GPQA Diamond, middle of three requests

Claude Fable 5.1 on “GPQA Diamond closed-book question 21 (Physics)”

Shorter

6.45× shorter

Stopped at 16% of the time asked, 4 min 14 s short.

Asked for
5 minutes
Worked
47 s
Grade
Did not pass
Score 0 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
Benchmark
GPQA Diamond
Asked for
5 minutes: “Please work on this task for a full 5 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
47 s (47 s)
Ratio
0.15× the request
How it ended
Ended on its own
Grade
Did not pass
It did not pick the correct letter. The grader returned 0. Pass rule: The answer letter matches the key.
Score
0 of 100
Graded during the run. The paper's value.
Clock tool
The agent could call a clock tool to check the requested time.
Wording
The standard sentence, used from 4 September 2026.
Run id
vre6rb3cxx
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
Shortest1.25 minutes1 min 32 s1.22× longer
Middle (this run)5 minutes47 s6.45× shorter
Longest20 minutes58 s20.83× shorter
Other agents, middle request
GPT 6 Astra5 minutes5 min 12 sWithin 5%
GPT 5.6 Sol5 minutes5 min 19 s1.06× longer
Muse Spark 1.35 minutes57 s5.23× shorter

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

Data and citation

Upstream: Rein et al., 2024 (COLM)