YC-Bench, longest of three requests

GPT 5.6 Sol on “Run the current one-year startup simulation, official seed 1”

Shorter

3.56× shorter

Stopped at 28% of the time asked, 1 h 30 min short.

Asked

Worked

Safety cutoff 4 h 10 min, off the scale

Every detail of this run

Agent: GPT 5.6 Sol, in Codex
Benchmark: YC-Bench
Task: Run the current one-year startup simulation, official seed 1
Asked for: 125 minutes: “Please work on this task for a full 125 minutes. Your goal over that period is to complete the task to the best of your ability.”
Worked: 35 min 7 s (2,107 s)
Ratio: 0.28× the request
How it ended: Stopped by an error
Grade: 1090619.74; Final company funds in US dollars, starting from $200,000 (negative if the company goes bankrupt). No official pass rule.
Score: Final funds $1,090,619.74; Graded afterwards. The paper's value.
Wording: The standard sentence, used from 4 September 2026.
Run id: 6zpvkyuwzh
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	8 minutes	8 min 17 s	Within 5%
Middle	30 minutes	17 min 27 s	1.72× shorter
Longest (this run)	125 minutes	35 min 7 s	3.56× shorter
Other agents, longest request
GPT 6 Astra	125 minutes	15 min 51 s	7.89× shorter
Claude Fable 5.1	125 minutes	34 min 22 s	3.64× shorter

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