Sakana ALE-Bench, shortest of three requests

Claude Fable 5.1 on “AtCoder Heuristic Contest 39”

Shorter

1.67× shorter

Stopped at 60% of the time asked, 4 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 39
Asked for: 10 minutes: “Please work on this task for a full 10 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 6 min (360 s)
Ratio: 0.60× the request
How it ended: Ended on its own
Grade: 502,821; 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 2465; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: zvcza3ttj3
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 (this run)	10 minutes	6 min	1.67× shorter
Middle	40 minutes	13 min 25 s	2.98× shorter
Longest	150 minutes	1 h 13 min	2.06× shorter
Other agents, shortest request
GPT 6 Astra	10 minutes	10 min 21 s	Within 5%
GPT 5.6 Sol	10 minutes	12 min 25 s	1.24× longer

See it on the chart. Transcripts are not published yet.

Data and citation