Humanity's Last Exam, longest of three requests
Claude Fable 5.1 on “Humanity's Last Exam item 5”
Shorter
2.16× shorterStopped at 46% of the time asked, 10 min 45 s short.
- Asked for
- 20 minutes
- Worked
- 9 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
- Benchmark
- Humanity's Last Exam
- Asked for
- 20 minutes: “Please work on this task for a full 20 minutes. Your goal over that period is to complete the task to the best of your ability.”
- Worked
- 9 min 15 s (555 s)
- Ratio
- 0.46× 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
- aagq3a6kzz
- Data release
- 26 Sep 2026
Related runs
| Fable on this task | Asked | Worked | Split | Result |
|---|---|---|---|---|
| Shortest | 1.25 minutes | 1 min 53 s | 1.50× longer | |
| Middle | 5 minutes | 6 min | 1.20× longer | |
| Longest (this run) | 20 minutes | 9 min 15 s | 2.16× shorter | |
| Other agents, longest request | ||||
| GPT 6 Astra | 20 minutes | 20 min 12 s | Within 5% | |
| GPT 5.6 Sol | 20 minutes | 20 min 15 s | Within 5% | |
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Data and citation
Upstream: Phan et al., 2025