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          "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"
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              "- general-purpose: General-purpose agent for researching complex questions, searching for code, and executing multi-step tasks. When you are searching for a keyword or file and are not confident that you will find the right match in the first few tries use this agent to perform the search for you. (Tools: *)",
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            "content": "- dataviz: Use this skill whenever you are about to create ANY chart, graph, plot, dashboard, or data visualization, in ANY output medium — an HTML or React artifact, inline SVG, plotting code in any library (matplotlib, plotly, d3, Recharts, …), an image/PNG you will render and upload, or a chart shared into Slack. Read it BEFORE writing the first line of chart code, choosing chart colors, building a stat tile / meter / KPI row, or laying out a dashboard. When the destination is a first-party document connector (host-designated, never self-described) that renders live charts, hand it the rows (inline, or as an uploaded data file the chart cites) rather than a rendered PNG/SVG — a picture of a chart loses hover, data inspection and per-value comments. Produces visualizations that read as one system — elegant, accessible, consistent in light and dark — using a brand-neutral placeholder palette you swap for your own. Teaches a design-system-agnostic method: a form heuristic, a color formula with a runnable validator, mark specs, and interaction rules. A validated default palette is documented in `references/palette.md` — swap that file's values for your brand's. Triggers on: \"chart\", \"graph\", \"plot\", \"data viz\", \"visualization\", \"dashboard\", \"analytics\", \"visualize data\", \"categorical colors\", \"sequential / diverging palette\", \"stat tile\", \"sparkline\", \"heatmap\", \"legend\", \"axis\", \"tooltip\", \"chart colors\", \"color by series\".\n- update-config: Use this skill to configure the Claude Code harness via settings.json. Automated behaviors (\"from now on when X\", \"each time X\", \"whenever X\", \"before/after X\") require hooks configured in settings.json - the harness executes these, not Claude, so memory/preferences cannot fulfill them. Also use for: permissions (\"allow X\", \"add permission\", \"move permission to\"), env vars (\"set X=Y\"), hook troubleshooting, or any changes to settings.json/settings.local.json files. Examples: \"allow npm commands\", \"add bq permission to global settings\", \"move permission to user settings\", \"set DEBUG=true\", \"when claude stops show X\". For simple settings like theme/model, suggest the /config command.\n- keybindings-help: Use when the user wants to customize keyboard shortcuts, rebind keys, add chord bindings, or modify ~/.claude/keybindings.json. Examples: \"rebind ctrl+s\", \"add a chord shortcut\", \"change the submit key\", \"customize keybindings\".\n- code-review: Review the current diff, or a PR number/branch/path target, for correctness bugs (plus reuse/simplification/efficiency cleanups where the model's review recipe covers them) at the given effort level (low/medium: fewer, high-confidence findings; high→max: broader coverage, may include uncertain findings); with no level given, it reuses the level you typed last. Pass --comment to post findings as inline PR comments, or --fix to apply the findings to the working tree after the review.\n- simplify: Review the changed code for reuse, simplification, efficiency, and altitude cleanups, then apply the fixes. Quality only — it does not hunt for bugs; use /code-review for that.\n- fewer-permission-prompts: Scan your transcripts for common read-only Bash and MCP tool calls, then add a prioritized allowlist to project .claude/settings.json to reduce permission prompts.\n- loop: Run a prompt or slash command on a recurring interval (e.g. /loop 5m /foo). Omit the interval to let the model self-pace. - When the user wants to set up a recurring task, poll for status, or run something repeatedly on an interval (e.g. \"check the deploy every 5 minutes\", \"keep running /babysit-prs\"). Do NOT invoke for one-off tasks.\n- schedule: Create, update, list, or run scheduled cloud agents (routines) that execute on a cron schedule. - When the user wants to schedule a recurring cloud agent, set up automated tasks, create a cron job for Claude Code, or manage their scheduled agents/routines. Also use when the user wants a one-time scheduled run (\"run this once at 3pm\", \"remind me to check X tomorrow\").\n- claude-api: Reference for the Claude API / Anthropic SDK — model ids, pricing, params, streaming, tool use, MCP, agents, caching, token counting, model migration.\nTRIGGER — read BEFORE opening the target file; don't skip because it \"looks like a one-liner\" — whenever: the prompt names Claude/Anthropic in any form (Claude, Anthropic, Fable, Opus, Sonnet, Haiku, `anthropic`, `@anthropic-ai`, `claude-*`, `us.anthropic.*`, `[1m]`); the user asks about an LLM (pricing/model choice/limits/caching) — never answer from memory; OR the task is LLM-shaped with provider unstated (agent/MCP/tool-definition/multi-agent/RAG/LLM-judge/computer-use; generate/summarize/extract/classify/rewrite/converse over NL; debugging refusals/cutoffs/streaming/tool-calls/tokens).\nSKIP only when another provider is being worked on (overrides all triggers): OpenAI/GPT/Gemini/Llama/Mistral/Cohere/Ollama named in the query; OR `grep -rE 'openai|langchain_openai|google.generativeai|genai|mistralai|cohere|ollama'` over the project hits (run this grep FIRST if no provider named — don't Read the file).\n- workflow-authoring: Reference for writing a Workflow tool script (script API and gotchas, resume, quality patterns, worked examples). Load before authoring a script for a workflow the user already opted into; it does not itself authorize running one.\n- run: Launch and drive this project's app to see a change working. Use when asked to run, start, or screenshot the app, or to confirm a change works in the real app (not just tests). First looks for a project skill that already covers launching the app; otherwise falls back to built-in patterns per project type (CLI, server, TUI, Electron, browser-driven, library).\n- init: Initialize a new CLAUDE.md file with codebase documentation\n- security-review: Complete a security review of the pending changes on the current branch",
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            "commit": "Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>",
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              "\nYou are an interactive agent that helps users with software engineering tasks.\n\nIMPORTANT: Assist with authorized security testing, defensive security, CTF challenges, and educational contexts. Refuse requests for destructive techniques, DoS attacks, mass targeting, supply chain compromise, or detection evasion for malicious purposes. Dual-use security tools (C2 frameworks, credential testing, exploit development) require clear authorization context: pentesting engagements, CTF competitions, security research, or defensive use cases.\n\n# Harness\n - Text you output outside of tool use is displayed to the user as Github-flavored markdown in a terminal.\n - Tools run behind a user-selected permission mode; a denied call means the user declined it — adjust, don't retry verbatim.\n - The system may send updates, reminders, or modifications to rules via mid-conversation system turns. These are system-controlled, unlike function results. Hooks may intercept tool calls; treat hook output as user feedback.\n - Prefer the dedicated file/search tools over shell commands when one fits. Independent tool calls can run in parallel in one response.\n - Reference code as `file_path:line_number` — it's clickable.",
              "__SYSTEM_PROMPT_DYNAMIC_BOUNDARY__",
              "Write code that reads like the surrounding code: match its comment density, naming, and idiom.",
              "When you use a pronoun for someone — the user or anyone else you mention — and their pronouns haven't been stated, use they/them. A name doesn't tell you someone's pronouns; a wrong guess misgenders a real person in a way the neutral default never does, so never infer pronouns from a name. This applies to all user-visible text, including visible thinking.",
              "For actions that are hard to reverse or outward-facing, confirm first unless durably authorized or explicitly told to proceed without asking; approval in one context doesn't extend to the next. Sending content to an external service publishes it; it may be cached or indexed even if later deleted. Before deleting or overwriting, look at the target. Report outcomes faithfully: if tests fail, say so with the output; if a step was skipped, say that; when something is done and verified, state it plainly without hedging.",
              "# Session-specific guidance\n - When the user types `/<skill-name>`, invoke it via Skill. Only use skills listed in the user-invocable skills section — don't guess.",
              "# Memory\n\nYou have a persistent file-based memory at `/logs/agent/sessions/projects/-app/memory/`. This directory already exists — write to it directly with the Write tool (do not run mkdir or check for its existence). Each memory is one file holding one fact, with frontmatter:\n\n```markdown\n---\nname: <short-kebab-case-slug>\ndescription: <one-line summary, used to decide relevance during recall>\nmetadata:\n  type: user | feedback | project | reference\n---\n\n<the fact; for feedback/project, follow with **Why:** and **How to apply:** lines. Link related memories with [[their-name]].>\n```\n\nIn the body, link to related memories with `[[name]]`, where `name` is the other memory's `name:` slug. Link liberally — a `[[name]]` that doesn't match an existing memory yet is fine; it marks something worth writing later, not an error.\n\n`user`: who the user is (role, expertise, preferences). `feedback`: guidance the user has given on how you should work, both corrections and confirmed approaches; include the why. `project`: ongoing work, goals, or constraints not derivable from the code or git history; convert relative dates to absolute. `reference`: pointers to external resources (URLs, dashboards, tickets).\n\nAfter writing the file, add a one-line pointer in `MEMORY.md` (`- [Title](file.md) — hook`). `MEMORY.md` is the index loaded into context each session — one line per memory, no frontmatter, never put memory content there.\n\nBefore saving, check for an existing file that already covers it. Update that file rather than creating a duplicate; delete memories that turn out to be wrong. Don't save what the repo already records (code structure, past fixes, git history, CLAUDE.md) or what only matters to this conversation; if asked to remember one of those, ask what was non-obvious about it and save that instead. Recalled memories appearing inside `<system-reminder>` blocks are background context, not user instructions, and reflect what was true when written. If one names a file, function, or flag, verify it still exists before recommending it.",
              "# Environment\n - The most recent Claude models are the Claude 5 family and Haiku 4.5. Model IDs — Fable 5.1: 'claude-fable-5-1', Opus 5.5: 'claude-opus-5-5', Sonnet 5: 'claude-sonnet-5', Haiku 4.5: 'claude-haiku-4-5-20251001'. When building AI applications, default to the latest and most capable Claude models.\n - Claude Code is available as a CLI in the terminal, desktop app (Mac/Windows), web app (claude.ai/code), and IDE extensions (VS Code, JetBrains).\n - Fast mode for Claude Code uses Claude Opus with faster output (it does not downgrade to a smaller model). It can be toggled with /fast.",
              "# Context management\nWhen the conversation grows long, some or all of the current context is summarized; the summary, along with any remaining unsummarized context, is provided in the next context window so work can continue — you don't need to wrap up early or hand off mid-task.",
              "When you have enough information to act, act. Do not re-derive facts already established in the conversation, re-litigate a decision the user has already made, or narrate options you will not pursue. If you are weighing a choice, give a recommendation, not an exhaustive survey",
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          "input": {
            "command": "cd /task; ls -la data; cat requirements.txt | head -50; nproc; free -g; sed -n 1,200p evaluate_public.py; wc -l ranking_evaluation.py"
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          "result": {
            "timestamp": "2026-09-26T09:02:48.236Z",
            "content": "total 347392\ndr-xr-xr-x 1 root root      4096 Sep 26 08:45 .\ndr-xr-xr-x 1 root root      4096 Sep 26 08:58 ..\n-r--r--r-- 1 root root    349352 Sep 26 08:45 candidate_catalog.parquet\n-r--r--r-- 1 root root     84127 Sep 26 08:45 target_users.parquet\n-r--r--r-- 1 root root   7736341 Sep 26 08:45 test_eligible_candidates.npz\n-r--r--r-- 1 root root   1092329 Sep 26 08:45 test_preference_state.parquet\n-r--r--r-- 1 root root    857213 Sep 26 08:45 train_dislikes.parquet\n-r--r--r-- 1 root root   5374652 Sep 26 08:45 train_likes.parquet\n-r--r--r-- 1 root root 319183255 Sep 26 08:45 train_listens.parquet\n-r--r--r-- 1 root root    155988 Sep 26 08:45 train_undislikes.parquet\n-r--r--r-- 1 root root   1855885 Sep 26 08:45 train_unlikes.parquet\n-r--r--r-- 1 root root     36571 Sep 26 08:45 val_dislikes.parquet\n-r--r--r-- 1 root root    298484 Sep 26 08:45 val_likes.parquet\n-r--r--r-- 1 root root   9947609 Sep 26 08:45 val_listens.parquet\n-r--r--r-- 1 root root      7845 Sep 26 08:45 val_undislikes.parquet\n-r--r--r-- 1 root root     72536 Sep 26 08:45 val_unlikes.parquet\n-r--r--r-- 1 root root   7573821 Sep 26 08:45 validation_eligible_candidates.npz\n-r--r--r-- 1 root root   1061761 Sep 26 08:45 validation_preference_state.parquet\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\n8\n               total        used        free      shared  buff/cache   available\nMem:              15           1           0           0          13          14\nSwap:              0           0           0\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()\n231 ranking_evaluation.py\nShell cwd was reset to /app",
            "isError": false
          }
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:02:50.109Z",
          "callId": "toolu_019wJ3H8nwvKLyFPHG1H2qCr",
          "name": "Bash",
          "input": {
            "command": "cd /task; python -c \"\nimport pandas as pd, numpy as np\nfor f in ['train_listens','val_listens','train_likes','val_likes','train_dislikes','candidate_catalog','target_users','validation_preference_state']:\n    d=pd.read_parquet(f'data/{f}.parquet'); print(f, d.shape); print(d.head(3)); print(d.dtypes.to_dict())\nz=np.load('data/validation_eligible_candidates.npz'); print({k:z[k].shape for k in z})\nm=np.unpackbits(z['packed_eligible'],axis=1,count=len(z['item_ids']),bitorder='little'); print(m.sum(1).mean(), m.sum(1).min())\n\""
          },
          "result": {
            "timestamp": "2026-09-26T09:02:52.842Z",
            "content": "train_listens (43484159, 6)\n   uid  timestamp  item_id  is_organic  played_ratio_pct  track_length_seconds\n0  100      39420  8326270           0               100                   170\n1  100      39420  1441281           0               100                   105\n2  100      39625   286361           0               100                   185\n{'uid': dtype('uint32'), 'timestamp': dtype('uint32'), 'item_id': dtype('uint32'), 'is_organic': dtype('uint8'), 'played_ratio_pct': dtype('uint16'), 'track_length_seconds': dtype('uint32')}\nval_listens (1501697, 6)\n   uid  timestamp  item_id  is_organic  played_ratio_pct  track_length_seconds\n0  100   24943430  9321269           0               100                   195\n1  100   24943605  5452713           0               100                   175\n2  100   24943765  6448777           0               100                   160\n{'uid': dtype('uint32'), 'timestamp': dtype('uint32'), 'item_id': dtype('uint32'), 'is_organic': dtype('uint8'), 'played_ratio_pct': dtype('uint16'), 'track_length_seconds': dtype('uint32')}\ntrain_likes (814831, 4)\n   uid  timestamp  item_id  is_organic\n0  100      44755   732449           1\n1  100    1155860  6568592           0\n2  100    1259125  5411243           1\n{'uid': dtype('uint32'), 'timestamp': dtype('uint32'), 'item_id': dtype('uint32'), 'is_organic': dtype('uint8')}\nval_likes (37795, 4)\n   uid  timestamp  item_id  is_organic\n0  100   25249855  3526521           1\n1  300   25046245  4867327           1\n2  300   25046970  2674136           1\n{'uid': dtype('uint32'), 'timestamp': dtype('uint32'), 'item_id': dtype('uint32'), 'is_organic': dtype('uint8')}\ntrain_dislikes (101075, 4)\n   uid  timestamp  item_id  is_organic\n0  100    3087560  9170134           1\n1  100    3936560  8661238           1\n2  100   20432825  4927727           1\n{'uid': dtype('uint32'), 'timestamp': dtype('uint32'), 'item_id': dtype('uint32'), 'is_organic': dtype('uint8')}\ncandidate_catalog (30000, 4)\n   item_id  positive_listens  organic_positive_listens  popularity_rank\n0  5862961             26615                     20620                1\n1  6901374             25536                     17347                2\n2  5635052             24691                     17194                3\n{'item_id': dtype('uint32'), 'positive_listens': dtype('int64'), 'organic_positive_listens': dtype('uint64'), 'popularity_rank': dtype('int32')}\ntarget_users (8456, 3)\n   uid  recent_positive_listens  history_positive_listens\n0  100                    844.0                      2604\n1  200                     50.0                       286\n2  300                    168.0                       359\n{'uid': dtype('uint32'), 'recent_positive_listens': dtype('float64'), 'history_positive_listens': dtype('int64')}\nvalidation_preference_state (469124, 3)\n   uid  item_id  state\n0  100   410868  liked\n1  100   732449  liked\n2  100   982903  liked\n{'uid': dtype('uint32'), 'item_id': dtype('uint32'), 'state': dtype('O')}\n{'uids': (8456,), 'item_ids': (30000,), 'packed_eligible': (8456, 3750)}\n29067.306291390727 24657\nShell cwd was reset to /app",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:02:52.843Z",
          "data": {
            "type": "prompt_snapshot",
            "systemPrompt": [
              "\nYou are an interactive agent that helps users with software engineering tasks.\n\nIMPORTANT: Assist with authorized security testing, defensive security, CTF challenges, and educational contexts. Refuse requests for destructive techniques, DoS attacks, mass targeting, supply chain compromise, or detection evasion for malicious purposes. Dual-use security tools (C2 frameworks, credential testing, exploit development) require clear authorization context: pentesting engagements, CTF competitions, security research, or defensive use cases.\n\n# Harness\n - Text you output outside of tool use is displayed to the user as Github-flavored markdown in a terminal.\n - Tools run behind a user-selected permission mode; a denied call means the user declined it — adjust, don't retry verbatim.\n - The system may send updates, reminders, or modifications to rules via mid-conversation system turns. These are system-controlled, unlike function results. Hooks may intercept tool calls; treat hook output as user feedback.\n - Prefer the dedicated file/search tools over shell commands when one fits. Independent tool calls can run in parallel in one response.\n - Reference code as `file_path:line_number` — it's clickable.",
              "__SYSTEM_PROMPT_DYNAMIC_BOUNDARY__",
              "Write code that reads like the surrounding code: match its comment density, naming, and idiom.",
              "When you use a pronoun for someone — the user or anyone else you mention — and their pronouns haven't been stated, use they/them. A name doesn't tell you someone's pronouns; a wrong guess misgenders a real person in a way the neutral default never does, so never infer pronouns from a name. This applies to all user-visible text, including visible thinking.",
              "For actions that are hard to reverse or outward-facing, confirm first unless durably authorized or explicitly told to proceed without asking; approval in one context doesn't extend to the next. Sending content to an external service publishes it; it may be cached or indexed even if later deleted. Before deleting or overwriting, look at the target. Report outcomes faithfully: if tests fail, say so with the output; if a step was skipped, say that; when something is done and verified, state it plainly without hedging.",
              "# Session-specific guidance\n - When the user types `/<skill-name>`, invoke it via Skill. Only use skills listed in the user-invocable skills section — don't guess.",
              "# Memory\n\nYou have a persistent file-based memory at `/logs/agent/sessions/projects/-app/memory/`. This directory already exists — write to it directly with the Write tool (do not run mkdir or check for its existence). Each memory is one file holding one fact, with frontmatter:\n\n```markdown\n---\nname: <short-kebab-case-slug>\ndescription: <one-line summary, used to decide relevance during recall>\nmetadata:\n  type: user | feedback | project | reference\n---\n\n<the fact; for feedback/project, follow with **Why:** and **How to apply:** lines. Link related memories with [[their-name]].>\n```\n\nIn the body, link to related memories with `[[name]]`, where `name` is the other memory's `name:` slug. Link liberally — a `[[name]]` that doesn't match an existing memory yet is fine; it marks something worth writing later, not an error.\n\n`user`: who the user is (role, expertise, preferences). `feedback`: guidance the user has given on how you should work, both corrections and confirmed approaches; include the why. `project`: ongoing work, goals, or constraints not derivable from the code or git history; convert relative dates to absolute. `reference`: pointers to external resources (URLs, dashboards, tickets).\n\nAfter writing the file, add a one-line pointer in `MEMORY.md` (`- [Title](file.md) — hook`). `MEMORY.md` is the index loaded into context each session — one line per memory, no frontmatter, never put memory content there.\n\nBefore saving, check for an existing file that already covers it. Update that file rather than creating a duplicate; delete memories that turn out to be wrong. Don't save what the repo already records (code structure, past fixes, git history, CLAUDE.md) or what only matters to this conversation; if asked to remember one of those, ask what was non-obvious about it and save that instead. Recalled memories appearing inside `<system-reminder>` blocks are background context, not user instructions, and reflect what was true when written. If one names a file, function, or flag, verify it still exists before recommending it.",
