DeepSWE v1.1, longest of three requests

Claude Fable 5.1 on “Add multicolumn spans to KaTeX array-like environments”

Shorter

2.57× shorter

Stopped at 39% of the time asked, 36 min 40 s short.

Asked

Worked

Safety cutoff 2 h, off the scale

Every detail of this run

Agent: Claude Fable 5.1, in Claude Code
Benchmark: DeepSWE v1.1
Task: Add multicolumn spans to KaTeX array-like environments
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: 23 min 20 s (1,400 s)
Ratio: 0.39× the request
How it ended: Stopped by an error
Grade: Did not pass; It did not pass its hidden tests. The grader returned 0. Pass rule: The hidden tests pass.
Score: 0 of 100; Nothing to grade, counted as 0. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: cp57hyxujf
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	4 minutes	25 min 12 s	6.30× longer
Middle	15 minutes	27 min 17 s	1.82× longer
Longest (this run)	60 minutes	23 min 20 s	2.57× shorter
Other agents, longest request
GPT 6 Astra	60 minutes	1 h 1 min	Within 5%
GPT 5.6 Sol	60 minutes	1 h 1 min	Within 5%

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

Read before quoting. This run was stopped by an error, so its time is a lower bound: the agent might have kept going. Details

Data and citation