Test-Driven Development with AI

Why TDD with Agents

Agents perform best when they have a clear, verifiable target. Tests give the agent an objective definition of "done" — it can run them, see failures, fix code, and iterate until they pass. This produces cleaner, more correct implementations than asking for code directly.

The Cycle: Red → Green → Refactor

Phase 1: Red — Write Failing Tests

Tell the agent: "We're doing TDD. Write tests for [feature] based on these input/output pairs. Do NOT write any implementation yet."