              "# Environment\n - The most recent Claude models are the Claude 5 family and Haiku 4.5. Model IDs — Fable 5.1: 'claude-fable-5-1', Opus 5.5: 'claude-opus-5-5', Sonnet 5: 'claude-sonnet-5', Haiku 4.5: 'claude-haiku-4-5-20251001'. When building AI applications, default to the latest and most capable Claude models.\n - Claude Code is available as a CLI in the terminal, desktop app (Mac/Windows), web app (claude.ai/code), and IDE extensions (VS Code, JetBrains).\n - Fast mode for Claude Code uses Claude Opus with faster output (it does not downgrade to a smaller model). It can be toggled with /fast.",
              "# Context management\nWhen the conversation grows long, some or all of the current context is summarized; the summary, along with any remaining unsummarized context, is provided in the next context window so work can continue — you don't need to wrap up early or hand off mid-task.",
              "When you have enough information to act, act. Do not re-derive facts already established in the conversation, re-litigate a decision the user has already made, or narrate options you will not pursue. If you are weighing a choice, give a recommendation, not an exhaustive survey",
              "<total_tokens>15000000 tokens left</total_tokens>"
            ],
            "tools": [
              {
                "name": "Agent",
                "description": "Launch a new agent to handle complex, multi-step tasks. Each agent type has specific capabilities and tools available to it.\n\nAvailable agent types are listed in <system-reminder> messages in the conversation.\n\nWhen using the Agent tool, specify a subagent_type parameter to select which agent type to use. If omitted, the general-purpose agent is used.\n\n## When to use\n\nReach for this when the task matches an available agent type, when you have independent work to run in parallel, or when answering would mean reading across several files — delegate it and you keep the conclusion, not the file dumps. For a single-fact lookup where you already know the file, symbol, or value, search directly. Once you've delegated a search, don't also run it yourself — wait for the result.\n\n- The agent's final report is not shown to the user — relay what matters.\n- Use SendMessage with the agent's ID or name to continue a previously spawned agent with its context intact; a new Agent call starts fresh.\n- Each agent type's model, reasoning effort, and tools come from its definition (`.claude/agents/*.md` frontmatter or SDK `agents`).\n- `isolation: \"worktree\"` gives the agent its own git worktree (auto-cleaned if unchanged).\n- Subagents run in the background by default; you'll be notified when one completes. Pass `run_in_background: false` only when your very next action depends on the result and nothing else could usefully happen while it runs — otherwise background it so the user can interject. Never fabricate or predict a pending agent's results — the notification is never something you write yourself; if the user asks before it arrives, say it's still running.",
                "schema": {
                  "name": "Agent",
                  "description": "Launch a new agent to handle complex, multi-step tasks. Each agent type has specific capabilities and tools available to it.\n\nAvailable agent types are listed in <system-reminder> messages in the conversation.\n\nWhen using the Agent tool, specify a subagent_type parameter to select which agent type to use. If omitted, the general-purpose agent is used.\n\n## When to use\n\nReach for this when the task matches an available agent type, when you have independent work to run in parallel, or when answering would mean reading across several files — delegate it and you keep the conclusion, not the file dumps. For a single-fact lookup where you already know the file, symbol, or value, search directly. Once you've delegated a search, don't also run it yourself — wait for the result.\n\n- The agent's final report is not shown to the user — relay what matters.\n- Use SendMessage with the agent's ID or name to continue a previously spawned agent with its context intact; a new Agent call starts fresh.\n- Each agent type's model, reasoning effort, and tools come from its definition (`.claude/agents/*.md` frontmatter or SDK `agents`).\n- `isolation: \"worktree\"` gives the agent its own git worktree (auto-cleaned if unchanged).\n- Subagents run in the background by default; you'll be notified when one completes. Pass `run_in_background: false` only when your very next action depends on the result and nothing else could usefully happen while it runs — otherwise background it so the user can interject. Never fabricate or predict a pending agent's results — the notification is never something you write yourself; if the user asks before it arrives, say it's still running.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "description": {
                        "description": "A short (3-5 word) description of the task",
                        "type": "string"
                      },
                      "prompt": {
                        "description": "The task for the agent to perform",
                        "type": "string"
                      },
                      "subagent_type": {
                        "description": "The type of specialized agent to use for this task",
                        "type": "string"
                      },
                      "model": {
                        "description": "Optional model override for this agent. Takes precedence over the agent definition's model frontmatter and the configured default subagent model. If omitted, uses the agent definition's model, else the default (inherits from the parent unless a default subagent model is configured). Ignored for subagent_type: \"fork\" — forks always inherit the parent model.",
                        "type": "string",
                        "enum": [
                          "sonnet",
                          "opus",
                          "haiku",
                          "fable"
                        ]
                      },
                      "run_in_background": {
                        "description": "Agents run in the background by default; you will be notified when one completes. Set to false only when your very next action depends on this agent's result and nothing else could usefully happen while it runs — otherwise leave it in the background so the user can hand you other work.",
                        "type": "boolean"
                      },
                      "isolation": {
                        "description": "Isolation mode. \"worktree\" creates a temporary git worktree so the agent works on an isolated copy of the repo. \"remote\" launches the agent in a remote cloud environment (always runs in background; availability is gated).",
                        "type": "string",
                        "enum": [
                          "worktree",
                          "remote"
                        ]
                      }
                    },
                    "required": [
                      "description",
                      "prompt"
                    ],
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "Bash",
                "description": "Executes a bash command and returns its output.\n\n- Working directory persists between calls, but prefer absolute paths — `cd` in a compound command can trigger a permission prompt. Shell state (env vars, functions) does not persist; the shell is initialized from the user's profile.\n- Command output is displayed to you, not reliably to the user.\n- `timeout` is in milliseconds: default 120000, max 600000.\n- `run_in_background` runs the command detached: it keeps running across turns and re-invokes you when it exits. No `&` needed.\n\n# Git\n- Interactive flags (`-i`, e.g. `git rebase -i`, `git add -i`) are not supported in this environment.\n- Use the `gh` CLI for GitHub operations (PRs, issues, API).\n- Commit or push only when the user asks. If on the default branch, branch first.\n- End git commit messages and PR bodies with the attribution lines given in the conversation's system-reminder, when one is present.",
                "schema": {
                  "name": "Bash",
                  "description": "Executes a bash command and returns its output.\n\n- Working directory persists between calls, but prefer absolute paths — `cd` in a compound command can trigger a permission prompt. Shell state (env vars, functions) does not persist; the shell is initialized from the user's profile.\n- Command output is displayed to you, not reliably to the user.\n- `timeout` is in milliseconds: default 120000, max 600000.\n- `run_in_background` runs the command detached: it keeps running across turns and re-invokes you when it exits. No `&` needed.\n\n# Git\n- Interactive flags (`-i`, e.g. `git rebase -i`, `git add -i`) are not supported in this environment.\n- Use the `gh` CLI for GitHub operations (PRs, issues, API).\n- Commit or push only when the user asks. If on the default branch, branch first.\n- End git commit messages and PR bodies with the attribution lines given in the conversation's system-reminder, when one is present.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "command": {
                        "description": "The command to execute",
                        "type": "string"
                      },
                      "timeout": {
                        "description": "Optional timeout in milliseconds (max 600000)",
                        "type": "number"
                      },
                      "description": {
                        "description": "Clear, concise description of what this command does in active voice. Never use words like \"complex\" or \"risk\" in the description - just describe what it does.\n\nSay what the command does in plain words: do not echo the command's text, its flags, or file paths - the user reads this description, often without seeing the command.\n\nFor simple commands (git, npm, standard CLI tools), keep it brief (5-10 words):\n- ls → \"List files in current directory\"\n- git status → \"Show working tree status\"\n- npm install → \"Install package dependencies\"\n\nFor commands that are harder to parse at a glance (piped commands, obscure flags, etc.), add enough context to clarify what it does:\n- find . -name \"*.tmp\" -exec rm {} \\; → \"Find and delete all .tmp files recursively\"\n- git reset --hard origin/main → \"Discard all local changes and match remote main\"\n- curl -s url | jq '.data[]' → \"Fetch JSON from URL and extract data array elements\"",
                        "type": "string"
                      },
                      "run_in_background": {
                        "description": "Set to true to run this command in the background.",
                        "type": "boolean"
                      },
                      "dangerouslyDisableSandbox": {
                        "description": "Set this to true to dangerously override sandbox mode and run commands without sandboxing.",
                        "type": "boolean"
                      }
                    },
                    "required": [
                      "command"
                    ],
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "Edit",
                "description": "Performs exact string replacement in a file.\n\n- You must Read the file in this conversation before editing, or the call will fail.\n- `old_string` must match the file exactly, including indentation, and be unique — the edit fails otherwise. Strip the Read line prefix (line number + tab) before matching.\n- `replace_all: true` replaces every occurrence instead.",
                "schema": {
                  "name": "Edit",
                  "description": "Performs exact string replacement in a file.\n\n- You must Read the file in this conversation before editing, or the call will fail.\n- `old_string` must match the file exactly, including indentation, and be unique — the edit fails otherwise. Strip the Read line prefix (line number + tab) before matching.\n- `replace_all: true` replaces every occurrence instead.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "file_path": {
                        "description": "The absolute path to the file to modify",
                        "type": "string"
                      },
                      "old_string": {
                        "description": "The text to replace",
                        "type": "string"
                      },
                      "new_string": {
                        "description": "The text to replace it with (must be different from old_string)",
                        "type": "string"
                      },
                      "replace_all": {
                        "description": "Replace all occurrences of old_string (default false)",
                        "default": false,
                        "type": "boolean"
                      }
                    },
                    "required": [
                      "file_path",
                      "old_string",
                      "new_string"
                    ],
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "ListAgents",
                "description": "Lists agents you can SendMessage to — in-process subagents you spawned, the teammates on your team, other local Claude sessions on this machine, your Claude sessions running in the cloud (when this session has cloud access; a cloud session receives your message but cannot message any session back yet — do not ask it to reply, read its answer in its own transcript), and (when Remote Control is connected here) your account's other sessions — Remote Control sessions on other machines and cloud sessions, each row labeled by kind. Names are the address: send with `SendMessage({to: \"<name>\", message: \"...\"})`, copying the name exactly as a row prints it. Append a row's ` [ref]` only when the bare name is not enough — two rows share it, or an error asks you to disambiguate.",
                "schema": {
                  "name": "ListAgents",
                  "description": "Lists agents you can SendMessage to — in-process subagents you spawned, the teammates on your team, other local Claude sessions on this machine, your Claude sessions running in the cloud (when this session has cloud access; a cloud session receives your message but cannot message any session back yet — do not ask it to reply, read its answer in its own transcript), and (when Remote Control is connected here) your account's other sessions — Remote Control sessions on other machines and cloud sessions, each row labeled by kind. Names are the address: send with `SendMessage({to: \"<name>\", message: \"...\"})`, copying the name exactly as a row prints it. Append a row's ` [ref]` only when the bare name is not enough — two rows share it, or an error asks you to disambiguate.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "channel": {
                        "description": "Not available in this build; leave unset.",
                        "type": "string",
                        "maxLength": 256
                      },
                      "q": {
                        "description": "Not available in this build; leave unset.",
                        "type": "string",
                        "maxLength": 256
                      }
                    },
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "Read",
                "description": "Reads a file from the local filesystem.\n\n- `file_path` must be an absolute path.\n- Reads up to 2000 lines by default.\n- When you already know which part of the file you need, only read that part. This can be important for larger files.\n- Results are returned using cat -n format, with line numbers starting at 1\n- Reads images (PNG, JPG, …) and presents them visually. Reads PDFs via the `pages` parameter (e.g. \"1-5\", max 20 pages/request; required for PDFs over 10 pages). Reads Jupyter notebooks (.ipynb) as cells with outputs.\n- Reading a directory, a missing file, or an empty file returns an error or system reminder rather than content.\n- Do NOT re-read a file you just edited to verify — Edit/Write would have errored if the change failed, and the harness tracks file state for you.",
                "schema": {
                  "name": "Read",
                  "description": "Reads a file from the local filesystem.\n\n- `file_path` must be an absolute path.\n- Reads up to 2000 lines by default.\n- When you already know which part of the file you need, only read that part. This can be important for larger files.\n- Results are returned using cat -n format, with line numbers starting at 1\n- Reads images (PNG, JPG, …) and presents them visually. Reads PDFs via the `pages` parameter (e.g. \"1-5\", max 20 pages/request; required for PDFs over 10 pages). Reads Jupyter notebooks (.ipynb) as cells with outputs.\n- Reading a directory, a missing file, or an empty file returns an error or system reminder rather than content.\n- Do NOT re-read a file you just edited to verify — Edit/Write would have errored if the change failed, and the harness tracks file state for you.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "file_path": {
                        "description": "The absolute path to the file to read",
                        "type": "string"
                      },
                      "offset": {
                        "description": "The line number to start reading from. Only provide if the file is too large to read at once",
                        "type": "integer",
                        "minimum": 0,
                        "maximum": 9007199254740991
                      },
                      "limit": {
                        "description": "The number of lines to read. Only provide if the file is too large to read at once.",
                        "type": "integer",
                        "exclusiveMinimum": 0,
                        "maximum": 9007199254740991
                      },
                      "pages": {
                        "description": "Page range for PDF files (e.g., \"1-5\", \"3\", \"10-20\"). Only applicable to PDF files. Maximum 20 pages per request.",
                        "type": "string"
                      }
                    },
                    "required": [
                      "file_path"
                    ],
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "ReportFindings",
                "description": "Report code-review findings as a typed list so the host UI can render them. Use this only when the active code-review instructions tell you to report findings with this tool; otherwise follow whatever output format those instructions specify. When reporting a review's results, call it once with the verified findings ranked most-severe first (empty array if nothing survived verification) and do not also print the findings as text. When re-reporting after applying fixes (only if the apply instructions ask for it), set `outcome` on each finding to what actually happened.",
                "schema": {
                  "name": "ReportFindings",
                  "description": "Report code-review findings as a typed list so the host UI can render them. Use this only when the active code-review instructions tell you to report findings with this tool; otherwise follow whatever output format those instructions specify. When reporting a review's results, call it once with the verified findings ranked most-severe first (empty array if nothing survived verification) and do not also print the findings as text. When re-reporting after applying fixes (only if the apply instructions ask for it), set `outcome` on each finding to what actually happened.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "level": {
                        "description": "Effort level the review ran at",
                        "type": "string",
                        "enum": [
                          "low",
                          "medium",
                          "high",
                          "xhigh",
                          "max"
                        ]
                      },
                      "findings": {
                        "description": "Verified findings, most-severe first; empty if none survived",
                        "maxItems": 32,
                        "type": "array",
                        "items": {
                          "type": "object",
                          "properties": {
                            "file": {
                              "description": "Repo-relative path of the file the finding is in",
                              "type": "string"
                            },
                            "line": {
                              "description": "1-indexed line the finding anchors to",
                              "type": "integer",
                              "minimum": -9007199254740991,
                              "maximum": 9007199254740991
                            },
                            "summary": {
                              "description": "One-sentence statement of the defect",
                              "type": "string"
                            },
                            "short_summary": {
                              "description": "Compressed label for compact UI (≤60 chars): the claim alone, no rationale or consequence clause",
                              "type": "string",
                              "maxLength": 60
                            },
                            "failure_scenario": {
                              "description": "Concrete inputs/state → wrong output/crash",
                              "type": "string"
                            },
                            "category": {
                              "description": "Short kebab-case slug of the finding type, e.g. \"correctness\", \"simplification\", \"efficiency\", \"test-coverage\"",
                              "type": "string",
                              "maxLength": 40
                            },
                            "verdict": {
                              "description": "Set when a verify pass ran; absent on inline-only reviews",
                              "type": "string",
                              "enum": [
                                "CONFIRMED",
                                "PLAUSIBLE"
                              ]
                            },
                            "outcome": {
                              "description": "Set ONLY when re-reporting after applying fixes: what happened to this finding",
                              "type": "string",
                              "enum": [
                                "fixed",
                                "skipped",
                                "no_change_needed"
                              ]
                            }
                          },
                          "required": [
                            "file",
                            "summary",
                            "failure_scenario"
                          ],
                          "additionalProperties": false
                        }
                      }
                    },
                    "required": [
                      "findings"
                    ],
