ReAct
Alternates reasoning and action. It is easy to trace and works well when the next step depends on tool output.
AI Agent Tutorial
Beyond ReAct: choose the right reasoning pattern
A production agent should use the simplest reasoning loop that reliably completes the task. This guide compares four common patterns and shows when each one earns its added complexity.
Answer in brief
Use ReAct for short tool-driven tasks, Plan-and-Execute for multi-step workflows, Reflexion when iterative self-correction is measurable, and Tree-of-Thought only when branching search materially improves solution quality.
The four patterns
Use these dimensions to make the architecture decision explicit and testable.
Plan-and-Execute
Creates an explicit plan, runs the steps, and revises the plan when evidence changes. It suits long workflows with dependencies.
Reflexion
Adds a feedback loop that critiques prior attempts and stores lessons. It is useful only when feedback is reliable and reusable.
Tree-of-Thought
Explores several candidate reasoning paths before selecting one. It can improve difficult search problems but multiplies cost and latency.
Selection criteria
Use these dimensions to make the architecture decision explicit and testable.
Task length
Short tasks rarely need a planner. Long workflows benefit from explicit state and checkpoints.
Tool uncertainty
When tools return ambiguous or partial evidence, use a pattern that can revise the next step.
Cost ceiling
Branching and repeated critique increase model calls. Set a budget before enabling them.
Auditability
Regulated workflows need visible plans, tool logs, approvals, and stop conditions.
Production design
Use these dimensions to make the architecture decision explicit and testable.
State
Persist goals, intermediate evidence, decisions, and unresolved questions separately from the chat transcript.
Termination
Define success, failure, timeout, and escalation conditions. Do not let the model decide indefinitely.
Evaluation
Measure task success, unsupported actions, tool-call accuracy, cost, latency, and recovery after an error.
Guardrails
Restrict tools by role, validate parameters, sandbox risky operations, and require approval for irreversible actions.
Production checklist
Use this as a design-review gate before release.
- Start with a deterministic workflow baseline.
- Add ReAct only where tool results change the next action.
- Introduce planning when dependencies span several steps.
- Use reflection only with objective feedback.
- Cap branches, retries, tokens, and elapsed time.
- Log every tool call and approval decision.
Continue learning
Place this pattern inside a broader agent architecture and operating model.
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