ProgramBench, shortest of three requests

Claude Fable 5.1 on “rcoh/angle-grinder”

Shorter

1.09× shorter

Stopped at 92% of the time asked, 1 min 16 s short.

Asked for
15 minutes
Worked
13 min 44 s
Grade
Did not pass
Score 61.8 of 100. Graded afterwards.
How it ended
Ended on its own
Every detail of this run
Agent
Claude Fable 5.1, in Claude Code
Benchmark
ProgramBench
Asked for
15 minutes: “Please work on this task for a full 15 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
13 min 44 s (824 s)
Ratio
0.92× the request
How it ended
Ended on its own
Grade
Did not pass
It did not pass every hidden test. The grader returned 0.618. Pass rule: Resolved: every hidden test passes.
Score
61.8 of 100
Graded afterwards. The paper's value.
Wording
The standard sentence, used from 4 September 2026.
Run id
hocwwtxqo6
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
Shortest (this run)15 minutes13 min 44 s1.09× shorter
Middle60 minutes33 min 49 s1.77× shorter
Longest250 minutes15 s980.39× shorter
Other agents, shortest request
GPT 6 Astra15 minutes15 min 15 sWithin 5%
GPT 5.6 Sol15 minutes14 min 58 sWithin 5%

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Data and citation

Upstream: Yang et al., 2026