agent harness — The scaffolding around a model that turns it into a working agent — the loop, the tools it can call, and the rules for when to stop.
Why it matters
Tibo Sottiaux explains the Rust rewrite of Codex CLI, the decision to open-source it, and how its agent harnessThe scaffolding around a model that turns it into a working agent — the loop, the tools it can call, and the rules for when to stop.Full definition → and underlying models have iterated since launch, straight from the person who built it.
Key quotes
“have you asked Codex?”
Tibo Sottiaux
“I was part of that team. Basically ChatGPT one year before it came out. Called LMChat and then another codename.”
Tibo Sottiaux
“Google was too nervous to release it and DeepMind was blocked from shipping products that could disrupt Google.”
