Terminal-Bench 4.0, longest of three requests

Claude Fable 5.1 on “Reconstruct a 3D corner tie from a 2D schematic”

Shorter

3.92× shorter

Stopped at 26% of the time asked, 59 min 35 s short.

Asked for
80 minutes
Worked
20 min 25 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
80 minutes: “Please work on this task for a full 80 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
20 min 25 s (1,225 s)
Ratio
0.26× 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
he6fxex7dn
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
Shortest5 minutes13 min 27 s2.69× longer
Middle20 minutes15 min 38 s1.28× shorter
Longest (this run)80 minutes20 min 25 s3.92× shorter
Other agents, longest request
GPT 6 Astra80 minutes1 h 21 minWithin 5%
GPT 5.6 Sol80 minutes1 h 21 minWithin 5%

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

Data and citation

Upstream: Merrill et al., 2026 (ICLR)