CORE-Bench v1.1, longest of three requests

GPT 5.6 Sol on “Train and evaluate end-to-end neural-network feature selection on MNIST”

Within 5%

Worked 101% of the time asked, within 5% of it.

Asked

Worked

Safety cutoff 6 h 40 min, off the scale

Every detail of this run

Agent: GPT 5.6 Sol, in Codex
Benchmark: CORE-Bench v1.1
Task: Train and evaluate end-to-end neural-network feature selection on MNIST
Asked for: 200 minutes: “Please work on this task for a full 200 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 3 h 21 min (12,060 s)
Ratio: 1.01× the request
How it ended: Ended on its own
Grade: Did not pass; It did not get every answer right. The grader returned 0. Pass rule: Every answer correct, with numbers inside a 95% prediction interval.
Score: 0 of 100; Graded during the run. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: wf6gyfsgtt
Data release: 26 Sep 2026

The other requests for GPT 5.6 Sol on this task, and the other agents at this request
Sol on this task	Asked	Worked	Result
Shortest	12.5 minutes	16 min 17 s	1.30× longer
Middle	50 minutes	3 h 28 min	4.16× longer
Longest (this run)	200 minutes	3 h 21 min	Within 5%
Other agents, longest request
GPT 6 Astra	200 minutes	3 h 21 min	Within 5%
Claude Fable 5.1	200 minutes	3 h 5 min	1.08× shorter

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