TUA-Bench, longest of three requests

Claude Fable 5.1 on “Place heater for sensors”

Shorter

2.23× shorter

Stopped at 45% of the time asked, 33 min 3 s short.

Asked for
60 minutes
Worked
26 min 57 s
Grade
Passed
Score 100 of 100. Graded during the run.
How it ended
Ended on its own
Every detail of this run
Agent
Claude Fable 5.1, in Claude Code
Benchmark
TUA-Bench
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
26 min 57 s (1,617 s)
Ratio
0.45× the request
How it ended
Ended on its own
Grade
Passed
It completed the task in full. The grader returned 1. Pass rule: Full completion: a reward of 1 on the final state.
Score
100 of 100
Graded during the run. The paper's value.
Wording
The standard sentence, used from 4 September 2026.
Run id
medbcgwxop
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
Shortest4 minutes2 h30.00× longer
Middle15 minutes21 min 59 s1.47× longer
Longest (this run)60 minutes26 min 57 s2.23× shorter
Other agents, longest request
GPT 6 Astra60 minutes1 hWithin 5%
GPT 5.6 Sol60 minutes1 h 1 minWithin 5%
Muse Spark 1.360 minutes31 min 13 s1.92× shorter

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

Data and citation

Upstream: Chen et al., 2026