1)\\n*** Update File: /app/solution/train_ranker.py\\n@@\\n-from model import TwoTower\\n+from model import CalibratedItemTower, CalibratedUserTower, TwoTower\\n@@\\n     model = TwoTower(checkpoint[\\\"num_items\\\"], output_dim=checkpoint[\\\"dim\\\"])\\n     model.load_state_dict(checkpoint[\\\"state_dict\\\"])\\n     model.eval()\\n     features = torch.from_numpy(item_features())\\n+    pop = -np.log1p(np.arange(checkpoint[\\\"num_items\\\"], dtype=np.float32))\\n+    pop = (pop - pop.mean()) / pop.std()\\n+    user_tower = CalibratedUserTower(model.user_tower)\\n+    item_tower = CalibratedItemTower(model.item_tower, torch.from_numpy(pop), pop_blend)\\n     all_ids = torch.arange(1, checkpoint[\\\"num_items\\\"] + 1)\\n     item_vectors = []\\n     for start in range(0, len(all_ids), 2048):\\n         ids = all_ids[start:start + 2048]\\n-        item_vectors.append(model.item_tower(ids, features[start:start + len(ids)]))\\n+        item_vectors.append(item_tower(ids, features[start:start + len(ids)]))\\n@@\\n-        user_vectors.append(model.user_tower(\\n+        user_vectors.append(user_tower(\\n@@\\n-    pop = -np.log1p(np.arange(len(candidate_items), dtype=np.float32))\\n-    pop = (pop - pop.mean()) / pop.std()\\n     result = []\\n@@\\n         stop = min(start + 128, len(uids))\\n         score = (user_vectors[start:stop] @ item_vectors.T).numpy()\\n-        score += pop_blend * pop[None, :]\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:02:33.296Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 125,
      "role": "agent",
      "timestamp": "2026-08-31T19:02:35.915Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:02:35.915Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:02:40.927Z",
          "callId": "call_9vkoTmMHrIo89G2ZWj8Md4r0",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"cp /app/solution/validation_w14_b0.045.parquet /app/solution/validation.parquet\\n/opt/task-venv/bin/python -m py_compile /app/solution/model.py /app/solution/train_ranker.py\\n/opt/task-venv/bin/python /app/solution/train_ranker.py preprocess --stage test --weeks 14 --output /app/solution/test_cache_w14.npz\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:02:51.495Z",
            "content": "Script completed\nWall time 10.6 seconds\nOutput:\n\nTraceback (most recent call last):\n  File \"/app/solution/train_ranker.py\", line 412, in <module>\n    build_cache(args.stage, args.output, args.weeks)\n  File \"/app/solution/train_ranker.py\", line 192, in build_cache\n    data = {name: value[chronology] for name, value in data.items()}\n                  ~~~~~^^^^^^^^^^^^\nIndexError: index 3266 is out of bounds for axis 0 with size 3266\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 126,
      "role": "agent",
      "timestamp": "2026-08-31T19:02:55.770Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:02:55.770Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T19:02:58.590Z",
          "text": "The first refit pass hit a merge-only bug: the validation events were appended to the four event fields, while the unused `uid` array retained its old length. I’ve isolated it to test-stage preprocessing; validation artifacts and the chosen score are unaffected. I’m dropping that redundant per-group field and restarting the refit scan."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:03:02.745Z",
          "callId": "call_voLhSMoo9YE9y4c7UMMmd6Cj",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Update File: /app/solution/train_ranker.py\\n@@\\n     targets = set(pd.read_parquet(DATA / \\\"target_users.parquet\\\").uid.astype(int))\\n     for number, (uid, data) in enumerate(iter_user_groups(listen_paths[0])):\\n         if uid not in targets:\\n             continue\\n+        data.pop(\\\"uid\\\", None)\\n         if test and uid in val_listens:\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:03:02.872Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 127,
      "role": "agent",
      "timestamp": "2026-08-31T19:03:04.735Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:03:04.735Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:03:07.911Z",
          "callId": "call_VzVxEhNmlbtzufB4ABPzXSQJ",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py preprocess --stage test --weeks 14 --output /app/solution/test_cache_w14.npz\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:03:18.931Z",
            "content": "Script running with cell ID 70\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 128,
      "role": "agent",
      "timestamp": "2026-08-31T19:03:20.551Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:03:20.551Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:03:21.322Z",
          "callId": "call_4aNixRnmzMaizvjffkflhopu",
          "name": "wait",
          "input": {
            "cell_id": "70",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:03:38.091Z",
            "content": "Script completed\nWall time 16.8 seconds\nOutput:\n\n\nSESSION_ID=90796",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 129,
      "role": "agent",
      "timestamp": "2026-08-31T19:03:39.698Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:03:39.698Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:03:41.570Z",
          "callId": "call_8kfmpNCQauHbsWCloyt6BUCk",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:90796,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:03:52.588Z",
            "content": "Script running with cell ID 71\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 130,
      "role": "agent",
      "timestamp": "2026-08-31T19:03:54.256Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:03:54.256Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:03:55.031Z",
          "callId": "call_9ah63u76IfUyYsTc1yGgGtsW",
          "name": "wait",
          "input": {
            "cell_id": "71",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:04:11.591Z",
            "content": "Script completed\nWall time 16.6 seconds\nOutput:\n\npreprocessed 1,500 users\n\nSESSION_ID=90796",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 131,
