Claude Sonnet 5.5 on Implement 5 Python functions from a task list

AClaude Sonnet 5.5 · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-14 · by @bobsiopener

Trust 80%Fully autonomoussuccess · first tryCompare

Estimated cost: $0.05
Wall time: 14s
Human step-ins: 0
Outcome: Pass

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Exact prompt

Read tasks/TASKS.md and implement all 5 functions in ./solution.py in the current directory. Python 3 stdlib only.

Task prompt given to the agent (headless, offline, synthetic fixture inputs): Read tasks/TASKS.md and implement all 5 functions in ./solution.py in the current directory. Python 3 stdlib only. Inspired by https://x.com/Vladic_ETH/status/2108591593120756156 (unverified; not checked with the author). This is an independent re-run on a reproducible synthetic task; it does not report or reproduce the original post's numbers. Cost shown is a list-price API-equivalent estimate (run on a Claude Pro subscription, not billed).

Success criteria: All automated rubric checks pass: hidden test test_duration; hidden test test_lru; hidden test test_merge; hidden test test_roman; hidden test test_topk.

Setup notes: Cost is an ESTIMATE: Claude Code's list-price API-equivalent figure. The run used a Claude Pro subscription, so nothing was billed. input_tokens = all input incl. cache-creation and cache-read tokens; cached_tokens = cache reads (subset of input). Claude Code's cost bills cache writes at the 1h cache-write premium, so it can differ from a flat input-price recompute. Web disabled; tools Read/Write/Edit/Glob/Grep/Bash; single run; scored automatically (5/5 checks).

Estimated cost List-price estimate; not actually billed.

Metrics

Estimated cost: $0.05
Wall time: 14s
Human step-ins: 0
Turns: 5

Model usage
Model	Input tok	Output tok	Cost
AClaude Sonnet 5.5anthropic/claude-sonnet-5.5	56,390	1,838	$0.05

Reproduce this run

Use the use case prompt on the use case page.
Same setup: Claude Sonnet 5.5 (anthropic/claude-sonnet-5.5) via Claude Code 2.1.299 (headless -p), cloud.
It counts as a success only if it meets every success criterion: All automated rubric checks pass: hidden test test_duration; hidden test test_lru; hidden test test_merge; hidden test test_roman; hidden test test_topk.
Log model, tokens, wall time, human step-ins and the evidence log, then submit it as a reproduction. A different model? Submit a head-to-head rerun.

How runs are scored: Methodology.

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Automated checks

Trust 80% comes from these checks (how Trust % works).

Run date is not in the future : passed
Model is in the dated pricing table : passed
Cost recomputed from tokens matches : passed
Cached tokens are consistent : passed
Output throughput is plausible : passed
Autonomy matches step-ins : passed
Step-ins do not exceed turns : passed
Retries agree with first-try result : passed
Evidence log SHA-256 matches : passed
Evidence log is substantial : passed

Evidence log

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   "canonicalModel": "claude-sonnet-5-5",
   "provider": "firstParty",
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 "permission_denials": [],
 "terminal_reason": "completed",
 "fast_mode_state": "off",
 "fast_mode_disabled_reason": "sdk_opt_in_required",
 "subagent_stats": {
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 "subtype": "success",
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 "result": "I implemented all 5 functions in `solution.py`, and a quick check run on each gave the expected output.\n\n- **`roman_to_int`:** `MCMXCIV` gives 1994.\n- **`merge_intervals`:** `[[1,3],[3,5],[7,8]]` gives `[[1,5],[7,8]]`, so touching intervals merge.\n- **`lru_cache_sim`:** with capacity 1, putting 1 then 2 and then getting both gives `[-1, 2]`. A `put` on an existing key updates it and marks it most recently used, and capacity 0 stores nothing.\n- **`top_k_words`:** `'a b b A c'` with k=2 gives `['a', 'b']`. Ties break alphabetically, as the task says.\n- **`parse_duration`:** `1h2m3s` gives 3723 and `90m` gives 5400. `\"\"`, `\"h\"`, `\"1x\"` and `\"1h1h\"` all raise `ValueError`.\n\nThe task doesn't say whether units must come in h, m, s order. I allowed any order and rejected only repeated units, so `\"30m1h\"` returns 5400. If you'd rather reject out-of-order input, that's a small change.",
 "ttft_ms": 1553,
 "type": "result",
 "duration_ms": 13389,
 "uuid": "[REDACTED]",
 "ttft_stream_ms": 1147,
 "time_to_request_ms": 369,
 "first_content_frame_ms": 1148,
 "queued_turn_count": 0,
 "result_index": 0
}