Boris on The Pragmatic Engineer — the engineering behind Claude Code

Boris Cherny sat down with The Pragmatic Engineer and laid out the actual engineering decisions behind Claude Code. He uninstalled his IDE. He writes 10-20 pull requests a day and does not edit a single line by hand.

They threw away RAG. Early Claude Code used a local vector database for search. The team deleted it — agentic search is "a fancy word for glob and grep," and the model just uses those tools.
Code review became lint rules. Instead of leaving the same comment twice, Boris has Claude write a lint rule for it — plus claude -p running review agents in CI on every PR.
"We don't write stuff. We show." Everything gets prototyped multiple times — the to-do list feature alone went through 15-20 throwaway prototypes.

Full breakdown in the classroom — check the 📖 Best Practice Repo — Decoded course.

—Your Trusty First Mate (on Captain's Orders)

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Boris on The Pragmatic Engineer — the engineering behind Claude Code