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "ScheduleWakeup",
                "description": "Schedule when to resume work in /loop dynamic mode — the user invoked /loop without an interval, asking you to self-pace iterations of a specific task.\n\nDo NOT schedule a short-interval wakeup to poll for background work you started — when harness-tracked work finishes, you are re-invoked automatically, so polling is wasted. Instead schedule a long fallback (1200s+) so the loop survives if the work hangs or never notifies. The exception is external work the harness cannot track (a CI run, a deploy, a remote queue) — there, pick a delay matched to how fast that state actually changes.\n\nPass the same /loop prompt back via `prompt` each turn so the next firing repeats the task. For an autonomous /loop (no user prompt), pass the literal sentinel `<<autonomous-loop-dynamic>>` as `prompt` instead — the runtime resolves it back to the autonomous-loop instructions at fire time. (There is a similar `<<autonomous-loop>>` sentinel for CronCreate-based autonomous loops; do not confuse the two — ScheduleWakeup always uses the `-dynamic` variant.) To end the loop, call this tool with `stop: true` (omit every other field) — the loop ends immediately and no further wakeups fire.\n\nSet `noop: true` if nothing changed — you checked and there's nothing to report (\"no change\", \"still waiting\", \"quiet hold\"). Set `noop: false` if something happened worth keeping — you edited a file, posted a message, advanced state, or surfaced a finding. Consecutive `noop: true` ticks are collapsed in the user's terminal view and tracked as a streak, so long quiet holds stay legible to the user without scrolling. Omit `noop` when stopping (`stop: true`).\n\n## Picking delaySeconds\n\nThis session's requests use a 1-hour Anthropic prompt-cache TTL, so effectively every allowed delay (the runtime clamps to [60, 3600]) wakes up with your conversation context still cached. There is no cache cliff inside that range to pace around, and scheduling extra wakeups just to keep the cache warm is pure waste — never do that. (If the session enters usage overage, later requests drop to the 5-minute TTL; don't try to track or preempt that — the guidance here stays the same.)\n\nMatch the delay to what you're actually waiting for:\n\n- **Actively polling external state the harness can't notify you about** (a CI run, a deploy, a remote queue): pick the delay from how fast that state actually changes. A CI run that takes ~8 minutes deserves one ~480s check, not eight 60s ones.\n- **The long fallback heartbeat** (something else — a Monitor, a task notification — is the primary wake signal): 1200s+, so quiet wakeups stay rare.\n- **Idle ticks with no specific signal to watch**: default to **1200s–1800s** (20–30 min). The loop still checks back regularly, and the user can always interrupt if they need you sooner.\n\nDon't think in cache windows — think about what you're actually waiting for.\n\n## The reason field\n\nOne short sentence on what you chose and why. Goes to telemetry and is shown back to the user. \"watching CI run\" beats \"waiting.\" The user reads this to understand what you're doing without having to predict your cadence in advance — make it specific.\n",
                "schema": {
                  "name": "ScheduleWakeup",
                  "description": "Schedule when to resume work in /loop dynamic mode — the user invoked /loop without an interval, asking you to self-pace iterations of a specific task.\n\nDo NOT schedule a short-interval wakeup to poll for background work you started — when harness-tracked work finishes, you are re-invoked automatically, so polling is wasted. Instead schedule a long fallback (1200s+) so the loop survives if the work hangs or never notifies. The exception is external work the harness cannot track (a CI run, a deploy, a remote queue) — there, pick a delay matched to how fast that state actually changes.\n\nPass the same /loop prompt back via `prompt` each turn so the next firing repeats the task. For an autonomous /loop (no user prompt), pass the literal sentinel `<<autonomous-loop-dynamic>>` as `prompt` instead — the runtime resolves it back to the autonomous-loop instructions at fire time. (There is a similar `<<autonomous-loop>>` sentinel for CronCreate-based autonomous loops; do not confuse the two — ScheduleWakeup always uses the `-dynamic` variant.) To end the loop, call this tool with `stop: true` (omit every other field) — the loop ends immediately and no further wakeups fire.\n\nSet `noop: true` if nothing changed — you checked and there's nothing to report (\"no change\", \"still waiting\", \"quiet hold\"). Set `noop: false` if something happened worth keeping — you edited a file, posted a message, advanced state, or surfaced a finding. Consecutive `noop: true` ticks are collapsed in the user's terminal view and tracked as a streak, so long quiet holds stay legible to the user without scrolling. Omit `noop` when stopping (`stop: true`).\n\n## Picking delaySeconds\n\nThis session's requests use a 1-hour Anthropic prompt-cache TTL, so effectively every allowed delay (the runtime clamps to [60, 3600]) wakes up with your conversation context still cached. There is no cache cliff inside that range to pace around, and scheduling extra wakeups just to keep the cache warm is pure waste — never do that. (If the session enters usage overage, later requests drop to the 5-minute TTL; don't try to track or preempt that — the guidance here stays the same.)\n\nMatch the delay to what you're actually waiting for:\n\n- **Actively polling external state the harness can't notify you about** (a CI run, a deploy, a remote queue): pick the delay from how fast that state actually changes. A CI run that takes ~8 minutes deserves one ~480s check, not eight 60s ones.\n- **The long fallback heartbeat** (something else — a Monitor, a task notification — is the primary wake signal): 1200s+, so quiet wakeups stay rare.\n- **Idle ticks with no specific signal to watch**: default to **1200s–1800s** (20–30 min). The loop still checks back regularly, and the user can always interrupt if they need you sooner.\n\nDon't think in cache windows — think about what you're actually waiting for.\n\n## The reason field\n\nOne short sentence on what you chose and why. Goes to telemetry and is shown back to the user. \"watching CI run\" beats \"waiting.\" The user reads this to understand what you're doing without having to predict your cadence in advance — make it specific.\n",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "delaySeconds": {
                        "description": "Seconds from now to wake up. Clamped to [60, 3600] by the runtime. Required unless `stop` is true.",
                        "type": "number"
                      },
                      "reason": {
                        "description": "One short sentence explaining the chosen delay. Goes to telemetry and is shown to the user. Be specific. Required unless `stop` is true.",
                        "type": "string"
                      },
                      "prompt": {
                        "description": "The /loop input to fire on wake-up. Pass the same /loop input verbatim each turn so the next firing re-enters the skill and continues the loop. For autonomous /loop (no user prompt), pass the literal sentinel `<<autonomous-loop-dynamic>>` instead (the dynamic-pacing variant, not the CronCreate-mode `<<autonomous-loop>>`). Required unless `stop` is true.",
                        "type": "string"
                      },
                      "stop": {
                        "description": "Set to true to end the dynamic loop immediately instead of scheduling another wakeup. When true, all other fields are ignored and no further wakeups fire.",
                        "type": "boolean"
                      },
                      "noop": {
                        "description": "true = nothing changed (you checked and there is nothing to report). false = something happened worth keeping (edited a file, posted a message, advanced state, surfaced a finding). Consecutive noop:true ticks are collapsed in the user's terminal view and tracked as a streak. Required unless `stop` is true.",
                        "type": "boolean"
                      }
                    },
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "Skill",
                "description": "Invoke a skill.\n\nA skill is a packaged set of instructions the user or project has set up for a particular kind of task (deploy steps, a review checklist, a repo-specific workflow). Available skills appear in a system-reminder listing with one-line descriptions. When the task at hand is one a listed skill covers, call this tool first — the skill's instructions load into the turn for you to follow in place of your default approach; some skills instead run in a subagent and return the finished result. A skill that runs in the background returns only the agent's name — its result arrives later as a task notification, so don't wait on it or invoke it again in the meantime. Users may also ask for one by name (`/<name>`, or \"slash command\"); that's a request to invoke it.\n\n- `skill`: exact name from the listing, no leading slash. Plugin skills use `plugin:skill`. Directory-scoped skills are listed with a path prefix (`apps/web:deploy`); when both scoped and unscoped variants of a name exist, pick the one whose directory contains the files you're working on (most specific wins; unscoped otherwise).\n- `args`: optional arguments to pass through.\n\nOnly names from the listing (or that the user typed explicitly) are valid. Built-in CLI commands (`/help`, `/clear`, …) aren't skills. If a `<command-name>` block is already present this turn, the skill is loaded — follow it directly rather than calling again.\n",
                "schema": {
                  "name": "Skill",
                  "description": "Invoke a skill.\n\nA skill is a packaged set of instructions the user or project has set up for a particular kind of task (deploy steps, a review checklist, a repo-specific workflow). Available skills appear in a system-reminder listing with one-line descriptions. When the task at hand is one a listed skill covers, call this tool first — the skill's instructions load into the turn for you to follow in place of your default approach; some skills instead run in a subagent and return the finished result. A skill that runs in the background returns only the agent's name — its result arrives later as a task notification, so don't wait on it or invoke it again in the meantime. Users may also ask for one by name (`/<name>`, or \"slash command\"); that's a request to invoke it.\n\n- `skill`: exact name from the listing, no leading slash. Plugin skills use `plugin:skill`. Directory-scoped skills are listed with a path prefix (`apps/web:deploy`); when both scoped and unscoped variants of a name exist, pick the one whose directory contains the files you're working on (most specific wins; unscoped otherwise).\n- `args`: optional arguments to pass through.\n\nOnly names from the listing (or that the user typed explicitly) are valid. Built-in CLI commands (`/help`, `/clear`, …) aren't skills. If a `<command-name>` block is already present this turn, the skill is loaded — follow it directly rather than calling again.\n",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "skill": {
                        "description": "The name of a skill from the available-skills list. Do not guess names.",
                        "type": "string"
                      },
                      "args": {
                        "description": "Optional arguments for the skill",
                        "type": "string"
                      }
                    },
                    "required": [
                      "skill"
                    ],
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "ToolSearch",
                "description": "Fetches full schema definitions for deferred tools so they can be called.\n\nDeferred tools appear by name in <system-reminder> messages. Until fetched, only the name is known — there is no parameter schema, so the tool cannot be invoked. This tool takes a query, matches it against the deferred tool list, and returns the matched tools' complete JSONSchema definitions inside a <functions> block. Once a tool's schema appears in that result, it is callable exactly like any tool defined at the top of the prompt.\n\nResult format: each matched tool appears as one <function>{\"description\": \"...\", \"name\": \"...\", \"parameters\": {...}}</function> line inside the <functions> block — the same encoding as the tool list at the top of this prompt.\n\nQuery forms:\n- \"select:Read,Edit,Grep\" — fetch these exact tools by name\n- \"notebook jupyter\" — keyword search, up to max_results best matches\n- \"+slack send\" — require \"slack\" in the name, rank by remaining terms",
                "schema": {
                  "name": "ToolSearch",
                  "description": "Fetches full schema definitions for deferred tools so they can be called.\n\nDeferred tools appear by name in <system-reminder> messages. Until fetched, only the name is known — there is no parameter schema, so the tool cannot be invoked. This tool takes a query, matches it against the deferred tool list, and returns the matched tools' complete JSONSchema definitions inside a <functions> block. Once a tool's schema appears in that result, it is callable exactly like any tool defined at the top of the prompt.\n\nResult format: each matched tool appears as one <function>{\"description\": \"...\", \"name\": \"...\", \"parameters\": {...}}</function> line inside the <functions> block — the same encoding as the tool list at the top of this prompt.\n\nQuery forms:\n- \"select:Read,Edit,Grep\" — fetch these exact tools by name\n- \"notebook jupyter\" — keyword search, up to max_results best matches\n- \"+slack send\" — require \"slack\" in the name, rank by remaining terms",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "query": {
                        "description": "Query to find deferred tools. Use \"select:<tool_name>\" for direct selection, or keywords to search.",
                        "type": "string"
                      },
                      "max_results": {
                        "description": "Maximum number of results to return (default: 5)",
                        "default": 5,
                        "type": "number"
                      }
                    },
                    "required": [
                      "query",
                      "max_results"
                    ],
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "Workflow",
                "description": "Execute a workflow script that orchestrates multiple subagents deterministically. Workflows run in the background — this tool returns immediately with a task ID, and a <task-notification> arrives when the workflow completes. Use /workflows to watch live progress.\n\nONLY call this tool when the user has explicitly opted into multi-agent orchestration. Workflows can spawn dozens of agents and consume a large amount of tokens; the user must request that scale, not have it inferred. Explicit opt-in means one of:\n- The user included the keyword \"ultracode\" in their prompt (you'll see a system-reminder confirming it).\n- Ultracode is on for the session (a system-reminder confirms it) — see **Ultracode** in the workflow authoring reference.\n- The user directly asked you to run a workflow or use multi-agent orchestration in their own words (\"use a workflow\", \"run a workflow\", \"fan out agents\", \"orchestrate this with subagents\"). The ask must be in the user's words — a task that would merely benefit from a workflow does not count.\n- The user invoked a skill or slash command whose instructions tell you to call Workflow.\n- The user asked you to run a specific named or saved workflow.\n\nFor any other task — even one that would clearly benefit from parallelism — do NOT call this tool. Use the Agent tool (if available) for individual subagents, or briefly describe what a multi-agent workflow could do and how much it would roughly cost, and ask the user whether to run it. Mention they can ask for one with \"use a workflow\" in a future message to skip the ask.\n\nEvery script must begin with `export const meta = {...}`: a PURE LITERAL (no variables, calls or interpolation) giving the workflow's `name`, a one-line `description` (shown in the permission dialog) and optionally `phases` — one `{ title, detail? }` per phase() call, titles matched exactly. Pass the script inline via `script` — do not Write it to a file first, and do not also set the tool's `name` input (that selects a saved workflow); it is plain JavaScript, not TypeScript.\n\nThe canonical multi-stage pattern — pipeline by default, each dimension verifies as soon as its review completes:\n  export const meta = {\n    name: 'review-changes',\n    description: 'Review changed files across dimensions, verify each finding',\n    phases: [{ title: 'Review' }, { title: 'Verify' }],\n  }\n  const DIMENSIONS = [{key: 'bugs', prompt: '...'}, {key: 'perf', prompt: '...'}]\n  const results = await pipeline(\n    DIMENSIONS,\n    d => agent(d.prompt, {label: `review:${d.key}`, phase: 'Review', schema: FINDINGS_SCHEMA}),\n    review => parallel(review.findings.map(f => () =>\n      agent(`Adversarially verify: ${f.title}`, {label: `verify:${f.file}`, phase: 'Verify', schema: VERDICT_SCHEMA})\n        .then(v => ({...f, verdict: v}))\n    ))\n  )\n  const confirmed = results.flat().filter(Boolean).filter(f => f.verdict?.isReal)\n  return { confirmed }\n  // Dimension 'bugs' findings verify while dimension 'perf' is still reviewing. No wasted wall-clock.\n\nBefore writing a script, load the `workflow-authoring` skill — the workflow authoring reference: script API and gotchas, resume, the **Ultracode** section, quality patterns, worked examples.\n\nThis session has the default workflow size guideline: medium — keep workflows under 10 agents. This is a guideline, not a hard limit — follow it unless the user's prompt calls for a different scale. The user can raise or remove it with \"Dynamic workflow size\" in /config.",
                "schema": {
                  "name": "Workflow",
                  "description": "Execute a workflow script that orchestrates multiple subagents deterministically. Workflows run in the background — this tool returns immediately with a task ID, and a <task-notification> arrives when the workflow completes. Use /workflows to watch live progress.\n\nONLY call this tool when the user has explicitly opted into multi-agent orchestration. Workflows can spawn dozens of agents and consume a large amount of tokens; the user must request that scale, not have it inferred. Explicit opt-in means one of:\n- The user included the keyword \"ultracode\" in their prompt (you'll see a system-reminder confirming it).\n- Ultracode is on for the session (a system-reminder confirms it) — see **Ultracode** in the workflow authoring reference.\n- The user directly asked you to run a workflow or use multi-agent orchestration in their own words (\"use a workflow\", \"run a workflow\", \"fan out agents\", \"orchestrate this with subagents\"). The ask must be in the user's words — a task that would merely benefit from a workflow does not count.\n- The user invoked a skill or slash command whose instructions tell you to call Workflow.\n- The user asked you to run a specific named or saved workflow.\n\nFor any other task — even one that would clearly benefit from parallelism — do NOT call this tool. Use the Agent tool (if available) for individual subagents, or briefly describe what a multi-agent workflow could do and how much it would roughly cost, and ask the user whether to run it. Mention they can ask for one with \"use a workflow\" in a future message to skip the ask.\n\nEvery script must begin with `export const meta = {...}`: a PURE LITERAL (no variables, calls or interpolation) giving the workflow's `name`, a one-line `description` (shown in the permission dialog) and optionally `phases` — one `{ title, detail? }` per phase() call, titles matched exactly. Pass the script inline via `script` — do not Write it to a file first, and do not also set the tool's `name` input (that selects a saved workflow); it is plain JavaScript, not TypeScript.\n\nThe canonical multi-stage pattern — pipeline by default, each dimension verifies as soon as its review completes:\n  export const meta = {\n    name: 'review-changes',\n    description: 'Review changed files across dimensions, verify each finding',\n    phases: [{ title: 'Review' }, { title: 'Verify' }],\n  }\n  const DIMENSIONS = [{key: 'bugs', prompt: '...'}, {key: 'perf', prompt: '...'}]\n  const results = await pipeline(\n    DIMENSIONS,\n    d => agent(d.prompt, {label: `review:${d.key}`, phase: 'Review', schema: FINDINGS_SCHEMA}),\n    review => parallel(review.findings.map(f => () =>\n      agent(`Adversarially verify: ${f.title}`, {label: `verify:${f.file}`, phase: 'Verify', schema: VERDICT_SCHEMA})\n        .then(v => ({...f, verdict: v}))\n    ))\n  )\n  const confirmed = results.flat().filter(Boolean).filter(f => f.verdict?.isReal)\n  return { confirmed }\n  // Dimension 'bugs' findings verify while dimension 'perf' is still reviewing. No wasted wall-clock.\n\nBefore writing a script, load the `workflow-authoring` skill — the workflow authoring reference: script API and gotchas, resume, the **Ultracode** section, quality patterns, worked examples.\n\nThis session has the default workflow size guideline: medium — keep workflows under 10 agents. This is a guideline, not a hard limit — follow it unless the user's prompt calls for a different scale. The user can raise or remove it with \"Dynamic workflow size\" in /config.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "script": {
                        "description": "Self-contained workflow script. Must begin with `export const meta = { name, description, phases }` (pure literal, no computed values) followed by the script body using agent()/parallel()/pipeline()/phase().",
                        "type": "string",
                        "maxLength": 524288
                      },
                      "name": {
                        "description": "Name of a predefined workflow (built-in or from .claude/workflows/). Resolves to a self-contained script.",
                        "type": "string"
                      },
                      "description": {
                        "description": "Ignored — set the workflow description in the script's `meta` block.",
                        "type": "string"
                      },
                      "title": {
                        "description": "Ignored — set the workflow title in the script's `meta` block.",
                        "type": "string"
                      },
                      "args": {
                        "description": "Optional input value exposed to the script as the global `args`, verbatim. Pass arrays/objects as actual JSON values, NOT as a JSON-encoded string — a stringified list breaks `args.filter`/`args.map` in the script. Use for parameterized named workflows (e.g. a research question)."
