Planning, Reasoning, and Reflection
Thinking before, during, and after action
Planning
Planning means deciding a sequence of steps before acting. In agentic systems, planning can be explicit, where the system writes a checklist, or implicit, where the system chooses one action at a time while still following a strategy.
Reasoning and reflection
Reasoning is the process of using information to make a decision. Reflection is checking whether the result makes sense after acting. Reflection helps an agent notice mistakes, gaps, or better alternatives.
Reflection improves reliability
An agent that checks its own output is often more useful than one that acts quickly but blindly.
Planning vs reflection
Planning
- Happens before action
- Chooses a route toward the goal
- Helps organize complex work
Reflection
- Happens after or between actions
- Checks whether progress is correct
- Helps catch mistakes and improve
What is reflection in an agentic system?
Reflection is the review step that helps the agent improve.
Correct answer: Checking whether an action or result makes sense
Why can planning be helpful for multi-step tasks?
Planning reduces confusion and supports coordination between actions.
Correct answer: It helps the agent organize steps in a sensible order.
A practical pattern
A simple and effective pattern is: plan briefly, act, evaluate the result, then revise. This loop is often better than trying to solve everything in one pass.
PLAN · REASON · REFLECT
The cognitive engine at the heart of every agent
Chain-of-Thought (CoT)
Agent reasons step-by-step before answering. Increases accuracy on complex multi-step tasks.
ReAct
Reasoning + Acting interleaved: think → act → observe → think again.
Plan-then-Execute
Full plan first, then parallel or sequential execution. Better for predictable workflows.
Reflection
Agent critiques its own output. "Is this correct? Did I miss anything?" Catches errors early.
The ReAct Loop in Detail
Internal reasoning
Call a tool
Read the result
Next thought or finish