Terminal-Bench 4.0, longest of three requests

Claude Fable 5.1 on “Remove latency across a multi-route Next.js warehouse app”

Shorter

2.84× shorter

Stopped at 35% of the time asked, 1 h 21 min short.

Asked for
125 minutes
Worked
44 min 5 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
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
44 min 5 s (2,645 s)
Ratio
0.35× 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
pdgq3lufw4
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
Shortest8 minutes14 min 17 s1.79× longer
Middle30 minutes13 min 35 s2.21× shorter
Longest (this run)125 minutes44 min 5 s2.84× shorter
Other agents, longest 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)