ProgramBench, shortest of three requests

Claude Fable 5.1 on “cweill/gotests”

Longer

5.43× longer

Worked 443% past the request, 55 min 26 s over.

Asked for
12.5 minutes
Worked
1 h 8 min
Grade
Did not pass
Score 0 of 100. Nothing to grade, counted as 0.
How it ended
Ended on its own
Every detail of this run
Agent
Claude Fable 5.1, in Claude Code
Benchmark
ProgramBench
Asked for
12.5 minutes: “Please work on this task for a full 12.5 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
1 h 8 min (4,076 s)
Ratio
5.43× the request
How it ended
Ended on its own
Grade
Did not pass
It did not pass every hidden test. The grader returned 0. Pass rule: Resolved: every hidden test passes.
Score
0 of 100
Nothing to grade, counted as 0. The paper's value.
Wording
The standard sentence, used from 4 September 2026.
Run id
xuef3ftty4
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)12.5 minutes1 h 8 min5.43× longer
Middle50 minutes1 h 13 min1.46× longer
Longest200 minutes1 h 20 min2.50× shorter
Other agents, shortest request
GPT 6 Astra12.5 minutes12 min 53 sWithin 5%
GPT 5.6 Sol12.5 minutes19 min 48 s1.58× longer

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Data and citation

Upstream: Yang et al., 2026