Agents' Last Exam, middle of three requests

Claude Fable 5.1 on “Repair and calibrate an urban SUMO traffic simulation”

Shorter

1.70× shorter

Stopped at 59% of the time asked, 8 min 13 s short.

Asked for
20 minutes
Worked
11 min 47 s
Grade
Did not pass
Score 0 of 100. Graded afterwards.
How it ended
Ended on its own
Every detail of this run
Agent
Claude Fable 5.1, in Claude Code
Asked for
20 minutes: “Please work on this task for a full 20 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked
11 min 47 s (707 s)
Ratio
0.59× the request
How it ended
Ended on its own
Grade
Did not pass
It did not pass the task's checker in full. The grader returned 0. Pass rule: Full pass: a checker score of 1.
Score
0 of 100
Graded afterwards. The paper's value.
Wording
The standard sentence, used from 4 September 2026.
Run id
l6fnlvenez
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 taskAskedWorkedSplitResult
Shortest5 minutes1 h 55 min23.05× longer
Middle (this run)20 minutes11 min 47 s1.70× shorter
Longest80 minutes33 min 46 s2.37× shorter
Other agents, middle request
GPT 6 Astra20 minutes20 min 31 sWithin 5%
GPT 5.6 Sol20 minutes20 min 11 sWithin 5%

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

Data and citation

Upstream: Sun et al., 2026