      "role": "agent",
      "timestamp": "2026-08-31T19:04:15.342Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:04:15.342Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:04:17.228Z",
          "callId": "call_cuqOAb4HPcwz8rAjE5L9ftif",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:90796,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:04:28.249Z",
            "content": "Script running with cell ID 72\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 132,
      "role": "agent",
      "timestamp": "2026-08-31T19:04:30.084Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:04:30.084Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:04:30.704Z",
          "callId": "call_pHFylW7da0NYO4h8vhCuaGgR",
          "name": "wait",
          "input": {
            "cell_id": "72",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:04:47.252Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\npreprocessed 3,000 users\n\nSESSION_ID=90796",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 133,
      "role": "agent",
      "timestamp": "2026-08-31T19:04:48.842Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:04:48.842Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:04:50.711Z",
          "callId": "call_xKvK4tDWvbUKytmsyk9bknpn",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:90796,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:05:01.732Z",
            "content": "Script running with cell ID 73\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 134,
      "role": "agent",
      "timestamp": "2026-08-31T19:05:03.647Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:05:03.647Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:05:04.426Z",
          "callId": "call_mhf28jusf3JxIpxlqkGJ9kBU",
          "name": "wait",
          "input": {
            "cell_id": "73",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:05:20.734Z",
            "content": "Script completed\nWall time 16.3 seconds\nOutput:\n\npreprocessed 4,500 users\n\nSESSION_ID=90796",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 135,
      "role": "agent",
      "timestamp": "2026-08-31T19:05:22.943Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:05:22.943Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:05:24.805Z",
          "callId": "call_Bvsmwz76NPbitG5xISx8CgV7",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:90796,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:05:35.824Z",
            "content": "Script running with cell ID 74\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 136,
      "role": "agent",
      "timestamp": "2026-08-31T19:05:37.481Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:05:37.481Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:05:38.335Z",
          "callId": "call_JwETVS8xVPa2POMCq5TPbc54",
          "name": "wait",
          "input": {
            "cell_id": "74",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:05:54.826Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\npreprocessed 6,000 users\n\nSESSION_ID=90796",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 137,
      "role": "agent",
      "timestamp": "2026-08-31T19:05:57.155Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:05:57.155Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:05:59.048Z",
          "callId": "call_6MMbjRytIzknWWRt6OnUuE8t",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:90796,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:06:10.067Z",
            "content": "Script running with cell ID 75\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 138,
      "role": "agent",
      "timestamp": "2026-08-31T19:06:11.832Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:06:11.832Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:06:12.611Z",
          "callId": "call_WtFP4gKCmy1aVaxWa7E7QOWR",
          "name": "wait",
          "input": {
            "cell_id": "75",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:06:29.071Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\n\nSESSION_ID=90796",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 139,
      "role": "agent",
      "timestamp": "2026-08-31T19:06:30.738Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:06:30.738Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:06:32.710Z",
          "callId": "call_IzCIqaayULrgbMTfKkV6nKPB",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:90796,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:06:43.732Z",
            "content": "Script running with cell ID 76\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 140,
      "role": "agent",
      "timestamp": "2026-08-31T19:06:45.434Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:06:45.434Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:06:46.249Z",
          "callId": "call_vOiBkK4qdaqL25Iw2WB6Gu3V",
          "name": "wait",
          "input": {
            "cell_id": "76",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:07:02.735Z",
            "content": "Script completed\nWall time 16.5 seconds\nOutput:\n\npreprocessed 7,500 users\n\nSESSION_ID=90796",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 141,
      "role": "agent",
      "timestamp": "2026-08-31T19:07:04.700Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:07:04.700Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:07:06.587Z",
          "callId": "call_WWcwoPmIg0GowZCKnFqEILTi",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:90796,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:07:17.612Z",
            "content": "Script running with cell ID 77\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 142,
      "role": "agent",
      "timestamp": "2026-08-31T19:07:23.494Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:07:23.494Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:07:24.410Z",
          "callId": "call_VlomEpih0hPFW28qLdYixbZU",
          "name": "wait",
