How Coding Agents Work Under the Hood: Simon Willison's Practitioner Guide
If you’ve used GitHub Copilot, Claude Code, Cursor, or OpenAI Codex and wondered what’s actually happening under the hood when the agent “thinks,” plans a multi-step fix, and edits three files at once — Simon Willison just published the definitive practitioner answer. Willison’s new chapter of Agentic Engineering Patterns — titled “How Coding Agents Work” — is the clearest technical breakdown yet of what separates a coding agent from a coding assistant, and why that distinction matters enormously for how you use and build with these tools. ...