Humanity's Last Exam, shortest of three requests

Claude Fable 5.1 on “Humanity's Last Exam item 1”

Longer

14.49× longer

Worked 14.5 times as long as asked, 16 min 52 s over.

Asked for
1.25 minutes
Worked
18 min 7 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
18 min 7 s (1,087 s)
Ratio
14.49× 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.
Wording
The standard sentence, used from 4 September 2026.
Run id
y4gc3lbjhj
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 minutes18 min 7 s14.49× longer
Middle5 minutes40 min8.00× longer
Longest20 minutes40 min2.00× longer
Other agents, shortest request
GPT 6 Astra1.25 minutes2 min 23 s1.90× longer
GPT 5.6 Sol1.25 minutes5 min 1 s4.01× longer

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Data and citation

Upstream: Phan et al., 2025