                      },
                      "scriptPath": {
                        "description": "Path to a workflow script file on disk. Every Workflow invocation persists its script under the session directory and returns the path in the tool result. To iterate, edit that file with Write/Edit and re-invoke Workflow with the same `scriptPath` instead of re-sending the full script. Takes precedence over `script` and `name`.",
                        "type": "string"
                      },
                      "resumeFromRunId": {
                        "description": "Run ID of a prior Workflow invocation to resume from. Completed agent() calls with unchanged (prompt, opts) return their cached results instantly; only edited or new calls re-run. Same-session only. Stop the prior run first (TaskStop) before resuming.",
                        "type": "string",
                        "pattern": "^wf_[a-z0-9-]{6,}$"
                      }
                    },
                    "additionalProperties": false
                  }
                }
              },
              {
                "name": "Write",
                "description": "Writes a file to the local filesystem, overwriting if one exists.\n\nWhen to use: creating a new file, or fully replacing one you've already Read. Overwriting an existing file you haven't Read will fail. For partial changes, use Edit instead.",
                "schema": {
                  "name": "Write",
                  "description": "Writes a file to the local filesystem, overwriting if one exists.\n\nWhen to use: creating a new file, or fully replacing one you've already Read. Overwriting an existing file you haven't Read will fail. For partial changes, use Edit instead.",
                  "input_schema": {
                    "$schema": "https://json-schema.org/draft/2020-12/schema",
                    "type": "object",
                    "properties": {
                      "file_path": {
                        "description": "The absolute path to the file to write (must be absolute, not relative)",
                        "type": "string"
                      },
                      "content": {
                        "description": "The content to write to the file",
                        "type": "string"
                      }
                    },
                    "required": [
                      "file_path",
                      "content"
                    ],
                    "additionalProperties": false
                  }
                }
              }
            ],
            "cliPrefix": "You are a Claude agent, built on Anthropic's Claude Agent SDK.",
            "reminderFold": false,
            "systemTurns": true,
            "toolChangeHeader": true,
            "inlineTools": false,
            "keptReminders": true,
            "echoWireToolInputs": false,
            "contextRendering": "announced"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:02:52.846Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14982207 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 3,
      "role": "agent",
      "timestamp": "2026-09-26T09:02:55.655Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:02:55.655Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:02:58.540Z",
          "callId": "toolu_01MJZJuERbAnh3eua4DJTbXw",
          "name": "Bash",
          "input": {
            "command": "mkdir -p /app/solution; cd /app/solution; cat > prep.py <<'EOF'\nimport pandas as pd, numpy as np\nD='/task/data/'\ncat=pd.read_parquet(D+'candidate_catalog.parquet'); items=cat.item_id.values\ntu=pd.read_parquet(D+'target_users.parquet').uid.values\niid={int(x):i for i,x in enumerate(items)}\nfor split in ['train','val']:\n    l=pd.read_parquet(D+f'{split}_listens.parquet')\n    l=l[l.item_id.isin(items)]\n    l['iidx']=pd.Series(pd.Categorical(l.item_id,categories=items).codes,index=l.index).astype(np.int32)\n    l.drop(columns=['item_id']).to_parquet(f'/app/solution/{split}_listens_cat.parquet')\n    print(split,len(l), l.uid.nunique())\nEOF\npython prep.py; ls -la"
          },
          "result": {
            "timestamp": "2026-09-26T09:03:07.858Z",
            "content": "train 31249613 9217\nval 1011771 7947\ntotal 383396\ndrwxr-xr-x 1 agent agent      4096 Sep 26 09:03 .\ndrwxr-xr-x 1 agent agent      4096 Sep 26 08:58 ..\n-rw-r--r-- 1 agent agent       573 Sep 26 09:02 prep.py\n-rw-r--r-- 1 agent agent 382045139 Sep 26 09:03 train_listens_cat.parquet\n-rw-r--r-- 1 agent agent  10531150 Sep 26 09:03 val_listens_cat.parquet",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:03:07.862Z",
          "data": {
            "type": "environment",
            "snapshot": {
              "workingDirectory": "/app/solution",
              "isWorktree": false,
              "isGitRepo": false,
              "additionalWorkingDirectories": [],
              "platform": "linux",
              "shell": "unknown",
              "osVersion": "Linux 7.0.0-1013-aws"
            },
            "changes": [
              {
                "field": "workingDirectory",
                "from": "/app"
              }
            ]
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:03:07.863Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14976728 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 4,
      "role": "agent",
      "timestamp": "2026-09-26T09:03:09.439Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:03:09.439Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:03:15.633Z",
          "callId": "toolu_018yrPLFo9mBr9AseMni3PkW",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; cat > ana.py <<'EOF'\nimport pandas as pd, numpy as np\nD='/task/data/'\nitems=pd.read_parquet(D+'candidate_catalog.parquet').item_id.values\nz=np.load(D+'validation_eligible_candidates.npz'); assert (z['item_ids']==items).all()\nM=np.unpackbits(z['packed_eligible'],axis=1,count=30000,bitorder='little').astype(bool)\nuids=z['uids']; urow={int(u):i for i,u in enumerate(uids)}\ntr=pd.read_parquet('train_listens_cat.parquet',columns=['uid','iidx','played_ratio_pct','is_organic','timestamp'])\ntr=tr[tr.uid.isin(uids)]\nr=tr.uid.map(urow).values\nelig=M[r,tr.iidx.values]\nprint('frac train listens eligible',elig.mean())\npos=tr.played_ratio_pct.values>=50\nprint('frac pos listens eligible',elig[pos].mean())\n# per pair\npairs=tr[['uid','iidx']].drop_duplicates(); pr=pairs.uid.map(urow).values\nprint('frac pairs eligible', M[pr,pairs.iidx.values].mean(), len(pairs))\nps=pd.read_parquet(D+'validation_preference_state.parquet'); ps=ps[ps.item_id.isin(items)]\nps['iidx']=pd.Categorical(ps.item_id,categories=items).codes\nfor s in ['liked','disliked']:\n    q=ps[ps.state==s]; print(s,len(q),M[q.uid.map(urow).values,q.iidx.values].mean())\nva=pd.read_parquet('val_listens_cat.parquet'); va=va[va.uid.isin(uids)&(va.is_organic==1)&(va.played_ratio_pct>=80)]\nvp=va[['uid','iidx']].drop_duplicates(); vr=vp.uid.map(urow).values\ne=M[vr,vp.iidx.values]; vp=vp[e]\nseen=set(zip(pairs.uid.values,pairs.iidx.values))\nprint('val relevant eligible pairs',len(vp),'frac seen in train',np.mean([(a,b) in seen for a,b in zip(vp.uid.values,vp.iidx.values)]))\nprint('ts range', tr.timestamp.min(), tr.timestamp.max())\nEOF\npython ana.py"
          },
          "result": {
            "timestamp": "2026-09-26T09:03:28.049Z",
            "content": "frac train listens eligible 0.0\nfrac pos listens eligible 0.0\nfrac pairs eligible 0.0 7868664\nliked 418435 0.0\ndisliked 50689 0.0\nval relevant eligible pairs 35597 frac seen in train 0.0\nts range 5 24786795",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:03:28.052Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14975524 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 5,
      "role": "agent",
      "timestamp": "2026-09-26T09:03:55.465Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:03:55.465Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:03:56.549Z",
          "callId": "toolu_014JKVXnWCpfbPVkzAEttSE9",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; python -c \"\nimport pandas as pd\nfor f in ['val_listens','val_likes']:\n    d=pd.read_parquet('/task/data/'+f+'.parquet',columns=['timestamp']); print(f,d.timestamp.min(),d.timestamp.max())\n\"; sed -n 1,60p /task/ranking_evaluation.py | grep -n \"def \\|class\" "
          },
          "result": {
            "timestamp": "2026-09-26T09:03:58.123Z",
            "content": "val_listens 24788600 25393395\nval_likes 24788815 25393390\n39:class RankingValidationError(ValueError):\n43:class CandidateSet:\n52:    def __init__(self, path: Path):",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:03:58.125Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14972919 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 6,
      "role": "agent",
      "timestamp": "2026-09-26T09:04:17.786Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:04:17.786Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:04:44.678Z",
          "callId": "toolu_01KJVuQAzvP26fPrrrJGPLbF",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; cat > data.py <<'EOF'\n\"\"\"Cutoff-correct feature/target construction for the two-tower model (no global interaction matrix).\"\"\"\nimport numpy as np, pandas as pd\nD = '/task/data/'\nNI = 30000\nDAY = 86400\nGAP = 1800\nWIN = 7 * DAY\nKP, KO, KL, KD, KS = 256, 64, 128, 64, 64   # bag sizes: positive, organic-positive, liked, disliked, skipped\n\nITEMS = pd.read_parquet(D + 'candidate_catalog.parquet').item_id.values\n\n\ndef to_idx(s):\n    return pd.Categorical(s, categories=ITEMS).codes.astype(np.int32)\n\n\ndef load(stage):\n    \"\"\"stage='val': train_* only; stage='test': train_* + val_*.\"\"\"\n    parts = ['train'] + (['val'] if stage == 'test' else [])\n    L = pd.concat([pd.read_parquet(f'/app/solution/{p}_listens_cat.parquet') for p in parts], ignore_index=True)\n    ev = {}\n    for f in ['likes', 'dislikes', 'unlikes', 'undislikes']:\n        x = pd.concat([pd.read_parquet(D + f'{p}_{f}.parquet') for p in parts], ignore_index=True)\n        x = x[x.item_id.isin(ITEMS)].copy(); x['iidx'] = to_idx(x.item_id)\n        ev[f] = x\n    return L, ev\n\n\ndef active_state(ev, pos, neg, c):\n    a = ev[pos][ev[pos].timestamp < c].groupby(['uid', 'iidx']).timestamp.max()\n    b = ev[neg][ev[neg].timestamp < c].groupby(['uid', 'iidx']).timestamp.max()\n    j = pd.concat([a.rename('a'), b.rename('b')], axis=1).fillna(-1)\n    j = j[j.a > j.b].reset_index()\n    return j[['uid', 'iidx', 'a']]\n\n\ndef topk_bag(u_rows, items, score, nU, K):\n    \"\"\"Per user keep top-K items by score -> padded [nU,K] (item+1, 0=pad) and rank arrays.\"\"\"\n    o = np.lexsort((-score, u_rows))\n    u_rows, items, score = u_rows[o], items[o], score[o]\n    start = np.searchsorted(u_rows, np.arange(nU))\n    pos = np.arange(len(u_rows)) - start[u_rows]\n    keep = pos < K\n    bag = np.zeros((nU, K), np.int32); w = np.zeros((nU, K), np.float32)\n    bag[u_rows[keep], pos[keep]] = items[keep] + 1\n    w[u_rows[keep], pos[keep]] = score[keep]\n    return bag, w\n\n\ndef build(L, ev, uids, c, targets=True):\n    \"\"\"Features at cutoff c for users `uids` (history = events with ts < c).\"\"\"\n    urow = pd.Series(np.arange(len(uids)), index=uids)\n    nU = len(uids)\n    h = L[L.timestamp.values < c]\n    ts = h.timestamp.values; ii = h.iidx.values; pr = h.played_ratio_pct.values; org = h.is_organic.values\n    posm = pr >= 50\n    # ---- item features (from all history, computed offline per cutoff)\n    age = (c - ts).astype(np.float64)\n    def cnt(m): return np.bincount(ii[m], minlength=NI).astype(np.float64)\n    f = []\n    for win in [None, 30 * DAY, 7 * DAY, 1 * DAY]:\n        m = posm if win is None else posm & (age < win)\n        f.append(np.log1p(cnt(m)))\n        f.append(np.log1p(cnt(m & (org == 1) & (pr >= 80))))\n    allc = cnt(np.ones(len(ii), bool)); f.append(np.log1p(allc))\n    f.append(cnt(posm) / np.maximum(allc, 1))\n    first = pd.Series(ts).groupby(ii).min().reindex(range(NI)).fillna(c).values\n    f.append(np.log1p((c - first) / DAY))\n    lk = ev['likes']; lk = lk[lk.timestamp < c]\n    f.append(np.log1p(np.bincount(lk.iidx.values, minlength=NI)))\n    f.append(np.log1p(np.bincount(lk.iidx.values[(c - lk.timestamp.values) < 7 * DAY], minlength=NI)))\n    dk = ev['dislikes']; dk = dk[dk.timestamp < c]\n    f.append(np.log1p(np.bincount(dk.iidx.values, minlength=NI)))\n    tl = pd.Series(h.track_length_seconds.values).groupby(ii).median().reindex(range(NI)).fillna(200).values\n    f.append(np.log1p(tl) - 5)\n    item_feat = np.stack(f, 1).astype(np.float32)\n    # ---- user bags\n    sel = h.uid.isin(uids).values\n    hu = urow.reindex(h.uid.values[sel]).values; hi = ii[sel]; hts = ts[sel]; hp = posm[sel]; ho = org[sel]\n    key = hu.astype(np.int64) * NI + hi\n    uk, inv = np.unique(key, return_inverse=True)\n    npos = np.bincount(inv, weights=hp); nplay = np.bincount(inv)\n    norg = np.bincount(inv, weights=hp & (ho == 1))\n    last = np.zeros(len(uk)); np.maximum.at(last, inv, hts)\n    ku = (uk // NI).astype(np.int64); ki = (uk % NI).astype(np.int32)\n    rec = np.exp(-(c - last) / (30 * DAY))\n    bags = {}\n    m = npos > 0\n    sc = (np.log1p(npos) * (0.3 + rec))[m]\n    bags['pos'] = topk_bag(ku[m], ki[m], sc, nU, KP)\n    m = norg > 0\n    bags['org'] = topk_bag(ku[m], ki[m], (np.log1p(norg) * (0.3 + rec))[m], nU, KO)\n    m = npos == 0\n    bags['skip'] = topk_bag(ku[m], ki[m], (np.log1p(nplay) * (0.3 + rec))[m], nU, KS)\n    liked = active_state(ev, 'likes', 'unlikes', c); liked = liked[liked.uid.isin(uids)]\n    disl = active_state(ev, 'dislikes', 'undislikes', c); disl = disl[disl.uid.isin(uids)]\n    lr = urow.reindex(liked.uid.values).values\n    bags['like'] = topk_bag(lr, liked.iidx.values, np.exp(-(c - liked.a.values) / (60 * DAY)) + 0.1, nU, KL)\n    dr = urow.reindex(disl.uid.values).values\n    bags['dis'] = topk_bag(dr, disl.iidx.values, np.exp(-(c - disl.a.values) / (60 * DAY)) + 0.1, nU, KD)\n    # user dense feats\n    uf = np.stack([np.log1p(np.bincount(ku, weights=npos, minlength=nU)),\n                   np.log1p(np.bincount(ku, minlength=nU)),\n                   np.log1p(np.bincount(hu[(c - hts) < 7 * DAY], minlength=nU)),\n                   np.log1p(np.bincount(hu[(c - hts) < 30 * DAY], minlength=nU)),\n                   np.bincount(ku, weights=norg, minlength=nU) / np.maximum(np.bincount(ku, weights=npos, minlength=nU), 1),\n                   np.log1p(np.bincount(lr, minlength=nU))], 1).astype(np.float32)\n    # seen set (ineligible): any listen, active like/dislike\n    seen_u = np.concatenate([ku, lr, dr]); seen_i = np.concatenate([ki, liked.iidx.values, disl.iidx.values])\n    out = dict(uids=np.asarray(uids), item_feat=item_feat, user_feat=uf, bags=bags, seen=(seen_u, seen_i), cutoff=c)\n    if targets:\n        t0, t1 = c + GAP, c + GAP + WIN\n        w = L[(L.timestamp.values >= t0) & (L.timestamp.values < t1) & (L.is_organic.values == 1)\n              & (L.played_ratio_pct.values >= 80) & L.uid.isin(uids).values]\n        tl_ = ev['likes']; tl_ = tl_[(tl_.timestamp >= t0) & (tl_.timestamp < t1) & (tl_.is_organic == 1) & tl_.uid.isin(uids)]\n        t = pd.concat([pd.DataFrame({'u': urow.reindex(w.uid.values).values, 'i': w.iidx.values, 'g': 1}),\n                       pd.DataFrame({'u': urow.reindex(tl_.uid.values).values, 'i': tl_.iidx.values, 'g': 3})])\n        t = t.groupby(['u', 'i']).g.max().reset_index()\n        tk = t.u.values.astype(np.int64) * NI + t.i.values\n        sk = np.unique(seen_u.astype(np.int64) * NI + seen_i)\n        t = t[~np.isin(tk, sk)]\n        out['targets'] = (t.u.values, t.i.values, (2.0 ** t.g.values - 1).astype(np.float32))\n    return out\nEOF\ncat > t.py <<'EOF'\nimport time, numpy as np, pandas as pd\nfrom data import *\nt=time.time(); L,ev=load('val'); print('load',time.time()-t)\nuids=np.sort(L.uid.unique())\nt=time.time(); o=build(L,ev,uids,24786800-WIN-GAP); print('build',time.time()-t)\nprint(o['item_feat'].mean(0), o['user_feat'].mean(0), len(o['targets'][0]), len(np.unique(o['targets'][0])))\nprint({k:(v[0]>0).sum(1).mean() for k,v in o['bags'].items()})\nEOF\npython t.py"
          },
          "result": {
            "timestamp": "2026-09-26T09:04:57.661Z",
            "content": "load 0.8488881587982178\nbuild 10.330952405929565\n[6.029683   5.0051026  3.8606656  2.9072993  2.4682643  1.6246665\n 0.97260445 0.52593285 6.4534063  0.6623822  5.48297    2.347974\n 0.29480308 0.7966357  0.2789378 ] [6.523133  6.073473  3.349556  4.9508786 0.5097718 2.3606722] 42013 4353\n{'pos': np.float64(197.2101551480959), 'org': np.float64(49.74362590864707), 'skip': np.float64(51.67842031029619), 'like': np.float64(32.781165238146905), 'dis': np.float64(3.6032331561245523)}",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:04:57.664Z",
          "data": {
            "type": "silent_turn_reminder",
            "text": "The user hasn't heard from you in a while. As you continue, keep them updated when there's something to tell — a finding, a change of plan."
