TUA-Bench, shortest of three requests

Claude Fable 5.1 on “Merge text document”

Longer

2.79× longer

Worked 179% past the request, 2 min 14 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: Merge text document
Asked for: 1.25 minutes: “Please work on this task for a full 1.25 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 3 min 29 s (209 s)
Ratio: 2.79× the request
How it ended: Ended on its own
Grade: Did not pass; It did not complete the task in full. The grader returned 0.0. Pass rule: Full completion: a reward of 1 on the final state.
Score: 0 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: liuus3rc75
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 (this run)	1.25 minutes	3 min 29 s	2.79× longer
Middle	5 minutes	10 min 37 s	2.12× longer
Longest	20 minutes	9 min 53 s	2.03× shorter
Other agents, shortest request
GPT 6 Astra	1.25 minutes	1 min 48 s	1.44× longer
GPT 5.6 Sol	1.25 minutes	3 min 49 s	3.05× longer

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Data and citation