          "input": {
            "cell_id": "77",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:07:32.397Z",
            "content": "Script completed\nWall time 8.0 seconds\nOutput:\n\npreprocessed 9,000 users\n{\"cache\": \"/app/solution/test_cache_w14.npz\", \"contexts\": 126840, \"train_contexts\": 53540, \"targets\": 500389}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 143,
      "role": "agent",
      "timestamp": "2026-08-31T19:07:34.891Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:07:34.891Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:07:38.613Z",
          "callId": "call_3ZQ8RYTC5MFJqyopAZjD9ux7",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py train --cache /app/solution/test_cache_w14.npz --model /app/solution/final_model.pt --epochs 10 --seed 2026 --dim 64\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:07:49.637Z",
            "content": "Script running with cell ID 78\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 144,
      "role": "agent",
      "timestamp": "2026-08-31T19:07:51.381Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:07:51.381Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:07:52.186Z",
          "callId": "call_0HqRDzWV5lZwW5oOLUzrUYhl",
          "name": "wait",
          "input": {
            "cell_id": "78",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:08:08.807Z",
            "content": "Script completed\nWall time 16.6 seconds\nOutput:\n\nepoch 01 loss=0.56720\n\nSESSION_ID=67881",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 145,
      "role": "agent",
      "timestamp": "2026-08-31T19:08:10.455Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:08:10.455Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:08:12.536Z",
          "callId": "call_sTFSkSh0lZbIIAcduGgGdOWN",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:67881,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:08:23.581Z",
            "content": "Script running with cell ID 79\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 146,
      "role": "agent",
      "timestamp": "2026-08-31T19:08:26.326Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:08:26.326Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:08:27.077Z",
          "callId": "call_oRkpgp04SIwy4yKVp8b2zlx0",
          "name": "wait",
          "input": {
            "cell_id": "79",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:08:42.589Z",
            "content": "Script completed\nWall time 15.5 seconds\nOutput:\n\nepoch 02 loss=0.49599\nepoch 03 loss=0.44594\nepoch 04 loss=0.42056\n\nSESSION_ID=67881",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 147,
      "role": "agent",
      "timestamp": "2026-08-31T19:08:44.126Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:08:44.126Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:08:45.982Z",
          "callId": "call_6QX3UZC43idQKQQ4dQeyrMxO",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:67881,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:08:57.018Z",
            "content": "Script running with cell ID 80\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 148,
      "role": "agent",
      "timestamp": "2026-08-31T19:08:59.137Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:08:59.137Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:08:59.906Z",
          "callId": "call_o6rcSBVT4YSvrGrSDDKwRWea",
          "name": "wait",
          "input": {
            "cell_id": "80",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:09:16.024Z",
            "content": "Script completed\nWall time 16.1 seconds\nOutput:\n\nepoch 05 loss=0.40152\nepoch 06 loss=0.38533\n\nSESSION_ID=67881",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 149,
      "role": "agent",
      "timestamp": "2026-08-31T19:09:17.597Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:09:17.597Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:09:19.518Z",
          "callId": "call_OMTgmCucv4Mcifu6uBtxk0Gl",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:67881,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:09:30.573Z",
            "content": "Script running with cell ID 81\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 150,
      "role": "agent",
      "timestamp": "2026-08-31T19:09:33.993Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:09:33.993Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:09:34.786Z",
          "callId": "call_E6atJHngSXjSRsMHMLY3GTfc",
          "name": "wait",
          "input": {
            "cell_id": "81",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:09:49.586Z",
            "content": "Script completed\nWall time 14.8 seconds\nOutput:\n\nepoch 07 loss=0.37165\nepoch 08 loss=0.35662\nepoch 09 loss=0.34501\n\nSESSION_ID=67881",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 151,
      "role": "agent",
      "timestamp": "2026-08-31T19:09:53.302Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:09:53.302Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:09:55.141Z",
          "callId": "call_esY0SCr2GFZFfYYW1TFL5euk",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:67881,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:09:56.230Z",
            "content": "Script completed\nWall time 1.1 seconds\nOutput:\n\nepoch 10 loss=0.32992\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 152,
      "role": "agent",
      "timestamp": "2026-08-31T19:09:59.436Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:09:59.436Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T19:10:02.771Z",
          "text": "The required refit is complete: it uses train plus validation history, including the public window as observed temporal supervision, with 53,540 contexts and 500,389 unseen organic positives. I’m now writing the test ranking through the exact 65-dimensional deployed dot product (64 learned coordinates plus one calibrated popularity coordinate), then independently checking every schema, rank, duplicate, user, and eligibility invariant."