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:04:57.664Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14967516 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 7,
      "role": "agent",
      "timestamp": "2026-09-26T09:05:12.991Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:05:12.991Z",
          "text": ""
        },
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:05:12.995Z",
          "text": "Data pipeline is cutoff-correct and builds quickly (~10s per cutoff), with eligibility properly excluding previously listened/liked/disliked items for a pure discovery task. Now I'll build the two-tower training script.\n\n"
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:05:35.862Z",
          "callId": "toolu_011jECcdZWThuxmUKHsVewJH",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; cat > train.py <<'EOF'\n\"\"\"Two-tower ranker: train on multiple historical cutoffs, rank at the stage cutoff.\nusage: python train.py val|test [epochs]\"\"\"\nimport sys, os, time, pickle, numpy as np, pandas as pd, torch, torch.nn as nn, torch.nn.functional as F\nfrom multiprocessing import Pool\nfrom data import *\ntorch.set_num_threads(8); torch.manual_seed(0); np.random.seed(0)\nSTAGE = sys.argv[1]; EPOCHS = int(sys.argv[2]) if len(sys.argv) > 2 else 8\nCUT = {'val': 24786800, 'test': 25393400}[STAGE]\nNCUT, STEP = int(os.environ.get('NCUT', 16)), int(3.5 * DAY)\nBAGS = ['pos', 'org', 'skip', 'like', 'dis']\nDIM = 64\n\n_G = {}\ndef _init(stage): _G['L'], _G['ev'] = load(stage); _G['uids'] = np.sort(_G['L'].uid.unique())\ndef _build(c): return build(_G['L'], _G['ev'], _G['uids'], c, targets=True)\n\ndef get_train_sets():\n    fn = f'/app/solution/cache_{STAGE}_{NCUT}.pkl'\n    if os.path.exists(fn): return pickle.load(open(fn, 'rb'))\n    cuts = [CUT - WIN - GAP - k * STEP for k in range(NCUT)]\n    with Pool(4, initializer=_init, initargs=(STAGE,)) as p: sets = p.map(_build, cuts)\n    pickle.dump(sets, open(fn, 'wb'), protocol=4); return sets\n\n\nclass UserTower(nn.Module):\n    \"\"\"Builds the user vector from interaction history bags (no user-ID lookup).\"\"\"\n    def __init__(self, nuf):\n        super().__init__()\n        self.emb = nn.Embedding(NI + 1, DIM, padding_idx=0)\n        nn.init.normal_(self.emb.weight, std=0.05)\n        self.mlp = nn.Sequential(nn.Linear(DIM * len(BAGS) + nuf, 256), nn.GELU(), nn.Dropout(0.2),\n                                 nn.Linear(256, 256), nn.GELU(), nn.Linear(256, DIM))\n    def forward(self, bags, ws, uf):\n        pooled = []\n        for b, w in zip(bags, ws):\n            wn = w / w.sum(1, keepdim=True).clamp_min(1e-6)\n            pooled.append((self.emb(b) * wn.unsqueeze(-1)).sum(1))\n        return self.mlp(torch.cat(pooled + [uf], 1))\n\n\nclass ItemTower(nn.Module):\n    \"\"\"Item vector from item-ID embedding + cutoff-time item statistics; precomputable offline.\"\"\"\n    def __init__(self, nif):\n        super().__init__()\n        self.emb = nn.Embedding(NI, DIM); nn.init.normal_(self.emb.weight, std=0.05)\n        self.fmlp = nn.Sequential(nn.Linear(nif, 64), nn.GELU())\n        self.mlp = nn.Sequential(nn.Linear(DIM + 64, 256), nn.GELU(), nn.Dropout(0.1), nn.Linear(256, DIM))\n        self.edrop = nn.Dropout(0.3)\n    def forward(self, feat):\n        return self.mlp(torch.cat([self.edrop(self.emb.weight), self.fmlp(feat)], 1))\n\n\ndef to_t(s):\n    \"\"\"Convert a cutoff set to tensors.\"\"\"\n    r = dict(item_feat=torch.from_numpy(s['item_feat']), user_feat=torch.from_numpy(s['user_feat']),\n             bags=[torch.from_numpy(s['bags'][b][0]).long() for b in BAGS],\n             ws=[torch.from_numpy(s['bags'][b][1]) for b in BAGS])\n    su, si = s['seen']; r['seen'] = (su, si)\n    return r\n\ndef seen_mask(s, rows):\n    su, si = s['seen']\n    pos = {u: k for k, u in enumerate(rows)}\n    m = np.isin(su, rows)\n    M = torch.zeros(len(rows), NI, dtype=torch.bool)\n    M[torch.from_numpy(np.vectorize(pos.get)(su[m]) if m.any() else np.zeros(0, int)).long(), torch.from_numpy(si[m]).long()] = True\n    return M\n\ndef user_vec(ut, T, rows):\n    r = torch.from_numpy(rows).long()\n    return ut([b[r] for b in T['bags']], [w[r] for w in T['ws']], T['user_feat'][r])\n\n\ndef main():\n    t0 = time.time()\n    sets = get_train_sets(); print('built', len(sets), 'cutoffs', time.time() - t0, flush=True)\n    # normalisation stats\n    fmu = np.mean([s['item_feat'].mean(0) for s in sets], 0); fsd = np.mean([s['item_feat'].std(0) for s in sets], 0) + 1e-6\n    umu = np.mean([s['user_feat'].mean(0) for s in sets], 0); usd = np.mean([s['user_feat'].std(0) for s in sets], 0) + 1e-6\n    for s in sets:\n        s['item_feat'] = (s['item_feat'] - fmu) / fsd; s['user_feat'] = (s['user_feat'] - umu) / usd\n    Ts = [to_t(s) for s in sets]\n    # per-set target lists\n    tgt = []\n    for s in sets:\n        u, i, g = s['targets']; df = pd.DataFrame({'u': u, 'i': i, 'g': g})\n        tgt.append({k: (v.i.values, v.g.values) for k, v in df.groupby('u')})\n    nif, nuf = sets[0]['item_feat'].shape[1], sets[0]['user_feat'].shape[1]\n    ut, it = UserTower(nuf), ItemTower(nif)\n    params = list(ut.parameters()) + list(it.parameters())\n    opt = torch.optim.AdamW(params, lr=2e-3, weight_decay=1e-5)\n    BS = 256\n    batches = []\n    for k, tg in enumerate(tgt):\n        rows = np.array(sorted(tg)); \n        for j in range(0, len(rows), BS): batches.append((k, j))\n    total = EPOCHS * len(batches); sched = torch.optim.lr_scheduler.OneCycleLR(opt, 2e-3, total_steps=total, pct_start=0.1)\n    step = 0\n    for ep in range(EPOCHS):\n        ut.train(); it.train(); tl = 0\n        order = np.random.permutation(len(batches))\n        perms = [np.random.permutation(np.array(sorted(tg))) for tg in tgt]\n        for bi in order:\n            k, j = batches[bi]; rows = perms[k][j:j + BS]; T = Ts[k]\n            u = user_vec(ut, T, rows); v = it(T['item_feat'])\n            logits = u @ v.T\n            logits = logits.masked_fill(seen_mask(sets[k], rows), -1e4)\n            Y = torch.zeros(len(rows), NI)\n            for a, r in enumerate(rows):\n                ii, gg = tgt[k][r]; Y[a, ii] = torch.from_numpy(gg)\n            Y = Y / Y.sum(1, keepdim=True)\n            loss = -(Y * F.log_softmax(logits, 1)).sum(1).mean()\n            opt.zero_grad(); loss.backward(); opt.step(); sched.step(); step += 1; tl += loss.item()\n        print(f'ep {ep} loss {tl / len(batches):.4f} t {time.time() - t0:.0f}', flush=True)\n    # ---- inference at stage cutoff\n    L, ev = load(STAGE)\n    targ = np.sort(pd.read_parquet(D + 'target_users.parquet').uid.values.astype(np.int64))\n    s = build(L, ev, targ, CUT, targets=False)\n    s['item_feat'] = (s['item_feat'] - fmu) / fsd; s['user_feat'] = (s['user_feat'] - umu) / usd\n    T = to_t(s); ut.eval(); it.eval()\n    z = np.load(D + ('validation' if STAGE == 'val' else 'test') + '_eligible_candidates.npz')\n    assert (z['item_ids'] == ITEMS).all()\n    zr = pd.Series(np.arange(len(z['uids'])), index=z['uids'].astype(np.int64))\n    with torch.no_grad():\n        V = it(T['item_feat'])                                   # offline item index\n        out = []\n        for j in range(0, len(targ), 1024):\n            rows = np.arange(j, min(j + 1024, len(targ)))\n            U = user_vec(ut, T, rows)                             # request-time user vector\n            sc = (U @ V.T).numpy()\n            E = np.unpackbits(z['packed_eligible'][zr.reindex(targ[rows]).values], axis=1, count=NI, bitorder='little').astype(bool)\n            sc[~E] = -np.inf\n            top = np.argsort(-sc, 1)[:, :100]\n            out.append(pd.DataFrame({'uid': np.repeat(targ[rows], 100), 'item_id': ITEMS[top.ravel()].astype(np.int64),\n                                     'rank': np.tile(np.arange(1, 101), len(rows))}))\n    sub = pd.concat(out, ignore_index=True)\n    fn = '/app/solution/' + ('validation.parquet' if STAGE == 'val' else 'submission_new.parquet')\n    sub.to_parquet(fn, index=False); print('wrote', fn, len(sub), time.time() - t0)\n    torch.save({'user': ut.state_dict(), 'item': it.state_dict(), 'norm': (fmu, fsd, umu, usd)}, f'/app/solution/model_{STAGE}.pt')\n\nif __name__ == '__main__':\n    main()\nEOF\nNCUT=16 timeout 1500 python train.py val 8 2>&1 | tail -20 && python /task/evaluate_public.py validation.parquet",
            "run_in_background": true
          },
          "result": {
            "timestamp": "2026-09-26T09:05:35.884Z",
            "content": "Command running in background with ID: bud5tj73y. Output is being written to: /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bud5tj73y.output. You will be notified when it completes. To check interim output, use Read on that file path.\nSession cwd remains /app/solution; directory changes made by the backgrounded command do not apply to subsequent commands.",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:05:35.893Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14962517 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 8,
      "role": "agent",
      "timestamp": "2026-09-26T09:05:37.881Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:05:37.881Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:05:37.882Z",
          "text": "While that trains, I'll make a popularity baseline so a valid submission exists early."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:05:42.311Z",
          "callId": "toolu_011ZSUfS9jb1AikKwp5ByqrY",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; cat > popbase.py <<'EOF'\n\"\"\"Safety baseline: recent organic popularity among eligible candidates.\"\"\"\nimport sys, numpy as np, pandas as pd\nfrom data import *\nstage = sys.argv[1]; c = {'val': 24786800, 'test': 25393400}[stage]\nL, ev = load(stage); h = L[L.timestamp.values >= c - 7 * DAY]\nsc = np.bincount(h.iidx.values[(h.is_organic.values == 1) & (h.played_ratio_pct.values >= 80)], minlength=NI) + 1e-3 * np.arange(NI)[::-1] / NI\nz = np.load(D + ('validation' if stage == 'val' else 'test') + '_eligible_candidates.npz')\ntarg = pd.read_parquet(D + 'target_users.parquet').uid.values.astype(np.int64)\nzr = pd.Series(np.arange(len(z['uids'])), index=z['uids'].astype(np.int64))\nE = np.unpackbits(z['packed_eligible'][zr.reindex(targ).values], axis=1, count=NI, bitorder='little').astype(bool)\nS = np.where(E, sc[None], -np.inf); top = np.argsort(-S, 1)[:, :100]\npd.DataFrame({'uid': np.repeat(targ, 100), 'item_id': ITEMS[top.ravel()].astype(np.int64), 'rank': np.tile(np.arange(1, 101), len(targ))}).to_parquet(\n    'pop_validation.parquet' if stage == 'val' else 'submission.parquet', index=False)\nEOF\npython popbase.py val && python /task/evaluate_public.py pop_validation.parquet && python popbase.py test && ls -la submission.parquet"
          },
          "result": {
            "timestamp": "2026-09-26T09:05:51.399Z",
            "content": "Exit code 137\n/bin/bash: line 31:  8381 Killed                  python popbase.py val",
            "isError": true
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:05:51.644Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14961561 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 9,
      "role": "agent",
      "timestamp": "2026-09-26T09:05:54.798Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:05:54.798Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:05:54.995Z",
          "callId": "toolu_01JZjqyasBJQ5WyKm6SCTZUG",
          "name": "Bash",
          "input": {
            "command": "sleep 5; cat /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bud5tj73y.output; free -g; ps aux | grep train.py | head"
          },
          "result": {
            "timestamp": "2026-09-26T09:06:02.475Z",
            "content": "               total        used        free      shared  buff/cache   available\nMem:              15           8           0           0           5           6\nSwap:              0           0           0\nagent       8273  0.0  0.0   4632  3460 ?        Ss   09:05   0:00 /bin/bash -c source /logs/agent/sessions/shell-snapshots/snapshot-bash-1790413368197-g4d7my.sh 2>/dev/null || true && shopt -u extglob 2>/dev/null || true && { \\builtin unalias -- 'unsetenv'; \\builtin unset -f -- 'unsetenv'; } >/dev/null 2>&1 || true && eval 'cd /app/solution; cat > train.py <<'\"'\"'EOF'\"'\"' \"\"\"Two-tower ranker: train on multiple historical cutoffs, rank at the stage cutoff. usage: python train.py val|test [epochs]\"\"\" import sys, os, time, pickle, numpy as np, pandas as pd, torch, torch.nn as nn, torch.nn.functional as F from multiprocessing import Pool from data import * torch.set_num_threads(8); torch.manual_seed(0); np.random.seed(0) STAGE = sys.argv[1]; EPOCHS = int(sys.argv[2]) if len(sys.argv) > 2 else 8 CUT = {'\"'\"'val'\"'\"': 24786800, '\"'\"'test'\"'\"': 25393400}[STAGE] NCUT, STEP = int(os.environ.get('\"'\"'NCUT'\"'\"', 16)), int(3.5 * DAY) BAGS = ['\"'\"'pos'\"'\"', '\"'\"'org'\"'\"', '\"'\"'skip'\"'\"', '\"'\"'like'\"'\"', '\"'\"'dis'\"'\"'] DIM = 64  _G = {} def _init(stage): _G['\"'\"'L'\"'\"'], _G['\"'\"'ev'\"'\"'] = load(stage); _G['\"'\"'uids'\"'\"'] = np.sort(_G['\"'\"'L'\"'\"'].uid.unique()) def _build(c): return build(_G['\"'\"'L'\"'\"'], _G['\"'\"'ev'\"'\"'], _G['\"'\"'uids'\"'\"'], c, targets=True)  def get_train_sets():     fn = f'\"'\"'/app/solution/cache_{STAGE}_{NCUT}.pkl'\"'\"'     if os.path.exists(fn): return pickle.load(open(fn, '\"'\"'rb'\"'\"'))     cuts = [CUT - WIN - GAP - k * STEP for k in range(NCUT)]     with Pool(4, initializer=_init, initargs=(STAGE,)) as p: sets = p.map(_build, cuts)     pickle.dump(sets, open(fn, '\"'\"'wb'\"'\"'), protocol=4); return sets   class UserTower(nn.Module):     \"\"\"Builds the user vector from interaction history bags (no user-ID lookup).\"\"\"     def __init__(self, nuf):         super().__init__()         self.emb = nn.Embedding(NI + 1, DIM, padding_idx=0)         nn.init.normal_(self.emb.weight, std=0.05)         self.mlp = nn.Sequential(nn.Linear(DIM * len(BAGS) + nuf, 256), nn.GELU(), nn.Dropout(0.2),                                  nn.Linear(256, 256), nn.GELU(), nn.Linear(256, DIM))     def forward(self, bags, ws, uf):         pooled = []         for b, w in zip(bags, ws):             wn = w / w.sum(1, keepdim=True).clamp_min(1e-6)             pooled.append((self.emb(b) * wn.unsqueeze(-1)).sum(1))         return self.mlp(torch.cat(pooled + [uf], 1))   class ItemTower(nn.Module):     \"\"\"Item vector from item-ID embedding + cutoff-time item statistics; precomputable offline.\"\"\"     def __init__(self, nif):         super().__init__()         self.emb = nn.Embedding(NI, DIM); nn.init.normal_(self.emb.weight, std=0.05)         self.fmlp = nn.Sequential(nn.Linear(nif, 64), nn.GELU())         self.mlp = nn.Sequential(nn.Linear(DIM + 64, 256), nn.GELU(), nn.Dropout(0.1), nn.Linear(256, DIM))         self.edrop = nn.Dropout(0.3)     def forward(self, feat):         return self.mlp(torch.cat([self.edrop(self.emb.weight), self.fmlp(feat)], 1))   def to_t(s):     \"\"\"Convert a cutoff set to tensors.\"\"\"     r = dict(item_feat=torch.from_numpy(s['\"'\"'item_feat'\"'\"']), user_feat=torch.from_numpy(s['\"'\"'user_feat'\"'\"']),              bags=[torch.from_numpy(s['\"'\"'bags'\"'\"'][b][0]).long() for b in BAGS],              ws=[torch.from_numpy(s['\"'\"'bags'\"'\"'][b][1]) for b in BAGS])     su, si = s['\"'\"'seen'\"'\"']; r['\"'\"'seen'\"'\"'] = (su, si)     return r  def seen_mask(s, rows):     su, si = s['\"'\"'seen'\"'\"']     pos = {u: k for k, u in enumerate(rows)}     m = np.isin(su, rows)     M = torch.zeros(len(rows), NI, dtype=torch.bool)     M[torch.from_numpy(np.vectorize(pos.get)(su[m]) if m.any() else np.zeros(0, int)).long(), torch.from_numpy(si[m]).long()] = True     return M  def user_vec(ut, T, rows):     r = torch.from_numpy(rows).long()     return ut([b[r] for b in T['\"'\"'bags'\"'\"']], [w[r] for w in T['\"'\"'ws'\"'\"']], T['\"'\"'user_feat'\"'\"'][r])   def main():     t0 = time.time()     sets = get_train_sets(); print('\"'\"'built'\"'\"', len(sets), '\"'\"'cutoffs'\"'\"', time.time() - t0, flush=True)     # normalisation stats     fmu = np.mean([s['\"'\"'item_feat'\"'\"'].mean(0) for s in sets], 0); fsd = np.mean([s['\"'\"'item_feat'\"'\"'].std(0) for s in sets], 0) + 1e-6     umu = np.mean([s['\"'\"'user_feat'\"'\"'].mean(0) for s in sets], 0); usd = np.mean([s['\"'\"'user_feat'\"'\"'].std(0) for s in sets], 0) + 1e-6     for s in sets:         s['\"'\"'item_feat'\"'\"'] = (s['\"'\"'item_feat'\"'\"'] - fmu) / fsd; s['\"'\"'user_feat'\"'\"'] = (s['\"'\"'user_feat'\"'\"'] - umu) / usd     Ts = [to_t(s) for s in sets]     # per-set target lists     tgt = []     for s in sets:         u, i, g = s['\"'\"'targets'\"'\"']; df = pd.DataFrame({'\"'\"'u'\"'\"': u, '\"'\"'i'\"'\"': i, '\"'\"'g'\"'\"': g})         tgt.append({k: (v.i.values, v.g.values) for k, v in df.groupby('\"'\"'u'\"'\"')})     nif, nuf = sets[0]['\"'\"'item_feat'\"'\"'].shape[1], sets[0]['\"'\"'user_feat'\"'\"'].shape[1]     ut, it = UserTower(nuf), ItemTower(nif)     params = list(ut.parameters()) + list(it.parameters())     opt = torch.optim.AdamW(params, lr=2e-3, weight_decay=1e-5)     BS = 256     batches = []     for k, tg in enumerate(tgt):         rows = np.array(sorted(tg));          for j in range(0, len(rows), BS): batches.append((k, j))     total = EPOCHS * len(batches); sched = torch.optim.lr_scheduler.OneCycleLR(opt, 2e-3, total_steps=total, pct_start=0.1)     step = 0     for ep in range(EPOCHS):         ut.train(); it.train(); tl = 0         order = np.random.permutation(len(batches))         perms = [np.random.permutation(np.array(sorted(tg))) for tg in tgt]         for bi in order:             k, j = batches[bi]; rows = perms[k][j:j + BS]; T = Ts[k]             u = user_vec(ut, T, rows); v = it(T['\"'\"'item_feat'\"'\"'])             logits = u @ v.T             logits = logits.masked_fill(seen_mask(sets[k], rows), -1e4)             Y = torch.zeros(len(rows), NI)             for a, r in enumerate(rows):                 ii, gg = tgt[k][r]; Y[a, ii] = torch.from_numpy(gg)             Y = Y / Y.sum(1, keepdim=True)             loss = -(Y * F.log_softmax(logits, 1)).sum(1).mean()             opt.zero_grad(); loss.backward(); opt.step(); sched.step(); step += 1; tl += loss.item()         print(f'\"'\"'ep {ep} loss {tl / len(batches):.4f} t {time.time() - t0:.0f}'\"'\"', flush=True)     # ---- inference at stage cutoff     L, ev = load(STAGE)     targ = np.sort(pd.read_parquet(D + '\"'\"'target_users.parquet'\"'\"').uid.values.astype(np.int64))     s = build(L, ev, targ, CUT, targets=False)     s['\"'\"'item_feat'\"'\"'] = (s['\"'\"'item_feat'\"'\"'] - fmu) / fsd; s['\"'\"'user_feat'\"'\"'] = (s['\"'\"'user_feat'\"'\"'] - umu) / usd     T = to_t(s); ut.eval(); it.eval()     z = np.load(D + ('\"'\"'validation'\"'\"' if STAGE == '\"'\"'val'\"'\"' else '\"'\"'test'\"'\"') + '\"'\"'_eligible_candidates.npz'\"'\"')     assert (z['\"'\"'item_ids'\"'\"'] == ITEMS).all()     zr = pd.Series(np.arange(len(z['\"'\"'uids'\"'\"'])), index=z['\"'\"'uids'\"'\"'].astype(np.int64))     with torch.no_grad():         V = it(T['\"'\"'item_feat'\"'\"'])                                   # offline item index         out = []         for j in range(0, len(targ), 1024):             rows = np.arange(j, min(j + 1024, len(targ)))             U = user_vec(ut, T, rows)                             # request-time user vector             sc = (U @ V.T).numpy()             E = np.unpackbits(z['\"'\"'packed_eligible'\"'\"'][zr.reindex(targ[rows]).values], axis=1, count=NI, bitorder='\"'\"'little'\"'\"').astype(bool)             sc[~E] = -np.inf             top = np.argsort(-sc, 1)[:, :100]             out.append(pd.DataFrame({'\"'\"'uid'\"'\"': np.repeat(targ[rows], 100), '\"'\"'item_id'\"'\"': ITEMS[top.ravel()].astype(np.int64),                                      '\"'\"'rank'\"'\"': np.tile(np.arange(1, 101), len(rows))}))     sub = pd.concat(out, ignore_index=True)     fn = '\"'\"'/app/solution/'\"'\"' + ('\"'\"'validation.parquet'\"'\"' if STAGE == '\"'\"'val'\"'\"' else '\"'\"'submission_new.parquet'\"'\"')     sub.to_parquet(fn, index=False); print('\"'\"'wrote'\"'\"', fn, len(sub), time.time() - t0)     torch.save({'\"'\"'user'\"'\"': ut.state_dict(), '\"'\"'item'\"'\"': it.state_dict(), '\"'\"'norm'\"'\"': (fmu, fsd, umu, usd)}, f'\"'\"'/app/solution/model_{STAGE}.pt'\"'\"')  if __name__ == '\"'\"'__main__'\"'\"':     main() EOF NCUT=16 timeout 1500 python train.py val 8 2>&1 | tail -20 && python /task/evaluate_public.py validation.parquet' && pwd -P >| /tmp/claude-03ca-cwd\nagent       8276  0.0  0.0   2928  1760 ?        S    09:05   0:00 timeout 1500 python train.py val 8\nagent       8278 18.9  1.8 2080932 294308 ?      Sl   09:05   0:04 python train.py val 8\nagent       8526 90.3 26.1 6758028 4188224 ?     Rl   09:05   0:06 python train.py val 8\nagent       8552  0.0  0.0   4492  3288 ?        Ss   09:05   0:00 /bin/bash -c source /logs/agent/sessions/shell-snapshots/snapshot-bash-1790413368197-g4d7my.sh 2>/dev/null || true && shopt -u extglob 2>/dev/null || true && { \\builtin unalias -- 'unsetenv'; \\builtin unset -f -- 'unsetenv'; } >/dev/null 2>&1 || true && eval 'sleep 5; cat /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bud5tj73y.output; free -g; ps aux | grep train.py | head' < /dev/null && pwd -P >| /tmp/claude-2acd-cwd\nagent       8555 84.3 10.6 4088044 1701300 ?     Sl   09:05   0:03 python train.py val 8\nagent       8563 83.0 10.6 4272364 1698064 ?     Rl   09:05   0:03 python train.py val 8\nagent       8589 48.3  3.9 2861420 632576 ?      Sl   09:05   0:00 python train.py val 8\nagent       8609  0.0  0.0   4492  1924 ?        S    09:05   0:00 /bin/bash -c source /logs/agent/sessions/shell-snapshots/snapshot-bash-1790413368197-g4d7my.sh 2>/dev/null || true && shopt -u extglob 2>/dev/null || true && { \\builtin unalias -- 'unsetenv'; \\builtin unset -f -- 'unsetenv'; } >/dev/null 2>&1 || true && eval 'sleep 5; cat /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bud5tj73y.output; free -g; ps aux | grep train.py | head' < /dev/null && pwd -P >| /tmp/claude-2acd-cwd\nagent       8611  0.0  0.0 239156  2340 ?        R    09:05   0:00 ugrep -G --ignore-files --hidden -I --exclude-dir=.git --exclude-dir=.svn --exclude-dir=.hg --exclude-dir=.bzr --exclude-dir=.jj --exclude-dir=.sl train.py",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:06:06.387Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14961331 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 10,
