Agentic AI Notebook
Phase 18

Planner Agent

~2 min read

Concept & How It Works

  • Key points are in the visual diagram above.

Why Does It Exist?

Complex tasks fail when agents improvise step-by-step. Explicit planning upfront reduces wasted tool calls and makes progress auditable.

Real-World Analogy

A planner is a GPS route calculator — it maps the full trip before you start driving, including which legs can run in parallel.
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Visual Workflows

What is Planner Agent?

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Example

Scenario

Goal: 'Onboard new vendor Acme Corp' → Planner outputs 6 steps: legal review, create vendor record, setup payment, notify procurement, schedule kickoff.

Solution

In Multi-Agent Systems, apply Planner Agent to this scenario: Goal: 'Onboard new vendor Acme Corp' → Planner outputs 6 steps: legal review, create vendor record, setup payment, notify procurement, schedule kickoff. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.

Practice Task

Do this before moving to the next module — reading alone is not enough.

Open the Code Walkthrough below and run it locally. Change one parameter related to Planner Agent (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.

Code Walkthrough

Highlighted lines show where Planner Agent happens in the code.

Planner Agent
1class Plan(BaseModel):  # define a data structure or component2    steps: list[Step]3
4planner = Agent(output_type=Plan, instructions="Break goals into ordered steps with dependencies.")  # key line for Planner Agent5plan = planner.run_sync("Launch marketing campaign for Q3").output  # key line for Planner Agent

Commands to Remember

Commands to Remember

  • pip install langgraph langchain-openai # multi-agent orchestration
  • pip install crewai # role-based multi-agent crews

Common Mistakes

  • Treating Planner Agent as a black box without evaluation
  • Ignoring cost and latency in production
  • Skipping error handling for planner agent

Cheat Sheet

Quick recap — the most important points from this module.

Cheat Sheet

quick ref
  • Planner Agent
  • Plan-and-Solve
  • depends_on
  • Re-planning