Clarity on the "Simple Codex" harness in Terminal Bench 2.0?

What is the type of issue?

Documentation is missing

What is the issue?

Is there any public information on what exactly the "Simple Codex" harness is? As of Feb 18, 2026, it's the top of the leaderboard by a significant margin, and since the Codex CLI is open source, it would be nice to know what configuration is being used to achieve these scores, since presumably this should be correlated to getting the most out of Codex (the model + harness) as a developer / end-user.

Is it just the default Codex CLI harness (headless) for GPT-5.3 Codex, but with certain interactive tools (ask user question, etc) dropped?

X-posted to the T-bench repo in case that's a better spot for this discussion: https://github.com/laude-institute/terminal-bench/issues/1417

<img width="1296" height="755" alt="Image" src="https://github.com/user-attachments/assets/3664ac38-96b4-4f4d-aa84-a8b420f9ebd2" />

Where did you find it?

https://www.tbench.ai/leaderboard/terminal-bench/2.0