Sakana ALE-Bench, longest of three requests

Claude Fable 5.1 on “AtCoder Heuristic Contest 11”

Shorter

3.37× shorter

Stopped at 30% of the time asked, 2 h 21 min 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: Sakana ALE-Bench
Task: AtCoder Heuristic Contest 11
Asked for: 200 minutes: “Please work on this task for a full 200 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 59 min 17 s (3,557 s)
Ratio: 0.30× the request
How it ended: Ending not labelled yet
Grade: 2,509,695,454; 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 2631; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: bwrrte457o
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	12 min 20 s	Within 5%
Middle	50 minutes	21 min 11 s	2.36× shorter
Longest (this run)	200 minutes	59 min 17 s	3.37× shorter
Other agents, longest request
GPT 6 Astra	200 minutes	3 h 21 min	Within 5%
GPT 5.6 Sol	200 minutes	3 h 21 min	Within 5%

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Read before quoting. How this run ended has not been labelled yet. It is timed like every other run and counted in every number. Details

Data and citation