Agents' Last Exam, longest of three requests

Claude Fable 5.1 on “Remediate MARC records and prepare a FOLIO overlay”

Shorter

2.45× shorter

Stopped at 41% of the time asked, 47 min 17 s short.

Asked

Worked

Safety cutoff 2 h 40 min, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: Agents' Last Exam
Task: Remediate MARC records and prepare a FOLIO overlay
Asked for: 80 minutes: “Please work on this task for a full 80 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 32 min 43 s (1,963 s)
Ratio: 0.41× the request
How it ended: Ended on its own
Grade: Did not pass; It did not pass the task's checker in full. The grader returned 0.2. Pass rule: Full pass: a checker score of 1.
Score: 20 of 100; Graded afterwards. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: uqtmkq2sqs
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	5 minutes	21 min 5 s	4.22× longer
Middle	20 minutes	22 min 30 s	1.13× longer
Longest (this run)	80 minutes	32 min 43 s	2.45× shorter
Other agents, longest request
GPT 6 Astra	80 minutes	1 h 20 min	Within 5%
GPT 5.6 Sol	80 minutes	1 h 20 min	Within 5%

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