Adding Pyrefly Type Checking to Your Agentic Loop
Coding agents are writing more Python than ever. Tools like Claude, Copilot, Cursor, and Codex generate entire features with little-to-no user interaction. But in large projects, this generated code is prone to type errors, mismatched signatures, and subtle API misuse. Incorporating static analysis directly into the agentic loop can mean the difference between returning from your break with a production-ready feature or needing several more correction cycles.
Type checking sits right in the sweet spot for agents. It's fast enough for iterating small fixes, robust enough to catch issues of varying complexity, and actionable enough for an agent to make changes. In this post, we walk through how to integrate Pyrefly into your agentic workflow so that every piece of generated code can get type checked automatically.
TL;DR: We recommend:
- Adding a skill file for your agent with an
agent.mddirective to ensure the project checks clean before finishing a feature. - If your model doesn't trigger this reliably, set up a hook on the Stop event.