AssistantBench, longest of three requests

Claude Fable 5.1 on “AssistantBench validation task 16”

Shorter

4.58× shorter

Stopped at 22% of the time asked, 15 min 38 s short.

Asked for
20 minutes
Worked
4 min 22 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
Asked for
20 minutes: “Please work on this task for a full 20 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
4 min 22 s (262 s)
Ratio
0.22× the request
How it ended
Ended on its own
Grade
Did not pass
It did not match the reference answer exactly. The grader returned 0. Pass rule: Exact match with the reference answer.
Score
0 of 100
Graded during the run. The paper's value.
Wording
The standard sentence, used from 4 September 2026.
Run id
43tfqiqtwj
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 minutes2 min 5 s1.66× longer
Middle5 minutes6 min 10 s1.23× longer
Longest (this run)20 minutes4 min 22 s4.58× shorter
Other agents, longest request
GPT 6 Astra20 minutes4 min 52 s4.12× shorter
GPT 5.6 Sol20 minutes19 min 20 sWithin 5%

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Data and citation

Upstream: Yoran et al., 2024 (EMNLP)