This is an adapted excerpt from a guide in my AI Knowledge Hub. The full interactive version is linked at the end.
Agentic design patterns are named control structures for arranging LLM calls and tools. This post gives you the decision rule for picking one, the exact shape of each pattern, and the cost each adds — so you can match a task to the minimum structure that solves it. Everything here is model-agnostic and grounded in Anthropic's Building Effective Agents and the Claude Agent SDK.
Workflow vs. agent: the split that decides everything
Anthropic divides all agentic systems into two categories, and the split decides every downstream tradeoff:
Category
