PaperBench, middle of three requests

Claude Fable 5.1 on “Bridging Data Gaps”

Shorter

3.29× shorter

Stopped at 30% of the time asked, 34 min 47 s short.

Asked

Worked

Safety cutoff 6 h 40 min, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: PaperBench
Task: Bridging Data Gaps
Asked for: 50 minutes: “Please work on this task for a full 50 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 15 min 13 s (913 s)
Ratio: 0.30× the request
How it ended: Ending not labelled yet
Grade: 0.291; Replication score: a weighted rubric of pass/fail leaf checks, 0 to 1, after a full reproduction attempt. No official pass rule.
Score: 29.1 of 100; Judged afterwards. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: r73pcqteeb
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	12.5 minutes	5 min 18 s	2.36× shorter
Middle (this run)	50 minutes	15 min 13 s	3.29× shorter
Longest	200 minutes	45 min 29 s	4.40× shorter
Other agents, middle request
GPT 6 Astra	50 minutes	50 min 38 s	Within 5%
GPT 5.6 Sol	50 minutes	51 min 15 s	Within 5%

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Data and citation