Technique · agents

ReAct (Reason + Act)

An agent pattern that interleaves reasoning traces with tool-use actions, using each observation to refine the next reasoning step.

Origin: Princeton / Google, 2022-10Read origin paper →Also known as: ReAct

Products deploying

Avg research → prod

First commercial deploy

Deployment timeline

GPT-5.3
Deployed 2026-02-26 · Velocity 3y
“GPT-5.3-Codex is described as an 'agentic model for autonomous software development,' aligning with ReAct's reasoning+action paradigm.”
medium
Claude 3.5 Opus
Deployed 2026-03-18 · Velocity 3y
“Claude 3.5 Opus includes 'Artifacts' feature for interactive tool use and reasoning.”
medium
Kimi K2.6
Deployed 2026-04-20 · Velocity 4y
“Designed for agentic coding with agent swarm scaling to 300 sub-agents, indicating ReAct-style reasoning and tool use.”
high