DeepSWE v1.1, middle of three requests

Claude Fable 5.1 on “Add session bundle recording and replay to IPython”

Shorter

1.18× shorter

Stopped at 84% of the time asked, 2 min 20 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 session bundle recording and replay to IPython
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: 12 min 40 s (760 s)
Ratio: 0.84× 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: xi3ugywexi
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	28 min 9 s	7.04× longer
Middle (this run)	15 minutes	12 min 40 s	1.18× shorter
Longest	60 minutes	31 min 2 s	1.93× shorter
Other agents, middle request
GPT 6 Astra	15 minutes	15 min 24 s	Within 5%
GPT 5.6 Sol	15 minutes	15 min 27 s	Within 5%

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

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