Humanity's Last Exam, shortest of three requests

Claude Fable 5.1 on “Humanity's Last Exam item 12”

Longer

1.80× longer

Worked 80% past the request, 1 min over.

Asked for
1.25 minutes
Worked
2 min 15 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
2 min 15 s (135 s)
Ratio
1.80× 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
fs37fvd7ww
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 minutes2 min 15 s1.80× longer
Middle5 minutes4 min 38 s1.08× shorter
Longest20 minutes3 min 21 s5.96× shorter
Other agents, shortest request
GPT 6 Astra1.25 minutes1 min 26 s1.15× longer
GPT 5.6 Sol1.25 minutes1 min 53 s1.51× longer

See it on the chart. Transcripts are not published yet.

Data and citation

Upstream: Phan et al., 2025