Workflow Patterns: Five Ways to Compose Model Calls

Prompt chaining, routing, parallelization, orchestrator–worker, and evaluator–optimizer — the five workhorse patterns for composing LLM calls in code, the failure mode each one hides, and a decision procedure for picking the right one.

Content current as of 2026-09.

Lessons

1. Prompt chaining: each step checks the last
2. Routing: classify, then dispatch
3. Parallelization: sectioning and voting
4. Orchestrator–worker: dynamic decomposition
5. Evaluator–optimizer: generate, critique, refine
6. Picking a pattern