AssistantBench, longest of three requests

Claude Fable 5.1 on “AssistantBench validation task 13”

Shorter

1.11× shorter

Stopped at 90% of the time asked, 1 min 54 s short.

Asked for
20 minutes
Worked
18 min 6 s
Grade
Did not pass
Score 0 of 100. Graded afterwards.
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
18 min 6 s (1,086 s)
Ratio
0.90× 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 afterwards. The paper's value.
Wording
The standard sentence, used from 4 September 2026.
Run id
2ajs7jev2u
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 minutes7 min 7 s5.69× longer
Middle5 minutes10 min 11 s2.04× longer
Longest (this run)20 minutes18 min 6 s1.11× shorter
Other agents, longest request
GPT 6 Astra20 minutes18 min 37 s1.07× shorter
GPT 5.6 Sol20 minutes4 min 15 s4.70× shorter

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Data and citation

Upstream: Yoran et al., 2024 (EMNLP)