Definition
Plain language
A common pattern where an AI agent alternates between thinking out loud and taking actions.
As stated in the literature
A prompting pattern in which an agent interleaves chain-of-thought reasoning with tool calls and observations in a loop.
Why it matters: Interleaving reasoning with action lets a model both plan and react to real-world feedback, which is the basic ingredient of almost every modern agent.
For example, when asked about the weather, the agent writes "I should call the weather tool for Tokyo," calls it, sees the result, then writes "the temperature is 18°C, so I'll tell the user that."
Heard on the show
“The standard agent, called ReAct, takes them one at a time, cold.”Episode 186 — How a Frozen Model Went From 2% to 77% on Physics Puzzles — Without Retraining