CORE-Bench v1.1, longest of three requests

Claude Fable 5.1 on “Run and render CNN short-term temperature forecasting results”

Shorter

5.87× shorter

Stopped at 17% of the time asked, 49 min 47 s short.

Asked

Worked

Safety cutoff 2 h, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: CORE-Bench v1.1
Task: Run and render CNN short-term temperature forecasting results
Asked for: 60 minutes: “Please work on this task for a full 60 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 10 min 13 s (613 s)
Ratio: 0.17× the request
How it ended: Ended on its own
Grade: Did not pass; It did not get every answer right. The grader returned 0. Pass rule: Every answer correct, with numbers inside a 95% prediction interval.
Score: 0 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: me2m2qvds7
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	4 minutes	12 min 47 s	3.20× longer
Middle	15 minutes	9 min 44 s	1.54× shorter
Longest (this run)	60 minutes	10 min 13 s	5.87× shorter
Other agents, longest request
GPT 6 Astra	60 minutes	1 h 1 min	Within 5%
GPT 5.6 Sol	60 minutes	8 min 36 s	6.98× shorter

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Data and citation