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

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

Trust 80%Fully autonomoussuccess · first try
Estimated cost
$0.12
Wall time
21s
Human step-ins
0
Outcome
Pass

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Summary

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
$0.12
Wall time
21s
Human step-ins
0
Turns
4
Model usage
ModelInput tokOutput tokCost
AClaude Opus 5.5anthropic/claude-opus-5.555,7962,312$0.12

Reproduce this run

  1. Use the use case prompt on the use case page.
  2. Same setup: Claude Opus 5.5 (anthropic/claude-opus-5.5) via Claude Code 2.1.299 (headless -p), cloud.
  3. 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.
  4. 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).

Evidence log
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 "result": "I created `solution.py` with all 5 functions. It didn't exist yet, and it uses only the standard library. My quick tests pass, including every example given in `TASKS.md`.\n\n1. **`roman_to_int`** converts a Roman numeral to a number (for example, `MCMXCIV` \u2192 1994 and `MMMCMXCIX` \u2192 3999). It assumes the input is a valid numeral, as the spec says, so it doesn't check for malformed ones.\n2. **`merge_intervals`** sorts the intervals and merges any that overlap or touch, so `[2,6]` and `[6,7]` become `[2,7]`.\n3. **`lru_cache_sim`** returns the result of each `get` in order, or -1 for a missing key. A capacity of 0 or less stores nothing, and an unknown operation raises `ValueError`.\n4. **`top_k_words`** lowercases the text and finds words as `[a-z']+` runs. It sorts by count, highest first, with ties in alphabetical order.\n5. **`parse_duration`** converts strings like `1h30m` to seconds and raises `ValueError` for `\"\"`, `h`, `1x` and `1h1h`. Two choices go beyond the spec:\n   - Units must appear in h, m, s order, so `30m1h` is rejected (this is also what rejects `1h1h`).\n   - A bare number like `\"90\"` with no unit is rejected.\n\n   If either of those should be accepted, I'd need to loosen the pattern.",
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 "queued_turn_count": 0,
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