Mind · Reasoning

ReAct

Interleaved thought-action-observation cycle

Definition

Mechanism

An interleaved reasoning-action loop where the agent cycles through Thought (reason about the situation), Action (invoke a tool or take a step), and Observation (process the result). Unlike pure Chain-of-Thought which reasons then answers, ReAct interleaves reasoning with environmental feedback, allowing the agent to adjust plans based on real-world results. It interleaves reasoning traces for a Task with ToolInvoke execution, updating the context with observation results.

Preconditions

  1. Environment access
  2. Goal

Postconditions

  1. Goal reached or deemed impossible

Invariants

  1. Action based on reasoning
  2. Cycle of Thought-Action-Observation

Risks

Failure modes

  1. Observation Blindness

    Agent ignores observations and follows initial plan.

  2. {{loop}} Explosion

    Endless thought-action cycles without termination.

  3. Action {{cognitive_bias}}

    Jumping to actions without sufficient reasoning.

Relationships

Builds on

Accepts

Infrastructure

Task

The atomic unit of intent

Composes with

Infrastructure

ToolInvoke

Execute external tool and observe result

References

Agent

Autonomous Goal-Directed Entity

Infrastructure

Chain

Sequential data container (linked list)

Infrastructure

CognitiveBias

Structural processing error definition

Infrastructure

Loop

Repeated execution cycle

Used by

References

EventReact

Responding to external triggers rather than polling

Reference

Identity

Ref
ReAct#3361
Sema ID
sema:ReAct#mh:SHA-256:3361fd75537995da1d70c0f60b9b8bd01c44bad9e2596a81fa059b7c6c3fba83
Ring
2
Tier
1
Updated
2026-11-11
Supersedes
  • sema:ReAct#mh:SHA-256:b4879d75afcfc4c7fe1d0b48f3e65b7ad2953a9b8c2a236f2cf3a2b7f98c9688
  • sema:ReAct#mh:SHA-256:c72018c3dbdfe960eadd257f10dfd88400a405cfd2be557977fc0e81bcae8062
  • sema:ReAct#mh:SHA-256:bf894b5668550ecb0031e3f015d07aa7f6023bb9fa37d89c5982b67188797bfe
  • sema:ReAct#mh:SHA-256:5281c82a8338b19ed33253f3447b6e845a967e6a28acb8c3efb63a6ab24ff308
  • sema:ReAct#mh:SHA-256:23310635be1d832c320f40f2f954751ec909e9fc7ed85314946ccbb85ef8b524