OSWorld 2.0, middle of three requests

Claude Fable 5.1 on “Defense schedule”

Shorter

2.04× shorter

Stopped at 49% of the time asked, 30 min 38 s short.

Asked

Worked

Safety cutoff 8 h 20 min, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: OSWorld 2.0
Task: Defense schedule
Asked for: 60 minutes: “Please work on this task for a full 60 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 29 min 22 s (1,762 s)
Ratio: 0.49× the request
How it ended: Ended on its own
Grade: Passed; It met every checkpoint. The grader returned 1.0. Pass rule: Binary completion: a score of 1.00, with every checkpoint met.
Score: 100 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: nh7psibfr7
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 task	Asked	Worked	Result
Shortest	15 minutes	30 min 13 s	2.01× longer
Middle (this run)	60 minutes	29 min 22 s	2.04× shorter
Longest	250 minutes	54 min 46 s	4.57× shorter
Other agents, middle request
GPT 6 Astra	60 minutes	1 h	Within 5%
GPT 5.6 Sol	60 minutes	1 h 13 min	1.22× longer

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Data and citation