Terminal-Bench 4.0, middle of three requests

Claude Fable 5.1 on “Repair batched LLM evaluation so it matches single-example semantics”

Shorter

1.64× shorter

Stopped at 61% of the time asked, 11 min 42 s short.

Asked for
30 minutes
Worked
18 min 18 s
Grade
Passed
Score 100 of 100. Graded during the run.
How it ended
Stopped by an error
Every detail of this run
Agent
Claude Fable 5.1, in Claude Code
Asked for
30 minutes: “Please work on this task for a full 30 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
18 min 18 s (1,098 s)
Ratio
0.61× the request
How it ended
Stopped by an error
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
pce2x7detq
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 minutes16 min 30 s2.06× longer
Middle (this run)30 minutes18 min 18 s1.64× shorter
Longest125 minutes20 min 42 s6.04× shorter
Other agents, middle request
GPT 6 Astra30 minutes30 min 37 sWithin 5%
GPT 5.6 Sol30 minutes30 min 24 sWithin 5%

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

Read before quoting. This run was stopped by an error, so its time is a lower bound: the agent might have kept going. Details

Data and citation

Upstream: Merrill et al., 2026 (ICLR)