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:10:09.923Z",
          "callId": "call_S21CL730jLc8IMpP5AjNbgwX",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python /app/solution/train_ranker.py rank --cache /app/solution/test_cache_w14.npz --model /app/solution/final_model.pt --stage test --pop-blend 0.045 --output /app/solution/submission.parquet\\n/opt/task-venv/bin/python /app/solution/train_ranker.py rank --cache /app/solution/validation_cache_w14.npz --model /app/solution/validation_model_w14.pt --stage validation --pop-blend 0.045 --output /app/solution/validation.parquet\\n/opt/task-venv/bin/python /task/evaluate_public.py /app/solution/validation.parquet\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:10:20.945Z",
            "content": "Script running with cell ID 83\nWall time 11.0 seconds\nOutput:\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 153,
      "role": "agent",
      "timestamp": "2026-08-31T19:10:24.075Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:10:24.075Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:10:24.922Z",
          "callId": "call_Lu8uDwhukrUmZVjsVGobydp2",
          "name": "wait",
          "input": {
            "cell_id": "83",
            "yield_time_ms": 30000,
            "max_tokens": 14000
          },
          "result": {
            "timestamp": "2026-08-31T19:10:40.104Z",
            "content": "Script completed\nWall time 15.2 seconds\nOutput:\n\n\nSESSION_ID=62874",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 154,
      "role": "agent",
      "timestamp": "2026-08-31T19:10:41.933Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:10:41.933Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:10:43.840Z",
          "callId": "call_yj1962PEmXjMuVs4HWOmMLvt",
          "name": "exec",
          "input": {
            "code": "const r = await tools.write_stdin({session_id:62874,chars:\"\",yield_time_ms:30000,max_output_tokens:14000}); text(r.output); if(r.session_id) text(`SESSION_ID=${r.session_id}`)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:10:43.917Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{\n  \"model\": \"/app/solution/validation.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.019178,\n    \"quality_users\": 4263\n  }\n}\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 155,
      "role": "agent",
      "timestamp": "2026-08-31T19:11:02.645Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:11:02.645Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:11:26.011Z",
          "callId": "call_UgrhyMsSMhRcGaUYl7zHfGWu",
          "name": "exec",
          "input": {
            "code": "const patch = \"*** Begin Patch\\n*** Add File: /app/solution/README.md\\n+# CPU PyTorch two-tower ranker\\n+\\n+## Model\\n+\\n+`model.py` defines separate trainable `UserTower` and `ItemTower` PyTorch\\n+networks. The user tower contains no user-ID embedding: it pools up to 256\\n+catalog tracks from positive listen/like history into long- and short-recency\\n+views, separately pools active dislikes, appends four history-size features,\\n+and applies a 192/128-unit MLP. The item tower combines a trainable track\\n+embedding with four catalog popularity features and applies a 160/128-unit\\n+MLP. Both return 64-dimensional normalized vectors.\\n+\\n+Deployment wraps these towers with one calibrated popularity coordinate. The\\n+resulting independently computable user and item vectors are both 65-D and the\\n+complete relevance score is exactly their inner product. Item vectors can be\\n+materialized offline in one pass; request-time work is one history-based user\\n+tower evaluation followed by maximum-inner-product retrieval.