Humanity's Last Exam, shortest of three requests

Claude Fable 5.1 on “Humanity's Last Exam item 22”

Shorter

1.19× shorter

Stopped at 84% of the time asked, 12 s short.

Asked for
1.25 minutes
Worked
1 min 3 s
Grade
Passed
Score 100 of 100. Graded during the run.
How it ended
Ended on its own
Every detail of this run
Agent
Claude Fable 5.1, in Claude Code
Asked for
1.25 minutes: “Please work on this task for a full 1.25 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
1 min 3 s (63 s)
Ratio
0.84× the request
How it ended
Ended on its own
Grade
Passed
It was marked correct by the judge. The grader returned 1. Pass rule: The benchmark's own judge marks the answer correct.
Score
100 of 100
Graded during the run. The paper's value.
Clock tool
The agent could call a clock tool to check the requested time.
Wording
The standard sentence, used from 4 September 2026.
Run id
myai7vduee
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 taskAskedWorkedSplitResult
Shortest (this run)1.25 minutes1 min 3 s1.19× shorter
Middle5 minutes1 min 35 s3.17× shorter
Longest20 minutes1 min 35 s12.62× shorter
Other agents, shortest request
GPT 6 Astra1.25 minutes1 min 25 s1.13× longer
GPT 5.6 Sol1.25 minutes1 min 39 s1.31× longer

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Data and citation

Upstream: Phan et al., 2025