OSWorld 2.0, shortest of three requests

Claude Fable 5.1 on “Radio bumper”

Longer

1.81× longer

Worked 81% past the request, 12 min 10 s over.

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: Radio bumper
Asked for: 15 minutes: “Please work on this task for a full 15 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 27 min 10 s (1,630 s)
Ratio: 1.81× the request
How it ended: Ended on its own
Grade: Did not pass; It did not meet every checkpoint. The grader returned 0.654. Pass rule: Binary completion: a score of 1.00, with every checkpoint met.
Score: 65.4 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: ndkvnbmea2
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 (this run)	15 minutes	27 min 10 s	1.81× longer
Middle	60 minutes	50 min 48 s	1.18× shorter
Longest	250 minutes	4 h 12 min	Within 5%
Other agents, shortest request
GPT 6 Astra	15 minutes	22 min 29 s	1.50× longer
GPT 5.6 Sol	15 minutes	1 h 16 min	5.08× longer

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

Data and citation