\\n+\\n+## Training\\n+\\n+`train_ranker.py` streams uid/time-sorted event Parquets one user at a time and\\n+never constructs or factorizes a global user-item matrix. Sixteen-byte catalog\\n+indices are not used as user IDs. Supervision comes from fourteen rolling,\\n+cutoff-correct temporal backtests: a context uses only earlier interactions and\\n+targets previously unseen catalog tracks with an organic 80% listen (gain 1)\\n+or organic like (gain 7). The pairwise softplus/BPR objective uses 32 sampled\\n+negatives per positive, half popularity-shaped and half uniform. Validation\\n+selection used train events only; the final model was refit from scratch with\\n+train plus validation events as history/supervision.\\n+\\n+## Validation\\n+\\n+Public graded NDCG@10: **0.019178** over 4,263 scored users. The popularity-only\\n+fallback scored 0.010710. The retained validation ranking is\\n+`validation.parquet`.\\n+\\n+## Final submission command\\n+\\n+Run from `/app/solution` with the task's read-only virtual environment:\\n+\\n+```sh\\n+/opt/task-venv/bin/python train_ranker.py preprocess --stage test --weeks 14 --output test_cache_w14.npz && \\\\\\n+/opt/task-venv/bin/python train_ranker.py train --cache test_cache_w14.npz --model final_model.pt --epochs 10 --seed 2026 --dim 64 && \\\\\\n+/opt/task-venv/bin/python train_ranker.py rank --cache test_cache_w14.npz --model final_model.pt --stage test --pop-blend 0.045 --output submission.parquet\\n+```\\n+\\n+The checked-in `submission.parquet` was produced by that command.\\n*** End Patch\";\ntext(await tools.apply_patch(patch));\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:11:26.146Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 156,
      "role": "agent",
      "timestamp": "2026-08-31T19:11:31.645Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:11:31.645Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:11:45.316Z",
          "callId": "call_e7aPwgt8q2cUxM66TZgY9IRV",
          "name": "exec",
          "input": {
            "code": "const r = await tools.exec_command({cmd:\"/opt/task-venv/bin/python - <<'PY'\\nimport sys\\nfrom pathlib import Path\\nsys.path.insert(0,'/task')\\nimport pandas as pd\\nfrom ranking_evaluation import CandidateSet, validate_ranking\\nD=Path('/task/data'); S=Path('/app/solution/submission.parquet')\\ntargets=set(pd.read_parquet(D/'target_users.parquet').uid.astype(int))\\nframe=validate_ranking(pd.read_parquet(S),targets)\\ncandidates=CandidateSet(D/'test_eligible_candidates.npz')\\nbad=[(int(u),int(i)) for u,i in frame[['uid','item_id']].itertuples(index=False,name=None) if not candidates.is_eligible(int(u),int(i))]\\nprint({'rows':len(frame),'users':frame.uid.nunique(),'items_per_user_min':int(frame.groupby('uid').size().min()),'items_per_user_max':int(frame.groupby('uid').size().max()),'rank_min':int(frame['rank'].min()),'rank_max':int(frame['rank'].max()),'duplicate_pairs':int(frame.duplicated(['uid','item_id']).sum()),'ineligible':len(bad),'dtypes':{k:str(v) for k,v in frame.dtypes.items()}})\\nPY\\nsha256sum /app/solution/submission.parquet /app/solution/validation.parquet /app/solution/final_model.pt\\nls -lh /app/solution | sed -n '1,120p'\\n/opt/task-venv/bin/python -m py_compile /app/solution/*.py\",\"workdir\":\"/app\",\"yield_time_ms\":30000,\"max_output_tokens\":12000}); text(r.output)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:11:48.452Z",
            "content": "Script completed\nWall time 3.1 seconds\nOutput:\n\n{'rows': 845600, 'users': 8456, 'items_per_user_min': 100, 'items_per_user_max': 100, 'rank_min': 1, 'rank_max': 100, 'duplicate_pairs': 0, 'ineligible': 0, 'dtypes': {'uid': 'int64', 'item_id': 'int64', 'rank': 'int64'}}\n99eca83d4bdfe351db6f8a34e912f223d239624d96c010698b8859ab60dc6be9  /app/solution/submission.parquet\n9e2e79936c0e5080e3ab390d0d873eb52a6c157eb1974372a2e0dbeffcc979f2  /app/solution/validation.parquet\n4c235367aed81ae34f579f31d2f4f81bdfb20377f892439a96655ca7dc963bf9  /app/solution/final_model.pt\ntotal 588M\n-rw-r--r-- 1 agent agent 2.4K Aug 31 19:11 README.md\ndrwxr-xr-x 2 agent agent 4.0K Aug 31 19:02 __pycache__\n-rw-r--r-- 1 agent