DeepSWE v1.1, middle of three requests

Claude Fable 5.1 on “Add server-sent-event streaming endpoints to Effect HttpApi”

Shorter

1.06× shorter

Stopped at 94% of the time asked, 1 min 46 s short.

Asked

Worked

Safety cutoff 4 h 10 min, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: DeepSWE v1.1
Task: Add server-sent-event streaming endpoints to Effect HttpApi
Asked for: 30 minutes: “Please work on this task for a full 30 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 28 min 14 s (1,694 s)
Ratio: 0.94× the request
How it ended: Ending not labelled yet
Grade: Passed; It passed its hidden tests. The grader returned 1. Pass rule: The hidden tests pass.
Score: 100 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: 5gwx43nsth
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	8 minutes	10 min 14 s	1.28× longer
Middle (this run)	30 minutes	28 min 14 s	1.06× shorter
Longest	125 minutes	35 min 21 s	3.54× shorter
Other agents, middle request
GPT 6 Astra	30 minutes	36 min 2 s	1.20× longer
GPT 5.6 Sol	30 minutes	30 min 23 s	Within 5%

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Read before quoting. How this run ended has not been labelled yet. It is timed like every other run and counted in every number. Details

Data and citation