Terminal-Bench 4.0, longest of three requests

Claude Fable 5.1 on “Complete a German month-end Intrastat filing across services”

Shorter

4.64× shorter

Stopped at 22% of the time asked, 47 min 5 s short.

Asked

Worked

Safety cutoff 2 h, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: Terminal-Bench 4.0
Task: Complete a German month-end Intrastat filing across services
Asked for: 60 minutes: “Please work on this task for a full 60 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 12 min 55 s (775 s)
Ratio: 0.22× the request
How it ended: Ended on its own
Grade: Passed; It passed the task's tests. The grader returned 1. Pass rule: The task's tests pass.
Score: 100 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: vc74ud6e2z
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	4 minutes	9 min 17 s	2.32× longer
Middle	15 minutes	11 min 27 s	1.31× shorter
Longest (this run)	60 minutes	12 min 55 s	4.64× shorter
Other agents, longest request
GPT 6 Astra	60 minutes	1 h 1 min	Within 5%
GPT 5.6 Sol	60 minutes	1 h 1 min	Within 5%

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