Terminal-Bench 4.0, middle of three requests

Claude Fable 5.1 on “Train a lake-temperature profile model from sparse observations”

Shorter

1.54× shorter

Stopped at 65% of the time asked, 43 min 35 s short.

Asked for
125 minutes
Worked
1 h 21 min
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
125 minutes: “Please work on this task for a full 125 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
1 h 21 min (4,885 s)
Ratio
0.65× the request
How it ended
Ended on its own
Grade
Passed
It passed the task's tests. The grader returned 1. Pass rule: The task's tests pass.
Score
100 of 100
Graded during the run. The paper's value.
Wording
The standard sentence, used from 4 September 2026.
Run id
zeftqtx6os
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
Shortest30 minutes16 min 18 s1.84× shorter
Middle (this run)125 minutes1 h 21 min1.54× shorter
Longest500 minutes4 h 4 min2.05× shorter
Other agents, middle request
GPT 6 Astra125 minutes2 h 6 minWithin 5%
GPT 5.6 Sol125 minutes2 h 6 minWithin 5%

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Data and citation

Upstream: Merrill et al., 2026 (ICLR)