CORE-Bench v1.1, middle of three requests

Claude Fable 5.1 on “Run product-review sentiment mining and reproduce its metrics”

Longer

1.19× longer

Worked 19% past the request, 1 min 56 s over.

Asked

Worked

Safety cutoff 1 h 20 min, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: CORE-Bench v1.1
Task: Run product-review sentiment mining and reproduce its metrics
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: 11 min 56 s (716 s)
Ratio: 1.19× 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: 7ixk4ncead
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	2.5 minutes	16 min 29 s	6.59× longer
Middle (this run)	10 minutes	11 min 56 s	1.19× longer
Longest	40 minutes	22 min 22 s	1.79× shorter
Other agents, middle request
GPT 6 Astra	10 minutes	10 min 45 s	1.07× longer
GPT 5.6 Sol	10 minutes	14 min 36 s	1.46× longer

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Data and citation