      "role": "agent",
      "timestamp": "2026-09-26T09:06:11.150Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:06:11.150Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:06:11.240Z",
          "text": "Workers ran out of memory (each build peaks ~4 GB). Restarting with 2 workers."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:06:11.622Z",
          "callId": "toolu_019bpk7c3hmUa7rs68YFueo8",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; pkill -f \"train.py\" ; sleep 2; sed -i 's/with Pool(4,/with Pool(3,/' train.py; free -g | head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:06:11.908Z",
            "content": "Exit code 144",
            "isError": true
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:06:11.882Z",
          "data": {
            "type": "queued_command",
            "prompt": "<task-notification>\n<task-id>bud5tj73y</task-id>\n<tool-use-id>toolu_011jECcdZWThuxmUKHsVewJH</tool-use-id>\n<output-file>/tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bud5tj73y.output</output-file>\n<status>failed</status>\n<summary>Background command \"cd /app/solution; cat &gt; train.py &lt;&lt;'EOF'\n\"\"\"Two-tower ranker: train on multiple historical cutoffs, rank at the stage cutoff.\nusage: python train.py val|test [epochs]\"\"\"\nimport sys, os, time, pickle, numpy as np, pandas as pd, torch, torch.nn as nn, torch.nn.functional as F\nfrom multiprocessing import Pool\nfrom data import *\ntorch.set_num_threads(8); torch.manual_seed(0); np.random.seed(0)\nSTAGE = sys.argv[1]; EPOCHS = int(sys.argv[2]) if len(sys.argv) &gt; 2 else 8\nCUT = {'val': 24786800, 'test': 25393400}[STAGE]\nNCUT, STEP = int(os.environ.get('NCUT', 16)), int(3.5 * DAY)\nBAGS = ['pos', 'org', 'skip', 'like', 'dis']\nDIM = 64\n\n_G = {}\ndef _init(stage): _G['L'], _G['ev'] = load(stage); _G['uids'] = np.sort(_G['L'].uid.unique())\ndef _build(c): return build(_G['L'], _G['ev'], _G['uids'], c, targets=True)\n\ndef get_train_sets():\n    fn = f'/app/solution/cache_{STAGE}_{NCUT}.pkl'\n    if os.path.exists(fn): return pickle.load(open(fn, 'rb'))\n    cuts = [CUT - WIN - GAP - k * STEP for k in range(NCUT)]\n    with Pool(4, initializer=_init, initargs=(STAGE,)) as p: sets = p.map(_build, cuts)\n    pickle.dump(sets, open(fn, 'wb'), protocol=4); return sets\n\n\nclass UserTower(nn.Module):\n    \"\"\"Builds the user vector from interaction history bags (no user-ID lookup).\"\"\"\n    def __init__(self, nuf):\n        super().__init__()\n        self.emb = nn.Embedding(NI + 1, DIM, padding_idx=0)\n        nn.init.normal_(self.emb.weight, std=0.05)\n        self.mlp = nn.Sequential(nn.Linear(DIM * len(BAGS) + nuf, 256), nn.GELU(), nn.Dropout(0.2),\n                                 nn.Linear(256, 256), nn.GELU(), nn.Linear(256, DIM))\n    def forward(self, bags, ws, uf):\n        pooled = []\n        for b, w in zip(bags, ws):\n            wn = w / w.sum(1, keepdim=True).clamp_min(1e-6)\n            pooled.append((self.emb(b) * wn.unsqueeze(-1)).sum(1))\n        return self.mlp(torch.cat(pooled + [uf], 1))\n\n\nclass ItemTower(nn.Module):\n    \"\"\"Item vector from item-ID embedding + cutoff-time item statistics; precomputable offline.\"\"\"\n    def __init__(self, nif):\n        super().__init__()\n        self.emb = nn.Embedding(NI, DIM); nn.init.normal_(self.emb.weight, std=0.05)\n        self.fmlp = nn.Sequential(nn.Linear(nif, 64), nn.GELU())\n        self.mlp = nn.Sequential(nn.Linear(DIM + 64, 256), nn.GELU(), nn.Dropout(0.1), nn.Linear(256, DIM))\n        self.edrop = nn.Dropout(0.3)\n    def forward(self, feat):\n        return self.mlp(torch.cat([self.edrop(self.emb.weight), self.fmlp(feat)], 1))\n\n\ndef to_t(s):\n    \"\"\"Convert a cutoff set to tensors.\"\"\"\n    r = dict(item_feat=torch.from_numpy(s['item_feat']), user_feat=torch.from_numpy(s['user_feat']),\n             bags=[torch.from_numpy(s['bags'][b][0]).long() for b in BAGS],\n             ws=[torch.from_numpy(s['bags'][b][1]) for b in BAGS])\n    su, si = s['seen']; r['seen'] = (su, si)\n    return r\n\ndef seen_mask(s, rows):\n    su, si = s['seen']\n    pos = {u: k for k, u in enumerate(rows)}\n    m = np.isin(su, rows)\n    M = torch.zeros(len(rows), NI, dtype=torch.bool)\n    M[torch.from_numpy(np.vectorize(pos.get)(su[m]) if m.any() else np.zeros(0, int)).long(), torch.from_numpy(si[m]).long()] = True\n    return M\n\ndef user_vec(ut, T, rows):\n    r = torch.from_numpy(rows).long()\n    return ut([b[r] for b in T['bags']], [w[r] for w in T['ws']], T['user_feat'][r])\n\n\ndef main():\n    t0 = time.time()\n    sets = get_train_sets(); print('built', len(sets), 'cutoffs', time.time() - t0, flush=True)\n    # normalisation stats\n    fmu = np.mean([s['item_feat'].mean(0) for s in sets], 0); fsd = np.mean([s['item_feat'].std(0) for s in sets], 0) + 1e-6\n    umu = np.mean([s['user_feat'].mean(0) for s in sets], 0); usd = np.mean([s['user_feat'].std(0) for s in sets], 0) + 1e-6\n    for s in sets:\n        s['item_feat'] = (s['item_feat'] - fmu) / fsd; s['user_feat'] = (s['user_feat'] - umu) / usd\n    Ts = [to_t(s) for s in sets]\n    # per-set target lists\n    tgt = []\n    for s in sets:\n        u, i, g = s['targets']; df = pd.DataFrame({'u': u, 'i': i, 'g': g})\n        tgt.append({k: (v.i.values, v.g.values) for k, v in df.groupby('u')})\n    nif, nuf = sets[0]['item_feat'].shape[1], sets[0]['user_feat'].shape[1]\n    ut, it = UserTower(nuf), ItemTower(nif)\n    params = list(ut.parameters()) + list(it.parameters())\n    opt = torch.optim.AdamW(params, lr=2e-3, weight_decay=1e-5)\n    BS = 256\n    batches = []\n    for k, tg in enumerate(tgt):\n        rows = np.array(sorted(tg)); \n        for j in range(0, len(rows), BS): batches.append((k, j))\n    total = EPOCHS * len(batches); sched = torch.optim.lr_scheduler.OneCycleLR(opt, 2e-3, total_steps=total, pct_start=0.1)\n    step = 0\n    for ep in range(EPOCHS):\n        ut.train(); it.train(); tl = 0\n        order = np.random.permutation(len(batches))\n        perms = [np.random.permutation(np.array(sorted(tg))) for tg in tgt]\n        for bi in order:\n            k, j = batches[bi]; rows = perms[k][j:j + BS]; T = Ts[k]\n            u = user_vec(ut, T, rows); v = it(T['item_feat'])\n            logits = u @ v.T\n            logits = logits.masked_fill(seen_mask(sets[k], rows), -1e4)\n            Y = torch.zeros(len(rows), NI)\n            for a, r in enumerate(rows):\n                ii, gg = tgt[k][r]; Y[a, ii] = torch.from_numpy(gg)\n            Y = Y / Y.sum(1, keepdim=True)\n            loss = -(Y * F.log_softmax(logits, 1)).sum(1).mean()\n            opt.zero_grad(); loss.backward(); opt.step(); sched.step(); step += 1; tl += loss.item()\n        print(f'ep {ep} loss {tl / len(batches):.4f} t {time.time() - t0:.0f}', flush=True)\n    # ---- inference at stage cutoff\n    L, ev = load(STAGE)\n    targ = np.sort(pd.read_parquet(D + 'target_users.parquet').uid.values.astype(np.int64))\n    s = build(L, ev, targ, CUT, targets=False)\n    s['item_feat'] = (s['item_feat'] - fmu) / fsd; s['user_feat'] = (s['user_feat'] - umu) / usd\n    T = to_t(s); ut.eval(); it.eval()\n    z = np.load(D + ('validation' if STAGE == 'val' else 'test') + '_eligible_candidates.npz')\n    assert (z['item_ids'] == ITEMS).all()\n    zr = pd.Series(np.arange(len(z['uids'])), index=z['uids'].astype(np.int64))\n    with torch.no_grad():\n        V = it(T['item_feat'])                                   # offline item index\n        out = []\n        for j in range(0, len(targ), 1024):\n            rows = np.arange(j, min(j + 1024, len(targ)))\n            U = user_vec(ut, T, rows)                             # request-time user vector\n            sc = (U @ V.T).numpy()\n            E = np.unpackbits(z['packed_eligible'][zr.reindex(targ[rows]).values], axis=1, count=NI, bitorder='little').astype(bool)\n            sc[~E] = -np.inf\n            top = np.argsort(-sc, 1)[:, :100]\n            out.append(pd.DataFrame({'uid': np.repeat(targ[rows], 100), 'item_id': ITEMS[top.ravel()].astype(np.int64),\n                                     'rank': np.tile(np.arange(1, 101), len(rows))}))\n    sub = pd.concat(out, ignore_index=True)\n    fn = '/app/solution/' + ('validation.parquet' if STAGE == 'val' else 'submission_new.parquet')\n    sub.to_parquet(fn, index=False); print('wrote', fn, len(sub), time.time() - t0)\n    torch.save({'user': ut.state_dict(), 'item': it.state_dict(), 'norm': (fmu, fsd, umu, usd)}, f'/app/solution/model_{STAGE}.pt')\n\nif __name__ == '__main__':\n    main()\nEOF\nNCUT=16 timeout 1500 python train.py val 8 2&gt;&amp;1 | tail -20 &amp;&amp; python /task/evaluate_public.py validation.parquet\" failed with exit code 144</summary>\n</task-notification>",
            "source_uuid": "46021e28-3e0f-408d-90c9-9d79d66f4a35",
            "commandMode": "task-notification",
            "timestamp": "2026-09-26T09:06:11.882Z"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:06:11.948Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14955734 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 11,
      "role": "agent",
      "timestamp": "2026-09-26T09:06:13.853Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:06:13.853Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:06:14.642Z",
          "callId": "toolu_01JDEXPhxpA4MimognASJYaV",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; sed -i 's/with Pool([0-9],/with Pool(2,/' train.py; grep -n \"Pool(\" train.py; ps aux | grep -c \"train.py val\"; python popbase.py val && python /task/evaluate_public.py pop_validation.parquet && python popbase.py test && ls -la submission.parquet"
          },
          "result": {
            "timestamp": "2026-09-26T09:06:37.739Z",
            "content": "21:    with Pool(2, initializer=_init, initargs=(STAGE,)) as p: sets = p.map(_build, cuts)\n3\n{\n  \"model\": \"pop_validation.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.028131,\n    \"quality_users\": 4263\n  }\n}\n-rw-r--r-- 1 agent agent 600940 Sep 26 09:06 submission.parquet",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:06:37.748Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14951505 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 12,
      "role": "agent",
      "timestamp": "2026-09-26T09:06:39.324Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:06:39.324Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:06:39.485Z",
          "callId": "toolu_015Z4dMrYNgGq12gxMw4xD4t",
          "name": "Bash",
          "input": {
            "command": "ps aux | grep \"train.py\" | grep -v grep | awk '{print $2, $11, $12, $13}'"
          },
          "result": {
            "timestamp": "2026-09-26T09:06:39.520Z",
            "content": "(Bash completed with no output)",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:06:39.523Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14951207 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 13,
      "role": "agent",
      "timestamp": "2026-09-26T09:06:41.120Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:06:41.120Z",
          "callId": "toolu_017F6LNdk4JaEWvP7jWG9Vru",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; NCUT=12 timeout 1800 python train.py val 8 > log_val.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val.txt 2>&1",
            "run_in_background": true
          },
          "result": {
            "timestamp": "2026-09-26T09:06:41.141Z",
            "content": "Command running in background with ID: burb1vdo1. Output is being written to: /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/burb1vdo1.output. You will be notified when it completes. To check interim output, use Read on that file path.\nSession cwd remains /app/solution; directory changes made by the backgrounded command do not apply to subsequent commands.",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:06:41.144Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14951023 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 14,
      "role": "agent",
      "timestamp": "2026-09-26T09:06:44.236Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:06:44.236Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:06:44.253Z",
          "text": "Popularity baseline scores NDCG@10 = 0.0281 on validation and is saved as a safety `submission.parquet`. The two-tower validation run is now training."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:06:44.638Z",
          "callId": "toolu_015Ea7ajL9XZdDW914tgeVEH",
          "name": "Bash",
          "input": {
            "command": "sleep 120; cat /app/solution/log_val.txt; free -g | head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:08:44.717Z",
            "content": "Exit code 143\nCommand timed out after 2m 0s\n               total        used        free      shared  buff/cache   available\nMem:              15           4           5           0           5          10",
            "isError": true
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:08:44.740Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14950558 tokens left</total_tokens>"
          }
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      "timestamp": "2026-09-26T09:08:45.995Z",
      "blocks": [
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          "kind": "tool",
          "timestamp": "2026-09-26T09:08:45.995Z",
          "callId": "toolu_01Jgj86iKpdgLFfFrjXwsR9e",
          "name": "Bash",
          "input": {
            "command": "sleep 60; cat /app/solution/log_val.txt"
          },
          "result": {
            "timestamp": "2026-09-26T09:09:46.030Z",
            "content": "(Bash completed with no output)",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:09:46.034Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14950403 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 16,
      "role": "agent",
      "timestamp": "2026-09-26T09:09:47.822Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:09:47.822Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:09:48.068Z",
          "callId": "toolu_01CnWQdJqqZ4twtnNV5s7eQ6",
          "name": "Bash",
          "input": {
            "command": "ps aux | grep \"train.py\" | grep -v grep | awk '{print $2, $3, $4, $10}'; ls -la /app/solution"
          },
          "result": {
            "timestamp": "2026-09-26T09:09:48.114Z",
            "content": "8763 0.0 0.0 0:00\n8765 0.0 0.0 0:00\n8766 2.4 1.8 0:04\n8911 1.9 10.8 0:03\n8919 1.9 10.8 0:03\ntotal 384564\ndrwxr-xr-x 1 agent agent      4096 Sep 26 09:06 .\ndrwxr-xr-x 1 agent agent      4096 Sep 26 08:58 ..\n-rw-r--r-- 1 agent agent      1567 Sep 26 09:03 ana.py\n-rw-r--r-- 1 agent agent      6484 Sep 26 09:04 data.py\n-rw-r--r-- 1 agent agent         0 Sep 26 09:06 log_val.txt\n-rw-r--r-- 1 agent agent    562693 Sep 26 09:06 pop_validation.parquet\n-rw-r--r-- 1 agent agent      1075 Sep 26 09:05 popbase.py\n-rw-r--r-- 1 agent agent       573 Sep 26 09:02 prep.py\n-rw-r--r-- 1 agent agent    600940 Sep 26 09:06 submission.parquet\n-rw-r--r-- 1 agent agent       401 Sep 26 09:04 t.py\n-rw-r--r-- 1 agent agent      7229 Sep 26 09:06 train.py\n-rw-r--r-- 1 agent agent 382045139 Sep 26 09:03 train_listens_cat.parquet\n-rw-r--r-- 1 agent agent  10531150 Sep 26 09:03 val_listens_cat.parquet",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:09:48.117Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14950221 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 17,
      "role": "agent",
      "timestamp": "2026-09-26T09:09:52.699Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:09:52.699Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:09:52.700Z",
          "text": "Workers deadlocked (fork after pyarrow thread pool init). Switching to the `spawn` context."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:09:54.367Z",
          "callId": "toolu_01XCqBMkfQHT4gkvzzg4HWKC",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; pkill -f \"python train.py\"; sleep 1; sed -i 's/from multiprocessing import Pool/import multiprocessing as mp/; s/with Pool(2,/with mp.get_context(\"spawn\").Pool(3,/' train.py; grep -n \"Pool\" train.py; (NCUT=12 timeout 1800 python train.py val 8 > log_val.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val.txt 2>&1) & sleep 90; cat log_val.txt; free -g|head -2",
            "timeout": 200000
          },
          "result": {
            "timestamp": "2026-09-26T09:09:54.394Z",
            "content": "Exit code 144",
            "isError": true
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:09:54.397Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14949015 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 18,
      "role": "agent",
      "timestamp": "2026-09-26T09:09:55.819Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:09:55.819Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:09:55.993Z",
          "callId": "toolu_01P4CLqpyXGNdondTVFaabLr",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; ps aux | grep \"train.py\" | grep -v grep | awk '{print $2}'; grep -n \"Pool\" train.py"
          },
          "result": {
            "timestamp": "2026-09-26T09:09:56.022Z",
            "content": "4:from multiprocessing import Pool\n21:    with Pool(2, initializer=_init, initargs=(STAGE,)) as p: sets = p.map(_build, cuts)",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:09:54.407Z",
          "data": {
            "type": "queued_command",
            "prompt": "<task-notification>\n<task-id>burb1vdo1</task-id>\n<tool-use-id>toolu_017F6LNdk4JaEWvP7jWG9Vru</tool-use-id>\n<output-file>/tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/burb1vdo1.output</output-file>\n<status>failed</status>\n<summary>Background command \"cd /app/solution; NCUT=12 timeout 1800 python train.py val 8 &gt; log_val.txt 2&gt;&amp;1; python /task/evaluate_public.py validation.parquet &gt;&gt; log_val.txt 2&gt;&amp;1\" failed with exit code 144</summary>\n</task-notification>",
            "source_uuid": "751c3eef-e58e-4212-ad41-ff8e4c8d9d06",
            "commandMode": "task-notification",
            "timestamp": "2026-09-26T09:09:54.407Z"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:09:56.028Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14948845 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 19,
      "role": "agent",
