TUA-Bench, longest of three requests

Claude Fable 5.1 on “Extract gym auditorium”

Longer

1.11× longer

Worked 11% past the request, 2 min 12 s over.

Asked

Worked

Safety cutoff 40 min, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: TUA-Bench
Task: Extract gym auditorium
Asked for: 20 minutes: “Please work on this task for a full 20 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 22 min 12 s (1,332 s)
Ratio: 1.11× the request
How it ended: Ended on its own
Grade: Passed; It completed the task in full. The grader returned 1. Pass rule: Full completion: a reward of 1 on the final state.
Score: 100 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: dxgfdrgxay
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	1.25 minutes	21 min 32 s	17.23× longer
Middle	5 minutes	20 min 57 s	4.19× longer
Longest (this run)	20 minutes	22 min 12 s	1.11× longer
Other agents, longest request
GPT 6 Astra	20 minutes	20 min 27 s	Within 5%
GPT 5.6 Sol	20 minutes	21 min 32 s	1.08× longer
Muse Spark 1.3	20 minutes	8 min 15 s	2.42× shorter

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Data and citation