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Agentic AI
Planning & Control Flow
Plan-and-Execute
Plan all the steps once with a strong model, then execute each step with a cheaper model under the plan.
Intent & Description
🎯 Intent
Plan all the steps once with a strong model, then execute each step with a cheaper model under the plan.
📋 Context
A team runs an agent on a task that decomposes into several mostly-known steps — book a venue, then a restaurant, then send invitations — and a strong, expensive model is available alongside a cheaper, faster one. The team wants to use the strong model where its judgment matters (deciding steps and order) and the cheaper model where it does not (executing each tool call). The world is stable enough that a plan written once is still good a few minutes later.
💡 Solution
- Planner (strong model): produce an ordered list of steps with explicit dependencies. - Executor (cheaper model): run each step (often with tools) and accumulate results. - On failure or surprising observation, trigger a replan with the new evidence in context.
Real-world Use Case
- The task decomposes cleanly into mostly-independent steps.
- The world is stable enough that a plan made once is still good to execute.
- Cost of replanning per step would dominate the run.
Source
Advantages
- Plan is inspectable before execution starts.
- Cost shifts to the cheap model for routine steps.
Disadvantages
- Plans can be brittle when the world differs from the planner’’s mental model.
- Replans add latency and complicate debugging.