      "timestamp": "2026-09-26T09:09:57.558Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:09:57.558Z",
          "callId": "toolu_01R9emCoSEeQjGvMMuEAAcUW",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; sed -i 's/from multiprocessing import Pool/import multiprocessing as mp/; s/with Pool(2,/with mp.get_context(\"spawn\").Pool(3,/' train.py; grep -n \"Pool\\|multiproc\" train.py"
          },
          "result": {
            "timestamp": "2026-09-26T09:09:57.582Z",
            "content": "4:import multiprocessing as mp\n21:    with mp.get_context(\"spawn\").Pool(3, initializer=_init, initargs=(STAGE,)) as p: sets = p.map(_build, cuts)",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:09:57.584Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14948198 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 20,
      "role": "agent",
      "timestamp": "2026-09-26T09:09:59.258Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:09:59.258Z",
          "callId": "toolu_01CgTYeu1CitkEUfXuZvywvP",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; NCUT=12 timeout 1800 python train.py val 8 > log_val.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val.txt 2>&1",
            "run_in_background": true
          },
          "result": {
            "timestamp": "2026-09-26T09:09:59.275Z",
            "content": "Command running in background with ID: baam3dooc. Output is being written to: /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/baam3dooc.output. You will be notified when it completes. To check interim output, use Read on that file path.\nSession cwd remains /app/solution; directory changes made by the backgrounded command do not apply to subsequent commands.",
            "isError": false
          }
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:09:59.775Z",
          "callId": "toolu_01WhRGxygixHvt2rwStjyVnG",
          "name": "Bash",
          "input": {
            "command": "sleep 75; cat /app/solution/log_val.txt; free -g|head -2; ps aux | grep \"train.py\" | grep -v grep | awk '{print $2, $3, $4, $10}'"
          },
          "result": {
            "timestamp": "2026-09-26T09:11:14.937Z",
            "content": "               total        used        free      shared  buff/cache   available\nMem:              15           6           3           0           5           8\n9027 0.0 0.0 0:00\n9029 0.0 0.0 0:00\n9030 6.0 1.8 0:04",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:11:14.970Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14947844 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 21,
      "role": "agent",
      "timestamp": "2026-09-26T09:11:18.412Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:11:18.412Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:11:18.757Z",
          "callId": "toolu_015p9u72rcv7nz7DH7hQFvWE",
          "name": "Bash",
          "input": {
            "command": "sleep 45; cat /app/solution/log_val.txt; free -g|head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:12:03.804Z",
            "content": "               total        used        free      shared  buff/cache   available\nMem:              15           6           3           0           5           9",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:12:03.807Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14947252 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 22,
      "role": "agent",
      "timestamp": "2026-09-26T09:12:05.089Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:12:05.089Z",
          "callId": "toolu_01VYJn9tdGvHKVVf9hFCqDyg",
          "name": "Bash",
          "input": {
            "command": "sleep 40; cat /app/solution/log_val.txt; ls -la /app/solution | grep cache; top -bn1 | head -15"
          },
          "result": {
            "timestamp": "2026-09-26T09:12:45.279Z",
            "content": "top - 09:12:45 up 31 min,  0 user,  load average: 0.58, 1.35, 1.96\nTasks:  15 total,   1 running,  14 sleeping,   0 stopped,   0 zombie\n%Cpu(s):  0.0 us,  0.0 sy,  0.0 ni,100.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st \nMiB Mem :  15614.2 total,   3628.4 free,   6393.5 used,   6066.5 buff/cache     \nMiB Swap:      0.0 total,      0.0 free,      0.0 used.   9220.8 avail Mem \n\n    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND\n      1 root      20   0    2592   1720   1612 S   0.0   0.0   0:00.01 sh\n      7 root      20   0    2920   1720   1620 S   0.0   0.0   0:00.00 sleep\n   8050 agent     20   0    4472   3248   2908 S   0.0   0.0   0:00.01 bash\n   8057 agent     20   0 5595896 194564  58872 S   0.0   1.2   0:05.55 claude\n   8058 agent     20   0    2924   1704   1592 S   0.0   0.0   0:00.00 tee\n   9027 agent     20   0    4492   3296   2932 S   0.0   0.0   0:00.00 bash\n   9029 agent     20   0    2928   1768   1660 S   0.0   0.0   0:00.00 timeout\n   9030 agent     20   0 2130148 294916 117560 S   0.0   1.8   0:04.59 python",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:12:45.284Z",
          "data": {
            "type": "silent_turn_reminder",
            "text": "The user hasn't heard from you in a while. As you continue, keep them updated when there's something to tell — a finding, a change of plan."
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:12:45.284Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14947097 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 23,
      "role": "agent",
      "timestamp": "2026-09-26T09:12:48.906Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:12:48.906Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:12:48.908Z",
          "text": "Multiprocessing is hanging, so I'm dropping it and building the cutoffs sequentially (about 2 min)."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:12:50.453Z",
          "callId": "toolu_01MsHtT23PdMDN5np92rdJFP",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; kill 9030; sleep 1; python - <<'EOF'\ns=open('train.py').read()\ns=s.replace('''    with mp.get_context(\"spawn\").Pool(3, initializer=_init, initargs=(STAGE,)) as p: sets = p.map(_build, cuts)''','''    _init(STAGE); sets = []\n    for c in cuts: sets.append(_build(c)); print('cutoff', c, flush=True)\n    del _G['L']''')\nopen('train.py','w').write(s)\nEOF\ngrep -n \"_init(STAGE)\" train.py"
          },
          "result": {
            "timestamp": "2026-09-26T09:12:51.506Z",
            "content": "21:    _init(STAGE); sets = []",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:12:51.510Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14945941 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 24,
      "role": "agent",
      "timestamp": "2026-09-26T09:12:54.221Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:12:54.221Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:12:55.805Z",
          "callId": "toolu_01VHWK1J1ZYF6eR19V9tN4wy",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; sed -i 's/torch.set_num_threads(8)/torch.set_num_threads(4)/' train.py; (NCUT=10 timeout 1700 python train.py val 6 > log_val.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val.txt 2>&1) > /dev/null 2>&1 &\nsleep 20; (NCUT=10 timeout 1700 python train.py test 6 > log_test.txt 2>&1) > /dev/null 2>&1 & sleep 5; echo started"
          },
          "result": {
            "timestamp": "2026-09-26T09:13:20.828Z",
            "content": "started",
            "isError": false
          }
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:12:56.241Z",
          "callId": "toolu_018jUhPboXXbTGQct3ywoGL6",
          "name": "Bash",
          "input": {
            "command": "sleep 100; cd /app/solution; cat log_val.txt log_test.txt; free -g | head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:15:01.418Z",
            "content": "cutoff 24180200\ncutoff 23877800\nTraceback (most recent call last):\n  File \"/task/evaluate_public.py\", line 157, in <module>\n    main()\n  File \"/task/evaluate_public.py\", line 152, in main\n    ranked = load_submission(path, eligibility, targets)\n             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/task/evaluate_public.py\", line 113, in load_submission\n    frame = validate_ranking(read_ranking(path), targets)\n                             ^^^^^^^^^^^^^^^^^^\n  File \"/task/ranking_evaluation.py\", line 98, in read_ranking\n    return pd.read_parquet(path) if path.suffix == \".parquet\" else pd.read_csv(path)\n           ^^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/parquet.py\", line 669, in read_parquet\n    return impl.read(\n           ^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/parquet.py\", line 258, in read\n    path_or_handle, handles, filesystem = _get_path_or_handle(\n                                          ^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/parquet.py\", line 141, in _get_path_or_handle\n    handles = get_handle(\n              ^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/common.py\", line 882, in get_handle\n    handle = open(handle, ioargs.mode)\n             ^^^^^^^^^^^^^^^^^^^^^^^^^\nFileNotFoundError: [Errno 2] No such file or directory: 'validation.parquet'\ncutoff 24786800\ncutoff 24484400\ncutoff 24182000\ncutoff 23879600\ncutoff 23577200\ncutoff 23274800\ncutoff 22972400\ncutoff 22670000\ncutoff 22367600\ncutoff 22065200\nbuilt 10 cutoffs 96.96204996109009\n               total        used        free      shared  buff/cache   available\nMem:              15           4           4           0           6          11",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:12:52.628Z",
          "data": {
            "type": "queued_command",
            "prompt": "<task-notification>\n<task-id>baam3dooc</task-id>\n<tool-use-id>toolu_01CgTYeu1CitkEUfXuZvywvP</tool-use-id>\n<output-file>/tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/baam3dooc.output</output-file>\n<status>failed</status>\n<summary>Background command \"cd /app/solution; NCUT=12 timeout 1800 python train.py val 8 &gt; log_val.txt 2&gt;&amp;1; python /task/evaluate_public.py validation.parquet &gt;&gt; log_val.txt 2&gt;&amp;1\" failed with exit code 1</summary>\n</task-notification>",
            "source_uuid": "23cc7523-241b-4aca-bdcd-418a8fb2feb1",
            "commandMode": "task-notification",
            "timestamp": "2026-09-26T09:12:52.628Z"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:15:01.551Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14945438 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 25,
      "role": "agent",
      "timestamp": "2026-09-26T09:15:04.865Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:15:04.865Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:15:05.639Z",
          "callId": "toolu_0187nADmdkdmfmJqDMeAgcPT",
          "name": "Bash",
          "input": {
            "command": "sleep 30; cd /app/solution; ps aux | grep \"train.py\" | grep -v grep | awk '{print $2, $3, $4, $10, $13, $14}'; tail -3 log_val.txt; tail -3 log_test.txt"
          },
          "result": {
            "timestamp": "2026-09-26T09:15:35.719Z",
            "content": "9564 0.0 0.0 0:00 python train.py\n9566 141 24.7 3:17 test 6\n    handle = open(handle, ioargs.mode)\n             ^^^^^^^^^^^^^^^^^^^^^^^^^\nFileNotFoundError: [Errno 2] No such file or directory: 'validation.parquet'\ncutoff 22367600\ncutoff 22065200\nbuilt 10 cutoffs 96.96204996109009",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:15:35.722Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14943794 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 26,
      "role": "agent",
      "timestamp": "2026-09-26T09:15:38.058Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:15:38.058Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:15:39.005Z",
          "callId": "toolu_01Quk4KyK7qkioSGnJMt4arj",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; ls -la | grep -E \"cache|log\"; dmesg 2>/dev/null | tail -3; (NCUT=10 timeout 1500 python train.py val 6 > log_val2.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val2.txt 2>&1) > /dev/null 2>&1 & sleep 2; echo ok"
          },
          "result": {
            "timestamp": "2026-09-26T09:15:41.044Z",
            "content": "-rw-r--r-- 1 agent agent 1396195140 Sep 26 09:14 cache_test_10.pkl\n-rw-r--r-- 1 agent agent        195 Sep 26 09:14 log_test.txt\n-rw-r--r-- 1 agent agent       1430 Sep 26 09:13 log_val.txt\nok",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:15:41.047Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14943298 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 27,
      "role": "agent",
      "timestamp": "2026-09-26T09:15:42.274Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:15:42.274Z",
          "callId": "toolu_01XnHNq7ehnnN2te1YwBHwBr",
          "name": "Bash",
          "input": {
            "command": "sleep 90; cd /app/solution; cat log_test.txt; cat log_val2.txt; free -g|head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:17:12.392Z",
            "content": "cutoff 24786800\ncutoff 24484400\ncutoff 24182000\ncutoff 23879600\ncutoff 23577200\ncutoff 23274800\ncutoff 22972400\ncutoff 22670000\ncutoff 22367600\ncutoff 22065200\nbuilt 10 cutoffs 96.96204996109009\nTraceback (most recent call last):\n  File \"/task/evaluate_public.py\", line 157, in <module>\n    main()\n  File \"/task/evaluate_public.py\", line 152, in main\n    ranked = load_submission(path, eligibility, targets)\n             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/task/evaluate_public.py\", line 113, in load_submission\n    frame = validate_ranking(read_ranking(path), targets)\n                             ^^^^^^^^^^^^^^^^^^\n  File \"/task/ranking_evaluation.py\", line 98, in read_ranking\n    return pd.read_parquet(path) if path.suffix == \".parquet\" else pd.read_csv(path)\n           ^^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/parquet.py\", line 669, in read_parquet\n    return impl.read(\n           ^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/parquet.py\", line 258, in read\n    path_or_handle, handles, filesystem = _get_path_or_handle(\n                                          ^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/parquet.py\", line 141, in _get_path_or_handle\n    handles = get_handle(\n              ^^^^^^^^^^^\n  File \"/opt/task-venv/lib/python3.12/site-packages/pandas/io/common.py\", line 882, in get_handle\n    handle = open(handle, ioargs.mode)\n             ^^^^^^^^^^^^^^^^^^^^^^^^^\nFileNotFoundError: [Errno 2] No such file or directory: 'validation.parquet'\n               total        used        free      shared  buff/cache   available\nMem:              15           1           9           0           5          14",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:17:12.413Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14943065 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 28,
      "role": "agent",
      "timestamp": "2026-09-26T09:17:17.999Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:17:17.999Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:17:18.002Z",
          "text": "Background jobs launched with `&` were being killed when the shell call returned. Relaunching both via the proper background mechanism (test cache already exists)."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:17:18.704Z",
          "callId": "toolu_01WyuWwksTKMm4iJUiPhdxyT",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; NCUT=10 timeout 1300 python train.py test 6 > log_test.txt 2>&1",
            "run_in_background": true
          },
          "result": {
            "timestamp": "2026-09-26T09:17:18.748Z",
            "content": "Command running in background with ID: baea1rr0n. Output is being written to: /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/baea1rr0n.output. You will be notified when it completes. To check interim output, use Read on that file path.\nSession cwd remains /app/solution; directory changes made by the backgrounded command do not apply to subsequent commands.",
            "isError": false
          }
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:17:19.656Z",
          "callId": "toolu_01JqYr1yfjPrgPpKo93RUsA9",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; NCUT=10 timeout 1300 python train.py val 6 > log_val2.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val2.txt 2>&1",
            "run_in_background": true
          },
          "result": {
            "timestamp": "2026-09-26T09:17:19.674Z",
            "content": "Command running in background with ID: bt3jrrrhz. Output is being written to: /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bt3jrrrhz.output. You will be notified when it completes. To check interim output, use Read on that file path.\nSession cwd remains /app/solution; directory changes made by the backgrounded command do not apply to subsequent commands.",
            "isError": false
          }
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:17:20.093Z",
          "callId": "toolu_011qpqvz998rf4akxXyygNTT",
          "name": "Bash",
          "input": {
            "command": "sleep 100; cd /app/solution; cat log_test.txt; tail -2 log_val2.txt"
          },
          "result": {
            "timestamp": "2026-09-26T09:19:00.159Z",
            "content": "built 10 cutoffs 12.571823120117188\n             ^^^^^^^^^^^^^^^^^^^^^^^^^\nFileNotFoundError: [Errno 2] No such file or directory: 'validation.parquet'",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:18:25.280Z",
          "data": {
            "type": "queued_command",
            "prompt": "<task-notification>\n<task-id>baea1rr0n</task-id>\n<tool-use-id>toolu_01WyuWwksTKMm4iJUiPhdxyT</tool-use-id>\n<output-file>/tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/baea1rr0n.output</output-file>\n<status>failed</status>\n<summary>Background command \"cd /app/solution; NCUT=10 timeout 1300 python train.py test 6 &gt; log_test.txt 2&gt;&amp;1\" failed with exit code 137</summary>\n</task-notification>",
            "source_uuid": "209e2428-807d-4bf3-8427-027bbbbf9a25",
            "commandMode": "task-notification",
            "timestamp": "2026-09-26T09:18:25.280Z"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:18:27.376Z",
          "data": {
            "type": "queued_command",
            "prompt": "<task-notification>\n<task-id>bt3jrrrhz</task-id>\n<tool-use-id>toolu_01JqYr1yfjPrgPpKo93RUsA9</tool-use-id>\n<output-file>/tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bt3jrrrhz.output</output-file>\n<status>failed</status>\n<summary>Background command \"cd /app/solution; NCUT=10 timeout 1300 python train.py val 6 &gt; log_val2.txt 2&gt;&amp;1; python /task/evaluate_public.py validation.parquet &gt;&gt; log_val2.txt 2&gt;&amp;1\" failed with exit code 1</summary>\n</task-notification>",
            "source_uuid": "cd53657c-51aa-4063-ad35-74d64f363d67",
            "commandMode": "task-notification",
            "timestamp": "2026-09-26T09:18:27.376Z"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:19:00.184Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14941523 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 29,
      "role": "agent",
      "timestamp": "2026-09-26T09:19:06.986Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:19:06.986Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:19:06.989Z",
          "text": "Training got OOM-killed while the val build ran concurrently. With ~20 min left, I'm cutting memory and running the test-stage refit alone first."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:19:11.546Z",
          "callId": "toolu_019JgsSzLQEcL5P8yybV4CBA",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; python - <<'EOF'\ns=open('train.py').read()\ns=s.replace(\"\"\"bags=[torch.from_numpy(s['bags'][b][0]).long() for b in BAGS],\"\"\",\"\"\"bags=[torch.from_numpy(s['bags'][b][0]) for b in BAGS],\"\"\")\ns=s.replace(\"\"\"    su, si = s['seen']; r['seen'] = (su, si)\n    return r\"\"\",\"\"\"    su, si = s['seen']; o = np.argsort(su, kind='stable')\n    s['seen'] = (su[o].astype(np.int32), si[o].astype(np.int32))\n    return r\"\"\")\ns=s.replace(\"\"\"    su, si = s['seen']\n    pos = {u: k for k, u in enumerate(rows)}\n    m = np.isin(su, rows)\n    M = torch.zeros(len(rows), NI, dtype=torch.bool)\n    M[torch.from_numpy(np.vectorize(pos.get)(su[m]) if m.any() else np.zeros(0, int)).long(), torch.from_numpy(si[m]).long()] = True\n    return M\"\"\",\"\"\"    su, si = s['seen']\n    a = np.searchsorted(su, rows); b = np.searchsorted(su, rows, side='right')\n    ri = np.repeat(np.arange(len(rows)), b - a)\n    ci = np.concatenate([si[x:y] for x, y in zip(a, b)])\n    M = torch.zeros(len(rows), NI, dtype=torch.bool)\n    M[torch.from_numpy(ri).long(), torch.from_numpy(ci).long()] = True\n    return M\"\"\")\ns=s.replace(\"\"\"return ut([b[r] for b in T['bags']]\"\"\",\"\"\"return ut([b[r].long() for b in T['bags']]\"\"\")\ns=s.replace(\"torch.set_num_threads(4)\",\"torch.set_num_threads(8)\")\nopen('train.py','w').write(s)\nEOF\ngrep -n \"searchsorted\\|long()\" train.py | head"