agent 1.2K Aug 31 18:27 build_popularity.py\n-rw-r--r-- 1 agent agent  23M Aug 31 19:09 final_model.pt\n-rw-r--r-- 1 agent agent 3.7K Aug 31 19:02 model.py\n-rw-r--r-- 1 agent agent 1.4M Aug 31 19:10 submission.parquet\n-rw-r--r-- 1 agent agent 194M Aug 31 19:07 test_cache_w14.npz\n-rw-r--r-- 1 agent agent  20K Aug 31 19:03 train_ranker.py\n-rw-r--r-- 1 agent agent 1.4M Aug 31 19:10 validation.parquet\n-rw-r--r-- 1 agent agent 1.5M Aug 31 18:48 validation_b0.02.parquet\n-rw-r--r-- 1 agent agent 1.4M Aug 31 18:49 validation_b0.05.parquet\n-rw-r--r-- 1 agent agent 1.4M Aug 31 18:49 validation_b0.08.parquet\n-rw-r--r-- 1 agent agent 1.3M Aug 31 18:49 validation_b0.12.parquet\n-rw-r--r-- 1 agent agent 1.2M Aug 31 18:49 validation_b0.18.parquet\n-rw-r--r-- 1 agent agent 1.5M Aug 31 18:48 validation_b0.parquet\n-rw-r--r-- 1 agent agent  98M Aug 31 18:42 validation_cache.npz\n-rw-r--r-- 1 agent agent 190M Aug 31 18:54 validation_cache_w14.npz\n-rw-r--r-- 1 agent agent  23M Aug 31 18:47 validation_model.pt\n-rw-r--r-- 1 agent agent  23M Aug 31 18:57 validation_model_w14.pt\n-rw-r--r-- 1 agent agent  23M Aug 31 19:01 validation_model_w14_s314.pt\n-rw-r--r-- 1 agent agent 1.4M Aug 31 18:57 validation_w14_b0.03.parquet\n-rw-r--r-- 1 agent agent 1.4M Aug 31 18:57 validation_w14_b0.045.parquet\n-rw-r--r-- 1 agent agent 1.4M Aug 31 18:58 validation_w14_b0.06.parquet\n-rw-r--r-- 1 agent agent 1.4M Aug 31 18:58 validation_w14_b0.075.parquet\n-rw-r--r-- 1 agent agent 1.4M Aug 31 19:01 validation_w14_s314.parquet\n",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 157,
      "role": "agent",
      "timestamp": "2026-08-31T19:11:52.346Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:11:52.346Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-08-31T19:11:57.285Z",
          "callId": "call_td0EzeXxZkDo83DsUouKLmm6",
          "name": "exec",
          "input": {
            "code": "const p = await tools.update_plan({explanation:\"Implemented, tuned, refit, ranked, and independently validated the final artifact.\",plan:[\n  {step:\"Inspect data schemas, sizes, cutoffs, eligibility, and evaluator\",status:\"completed\"},\n  {step:\"Implement scalable PyTorch two-tower training and ranking pipeline\",status:\"completed\"},\n  {step:\"Train validation variants and evaluate public NDCG@10\",status:\"completed\"},\n  {step:\"Refit selected model on train+validation and create valid test submission\",status:\"completed\"},\n  {step:\"Verify artifacts and document reproducible commands\",status:\"completed\"}\n]}); text(p)\n"
          },
          "result": {
            "timestamp": "2026-08-31T19:11:57.413Z",
            "content": "Script completed\nWall time 0.0 seconds\nOutput:\n\n{}",
            "isError": null
          }
        }
      ]
    },
    {
      "id": 158,
      "role": "agent",
      "timestamp": "2026-08-31T19:12:01.775Z",
      "blocks": [
        {
          "kind": "reasoning",
          "representation": "summary",
          "timestamp": "2026-08-31T19:12:01.775Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-08-31T19:12:08.923Z",
          "text": "Implemented and verified the CPU PyTorch two-tower ranker.\n\n- Final submission: [submission.parquet](/app/solution/submission.parquet)\n- Training/ranking pipeline: [train_ranker.py](/app/solution/train_ranker.py)\n- Tower definitions: [model.py](/app/solution/model.py)\n- Documentation: [README.md](/app/solution/README.md)\n- Public validation ranking: [validation.parquet](/app/solution/validation.parquet)\n\nPublic NDCG@10: **0.019178** over 4,263 users.\n\nFinal submission validation:\n\n- 845,600 rows\n- 8,456 users\n- Exactly 100 unique items and ranks 1–100 per user\n- Zero ineligible items\n- Final model refitted on train + validation history\n- Exact 65-dimensional user/item dot-product scoring\n- No user-ID embeddings or global user-item matrix construction"
        }
      ]
    }
  ]
}
