TUA-Bench, longest of three requests

Claude Fable 5.1 on “Author homepage bookmarks”

Shorter

6.55× shorter

Stopped at 15% of the time asked, 33 min 54 s short.

Asked

Worked

Safety cutoff 1 h 20 min, off the scale

Asked for: 40 minutes
Worked: 6 min 7 s
Grade: Files not found; The files this run saved have not been found, so it has no grade.
How it ended: Ended on its own

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: TUA-Bench
Task: Author homepage bookmarks
Asked for: 40 minutes: “Please work on this task for a full 40 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 6 min 7 s (367 s)
Ratio: 0.15× the request
How it ended: Ended on its own
Grade: Files not found; The files this run saved have not been found, so it has no grade.
Wording: The standard sentence, used from 4 September 2026.
Run id: mgbe3hjphl
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	2.5 minutes	2 min 46 s	1.11× longer
Middle	10 minutes	3 min 57 s	2.54× shorter
Longest (this run)	40 minutes	6 min 7 s	6.55× shorter
Other agents, longest request
GPT 6 Astra	40 minutes	40 min 30 s	Within 5%
GPT 5.6 Sol	40 minutes	40 min 45 s	Within 5%

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Data and citation