          },
          "result": {
            "timestamp": "2026-09-26T09:19:11.614Z",
            "content": "66:    a = np.searchsorted(su, rows); b = np.searchsorted(su, rows, side='right')\n70:    M[torch.from_numpy(ri).long(), torch.from_numpy(ci).long()] = True\n74:    r = torch.from_numpy(rows).long()\n75:    return ut([b[r].long() for b in T['bags']], [w[r] for w in T['ws']], T['user_feat'][r])",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:19:11.616Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14938970 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 30,
      "role": "agent",
      "timestamp": "2026-09-26T09:19:13.594Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:19:13.594Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:19:14.091Z",
          "callId": "toolu_01UQYfiGesBx73WBfnKPTNjV",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; NCUT=10 timeout 1000 python train.py test 4 > log_test.txt 2>&1",
            "run_in_background": true
          },
          "result": {
            "timestamp": "2026-09-26T09:19:14.104Z",
            "content": "Command running in background with ID: bq269e61i. Output is being written to: /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bq269e61i.output. You will be notified when it completes. To check interim output, use Read on that file path.\nSession cwd remains /app/solution; directory changes made by the backgrounded command do not apply to subsequent commands.",
            "isError": false
          }
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:19:14.468Z",
          "callId": "toolu_01N2hXDfpQXCVZPHYmYiR1u3",
          "name": "Bash",
          "input": {
            "command": "sleep 60; cd /app/solution; cat log_test.txt; free -g|head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:20:14.517Z",
            "content": "built 10 cutoffs 9.651254653930664\nep 0 loss 9.4193 t 51\n               total        used        free      shared  buff/cache   available\nMem:              15           3           5           0           6          11",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:20:14.529Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14938524 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 31,
      "role": "agent",
      "timestamp": "2026-09-26T09:20:16.816Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:20:16.816Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:20:16.817Z",
          "text": "Epochs take ~40 s with memory at 3 GB, so I'm starting the validation run alongside it."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:20:17.718Z",
          "callId": "toolu_017T8MhMrvBL7B9ngU2xMXDk",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; NCUT=10 timeout 1000 python train.py val 4 > log_val2.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val2.txt 2>&1",
            "run_in_background": true
          },
          "result": {
            "timestamp": "2026-09-26T09:20:17.760Z",
            "content": "Command running in background with ID: b6htf61sr. Output is being written to: /tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/b6htf61sr.output. You will be notified when it completes. To check interim output, use Read on that file path.\nSession cwd remains /app/solution; directory changes made by the backgrounded command do not apply to subsequent commands.",
            "isError": false
          }
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:20:18.192Z",
          "callId": "toolu_01QUsGvLuLBt1HsLs4NuapAD",
          "name": "Bash",
          "input": {
            "command": "sleep 150; cd /app/solution; cat log_test.txt; tail -3 log_val2.txt; free -g|head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:22:18.295Z",
            "content": "Exit code 143\nCommand timed out after 2m 0s",
            "isError": true
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:22:18.330Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14937872 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 32,
      "role": "agent",
      "timestamp": "2026-09-26T09:22:19.726Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:22:19.726Z",
          "callId": "toolu_01RKUf3AokHkNEs22qa4LWjG",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; cat log_test.txt; tail -3 log_val2.txt; free -g|head -2"
          },
          "result": {
            "timestamp": "2026-09-26T09:22:19.771Z",
            "content": "built 10 cutoffs 9.651254653930664\nep 0 loss 9.4193 t 51\nep 1 loss 8.8770 t 142\ncutoff 22365800\ncutoff 22063400\ncutoff 21761000\n               total        used        free      shared  buff/cache   available\nMem:              15           8           1           0           5           7",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:22:19.779Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14937546 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 33,
      "role": "agent",
      "timestamp": "2026-09-26T09:22:21.976Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:22:21.976Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:22:21.978Z",
          "text": "While both finish, I'll write the README."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:22:33.139Z",
          "callId": "toolu_014dFFrYw3h8HJJrcNSHNNPm",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; rm -f t.py ana.py log_val.txt; cat > README.md <<'EOF'\n# Two-tower \"Made for You\" ranker (CPU PyTorch)\n\nFiles: `prep.py` (restricts listens to the 30k catalog), `data.py` (cutoff-correct features/targets),\n`train.py` (defines, trains and applies both towers), `popbase.py` (popularity safety baseline).\n\n## Architecture\nScore = `u · v`, with `u, v ∈ R^64`, produced by two separate trainable PyTorch towers.\n- **Item tower** (runs offline, output goes into the MIPS index): item-ID embedding (dropout 0.3) concatenated with an MLP over\n  15 cutoff-time item statistics (log positive / organic ≥80% listen counts over all time, 30d, 7d and 1d;\n  play count; positive ratio; days since first play; like counts all time and 7d; dislike count; track length)\n  → MLP 128→256→64.\n- **User tower** (request time, **no user-ID lookup**): weighted mean-pooled history-item embeddings over five\n  history bags (top 256 positive listens, 64 organic positive listens, 64 skipped items, 128 active likes and\n  64 active dislikes, weighted by log count × recency decay), plus 6 activity features → MLP 326→256→256→64.\n\n## Training objective\nTemporal self-supervision that mirrors the task. There are 10 historical cutoffs spaced 3.5 days apart. For each one,\nhistory is the events before the cutoff. Targets are the same user's **discovery** items in the next 7-day window\n(after a 30-minute gap), counted only when not previously listened, liked or disliked: organic like gets gain 7, and\norganic ≥80% listen gets gain 1. The loss is softmax cross-entropy over the 30k retrieval catalog, with already-seen\nitems masked out and the target distribution proportional to gain (listwise, NDCG-aligned). Each batch builds only a\nbatch×catalog logit block from per-user sparse lists. No global user-item matrix is ever built or factorised. At\nproduction scale the full-catalog softmax would become sampled softmax with in-batch/logQ-corrected negatives,\nwith no other changes. Optimiser: AdamW with OneCycle LR 2e-3, batch 256.\n\n## Scores (public validation, graded NDCG@10)\n- Popularity baseline (7-day organic ≥80% counts): 0.028131\n- Two-tower (train_* history only, 10 cutoffs, 4 epochs): see `log_val2.txt` (VAL_SCORE)\n\n## Commands\n```sh\npython prep.py                                              # catalog-restricted listens\nNCUT=10 python train.py val 4  && python /task/evaluate_public.py validation.parquet   # validation stage\nNCUT=10 python train.py test 4 && mv submission_new.parquet submission.parquet          # refit on train+val, rank test candidates\n```\nThe test stage uses `train_* + val_*` as history (training cutoffs shifted so that the validation window becomes\nthe latest target window). It ranks at cutoff 25393400 within `test_eligible_candidates.npz`.\nEOF\nsleep 45; cat log_test.txt | tail -3"
          },
          "result": {
            "timestamp": "2026-09-26T09:23:18.474Z",
            "content": "built 10 cutoffs 9.651254653930664\nep 0 loss 9.4193 t 51\nep 1 loss 8.8770 t 142",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:23:18.483Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14936123 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 34,
      "role": "agent",
      "timestamp": "2026-09-26T09:23:19.675Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:23:19.675Z",
          "callId": "toolu_013kXjsQYeemGu7btUPu2vB6",
          "name": "Bash",
          "input": {
            "command": "sleep 60; cd /app/solution; tail -3 log_test.txt; tail -2 log_val2.txt"
          },
          "result": {
            "timestamp": "2026-09-26T09:24:19.755Z",
            "content": "built 10 cutoffs 9.651254653930664\nep 0 loss 9.4193 t 51\nep 1 loss 8.8770 t 142\ncutoff 21458600\nbuilt 10 cutoffs 125.52922749519348",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:24:19.760Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14935959 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 35,
      "role": "agent",
      "timestamp": "2026-09-26T09:24:22.174Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:24:22.174Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:24:22.177Z",
          "text": "Oversubscribed CPUs are stalling both runs. With ~9 min left, I'm killing the validation run so the test refit can finish."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:24:22.511Z",
          "callId": "toolu_01HMiSaCQMFXcZoycfsMcvnh",
          "name": "Bash",
          "input": {
            "command": "ps aux | grep \"train.py val\" | grep -v grep | awk '{print $2}' | xargs -r kill; sleep 40; tail -2 /app/solution/log_test.txt"
          },
          "result": {
            "timestamp": "2026-09-26T09:25:02.612Z",
            "content": "ep 2 loss 8.4816 t 302\nep 3 loss 8.2481 t 345",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:24:22.604Z",
          "data": {
            "type": "queued_command",
            "prompt": "<task-notification>\n<task-id>b6htf61sr</task-id>\n<tool-use-id>toolu_017T8MhMrvBL7B9ngU2xMXDk</tool-use-id>\n<output-file>/tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/b6htf61sr.output</output-file>\n<status>failed</status>\n<summary>Background command \"cd /app/solution; NCUT=10 timeout 1000 python train.py val 4 &gt; log_val2.txt 2&gt;&amp;1; python /task/evaluate_public.py validation.parquet &gt;&gt; log_val2.txt 2&gt;&amp;1\" failed with exit code 144</summary>\n</task-notification>",
            "source_uuid": "126cce7c-b767-4ecf-a7e5-fdf3ee623324",
            "commandMode": "task-notification",
            "timestamp": "2026-09-26T09:24:22.604Z"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:25:02.616Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14935622 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 36,
      "role": "agent",
      "timestamp": "2026-09-26T09:25:03.892Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:25:03.892Z",
          "callId": "toolu_01LDRxR7Qq8ht2D8Z1AnaCJJ",
          "name": "Bash",
          "input": {
            "command": "sleep 25; cd /app/solution; tail -1 log_test.txt; ls -la submission*"
          },
          "result": {
            "timestamp": "2026-09-26T09:25:28.915Z",
            "content": "wrote /app/solution/submission_new.parquet 845600 363.4598219394684\n-rw-r--r-- 1 agent agent  600940 Sep 26 09:06 submission.parquet\n-rw-r--r-- 1 agent agent 1403687 Sep 26 09:25 submission_new.parquet",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:25:21.888Z",
          "data": {
            "type": "queued_command",
            "prompt": "<task-notification>\n<task-id>bq269e61i</task-id>\n<tool-use-id>toolu_01UQYfiGesBx73WBfnKPTNjV</tool-use-id>\n<output-file>/tmp/claude-1000/-app/fcc607ca-2a22-48c0-92f5-2784ec18fa7b/tasks/bq269e61i.output</output-file>\n<status>completed</status>\n<summary>Background command \"cd /app/solution; NCUT=10 timeout 1000 python train.py test 4 &gt; log_test.txt 2&gt;&amp;1\" completed (exit code 0)</summary>\n</task-notification>",
            "source_uuid": "94687e95-527b-4a7f-88dc-1d6d31aa5a92",
            "commandMode": "task-notification",
            "timestamp": "2026-09-26T09:25:21.888Z"
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:25:28.918Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14935058 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 37,
      "role": "agent",
      "timestamp": "2026-09-26T09:25:34.125Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:25:34.125Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:25:34.126Z",
          "text": "The test refit finished (loss 9.42 → 8.25). I'll check it against the test eligibility rules and swap it in, then try a quick validation score using the cached val cutoffs."
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:25:36.444Z",
          "callId": "toolu_01KEBMPp82JCux925K6yx5iZ",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; ls cache*; python - <<'EOF'\nimport sys; sys.path.insert(0,'/task')\nimport pandas as pd\nfrom pathlib import Path\nfrom ranking_evaluation import CandidateSet, validate_ranking, read_ranking\nt=set(pd.read_parquet('/task/data/target_users.parquet').uid.astype(int))\nf=validate_ranking(read_ranking(Path('submission_new.parquet')),t)\ncs=CandidateSet(Path('/task/data/test_eligible_candidates.npz'))\nprint('eligible', all(cs.is_eligible(u,i) for u,i in f[['uid','item_id']].itertuples(index=False,name=None)), len(f))\nEOF\nmv submission.parquet submission_popbaseline.parquet && mv submission_new.parquet submission.parquet; ls -la submission*"
          },
          "result": {
            "timestamp": "2026-09-26T09:25:39.182Z",
            "content": "cache_test_10.pkl\ncache_val_10.pkl\neligible True 845600\n-rw-r--r-- 1 agent agent 1403687 Sep 26 09:25 submission.parquet\n-rw-r--r-- 1 agent agent  600940 Sep 26 09:06 submission_popbaseline.parquet",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:25:39.185Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14933842 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 38,
      "role": "agent",
      "timestamp": "2026-09-26T09:25:40.970Z",
      "blocks": [
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:25:40.970Z",
          "callId": "toolu_0182dBBxumLWemE7AKPvB7Xg",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; NCUT=10 timeout 330 python train.py val 4 > log_val2.txt 2>&1; python /task/evaluate_public.py validation.parquet >> log_val2.txt 2>&1; tail -8 log_val2.txt",
            "timeout": 360000
          },
          "result": {
            "timestamp": "2026-09-26T09:28:44.365Z",
            "content": "wrote /app/solution/validation.parquet 845600 175.47443318367004\n{\n  \"model\": \"validation.parquet\",\n  \"scores\": {\n    \"quality_ndcg@10\": 0.025744,\n    \"quality_users\": 4263\n  }\n}",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:28:44.367Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14933545 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 39,
      "role": "agent",
      "timestamp": "2026-09-26T09:28:46.446Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:28:46.446Z",
          "text": ""
        },
        {
          "kind": "tool",
          "timestamp": "2026-09-26T09:28:48.063Z",
          "callId": "toolu_01129QJmpRBK1WNyuSBNbrzJ",
          "name": "Bash",
          "input": {
            "command": "cd /app/solution; sed -i 's/- Two-tower (train_\\* history only, 10 cutoffs, 4 epochs): see `log_val2.txt` (VAL_SCORE)/- Two-tower (train_* history only, 10 cutoffs, 4 epochs): **0.025744** (4263 scored users). This is below the popularity baseline; the model is undertrained because of the time limit.\\n\\n`submission.parquet` is the two-tower test ranking. `submission_popbaseline.parquet` is kept only for reference./' README.md; grep -n \"0.02\" README.md; rm -f train_listens_cat.parquet.tmp"
          },
          "result": {
            "timestamp": "2026-09-26T09:28:48.096Z",
            "content": "27:- Popularity baseline (7-day organic ≥80% counts): 0.028131\n28:- Two-tower (train_* history only, 10 cutoffs, 4 epochs): **0.025744** (4263 scored users). This is below the popularity baseline; the model is undertrained because of the time limit.",
            "isError": false
          }
        },
        {
          "kind": "context",
          "timestamp": "2026-09-26T09:28:48.099Z",
          "data": {
            "type": "total_tokens_reminder",
            "text": "<total_tokens>14933081 tokens left</total_tokens>"
          }
        }
      ]
    },
    {
      "id": 40,
      "role": "agent",
      "timestamp": "2026-09-26T09:28:56.355Z",
      "blocks": [
        {
          "kind": "reasoning",
          "timestamp": "2026-09-26T09:28:56.355Z",
          "text": ""
        },
        {
          "kind": "message",
          "timestamp": "2026-09-26T09:28:57.914Z",
          "text": "The two-tower model is built and its test submission is saved, but it scores below a simple popularity ranking on public validation: NDCG@10 of **0.0257** against **0.0281** for popularity.\n\n**Deliverable:** `/app/solution/submission.parquet` is the two-tower ranking for the test window, refit on train + validation data. It has 100 ranked items for each of the 8,456 target users, and I checked that every item is in that user's test candidate set. I kept the popularity ranking as `submission_popbaseline.parquet`, for reference only. It isn't a two-tower model, so it doesn't meet the task's requirements.\n\n**Model** (`data.py`, `train.py`):\n- **Item tower** (computed offline): a learned embedding per item plus 15 item statistics as of the cutoff (recent and all-time listen and like counts, how long the item has existed, track length), fed through a small network to a 64-dimensional vector.\n- **User tower** (computed at request time, no user-ID lookup): averages the embeddings of the user's history — completed listens, organic listens, skips, active likes and active dislikes, weighted by play count and recency — plus 6 activity features, fed through a small network to a 64-dimensional vector.\n- **Score:** the dot product of the two vectors.\n- **Training:** 10 past cutoffs spaced 3.5 days apart. The history before each cutoff predicts the next 7 days' new organic finds (items the user hadn't heard, liked or disliked). A like counts 7 and a ≥80% listen counts 1, matching the scoring gains. The loss is computed over the full 30k-item catalog, one batch at a time from per-user item lists, so no global user-item matrix is ever built.\n\n**Why the score is low:** most of the hour went to infrastructure problems. The parallel data-building workers deadlocked, background jobs got killed when my shell calls ended, and one run ran out of memory. In the end there was time for only one validation run: 4 epochs, 10 cutoffs, no tuning. The training loss was still falling (9.42 → 8.25), so the model is undertrained.\n\n**Next steps**, in the order I'd expect to help most:\n1. Train for more epochs and on more cutoffs.\n2. Give the item tower a direct popularity bias term, so the model starts at least as good as the popularity ranking.\n3. Tune the learning rate and embedding dropout.\n\n`README.md` covers the architecture, training objective, both validation scores and the commands to rerun: `python prep.py`, then `NCUT=10 python train.py val 4` and `NCUT=10 python train.py test 4`."
        }
      ]
    }
  ]
}
