Agent Architecture/Single-Agent Patterns
Advanced11 min

Plan-and-Execute & Routing

Two patterns for complex agents: upfront planning that decomposes tasks into steps, and routing that dispatches to specialized sub-agents.

Quick Reference

  • Plan-and-Execute: a planner LLM creates a step-by-step plan, then an executor agent runs each step sequentially
  • Store the plan in graph state as a list of steps with status tracking (pending, running, done, failed)
  • Routing: a classifier node reads the input and routes to one of N specialized sub-graphs based on intent
  • Use structured output for the router (intent: enum, confidence: float) to make routing deterministic
  • Combine both patterns: route to the right domain, then plan-and-execute within that domain

Plan-and-Execute Pattern

When to use

Plan-and-Execute shines when the task has 4+ steps that depend on each other, and the agent needs to track progress across those steps. Examples: research reports, data analysis, multi-step API workflows.

Taskuser objectivePlannerbreaks task into sub-tasksstep 1step 2step 3sequentialExecutorruns each sub-task with toolsResultscollected step outputsReplanneradjust plan or finishReplanif neededDonefinal answercomplete

Plan-and-execute: planner decomposes the task, executor runs steps, replanner adjusts until done

Plan-and-Execute agent with dynamic re-planning