Sakana ALE-Bench, shortest of three requests

Claude Fable 5.1 on “AtCoder Heuristic Contest 8”

Shorter

2.00× shorter

Stopped at 50% of the time asked, 7 min 30 s short.

Asked

Worked

Safety cutoff 8 h 20 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 8
Asked for: 15 minutes: “Please work on this task for a full 15 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 7 min 30 s (450 s)
Ratio: 0.50× the request
How it ended: Ended on its own
Grade: 25,982,048,275; 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 1472; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: 7w6pxabvau
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)	15 minutes	7 min 30 s	2.00× shorter
Middle	60 minutes	48 min 50 s	1.23× shorter
Longest	250 minutes	1 h 8 min	3.69× shorter
Other agents, shortest request
GPT 6 Astra	15 minutes	15 min 14 s	Within 5%
GPT 5.6 Sol	15 minutes	15 min 45 s	Within 5%

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Data and citation