TUA-Bench, middle of three requests

Claude Fable 5.1 on “EPW parquet check”

Longer

1.56× longer

Worked 56% past the request, 3 min 23 s over.

Asked

Worked

Safety cutoff 50 min, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: TUA-Bench
Task: EPW parquet check
Asked for: 6 minutes: “Please work on this task for a full 6 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 9 min 23 s (563 s)
Ratio: 1.56× the request
How it ended: Ended on its own
Grade: Did not pass; It did not complete the task in full. The grader returned 0.66. Pass rule: Full completion: a reward of 1 on the final state.
Score: 66 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: 6kqnkdrrir
Data release: 26 Sep 2026

The other requests for Claude Fable 5.1 on this task, and the other agents at this request
Fable on this task	Asked	Worked	Result
Shortest	1.5 minutes	7 min 17 s	4.86× longer
Middle (this run)	6 minutes	9 min 23 s	1.56× longer
Longest	25 minutes	12 min 16 s	2.04× shorter
Other agents, middle request
GPT 6 Astra	6 minutes	6 min 23 s	1.06× longer
GPT 5.6 Sol	6 minutes	6 min 52 s	1.15× longer
Muse Spark 1.3	6 minutes	5 min 48 s	Within 5%

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Data and citation