Sakana ALE-Bench, middle of three requests

Claude Fable 5.1 on “AtCoder Heuristic Contest 7”

Shorter

1.43× shorter

Stopped at 70% of the time asked, 12 min short.

Asked

Worked

Safety cutoff 5 h, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: Sakana ALE-Bench
Task: AtCoder Heuristic Contest 7
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: 28 min 1 s (1,681 s)
Ratio: 0.70× the request
How it ended: Ending not labelled yet
Grade: 14,217,934,734; Raw score on the private test cases, in each problem's own units; also reports rank against human contest entrants. No official pass rule.
Score: Performance 2662; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: p754lqvx5s
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	10 minutes	10 min 4 s	Within 5%
Middle (this run)	40 minutes	28 min 1 s	1.43× shorter
Longest	150 minutes	1 h 4 min	2.36× shorter
Other agents, middle request
GPT 6 Astra	40 minutes	40 min 31 s	Within 5%
GPT 5.6 Sol	40 minutes	54 min 46 s	1.37× longer

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Data and citation