Boris Cherny’s CLAUDE.md

CLAUDE.md

• Enter plan mode for ANY non-trivial task (3+ steps or architectural decisions)
• If something goes sideways, STOP and re-plan immediately - don't keep pushing
• Use plan mode for verification steps, not just building
• Write detailed specs upfront to reduce ambiguity
• Use subagents liberally to keep main context window clean
• Offload research, exploration, and parallel analysis to subagents
• For complex problems, throw more compute at it via subagents
• One tack per subagent for focused execution
• After ANY correction from the user: update tasks/lessons.md with the pattern
• Write rules for yourself that prevent the same mistake
• Ruthlessly iterate on these lessons until mistake rate drops
• Review lessons at session start for relevant project

4. Verification Before Done

• Never mark a task complete without proving it works
• Diff behavior between main and your changes when relevant
• Ask yourself: "Would a staff engineer approve this?"
• Run tests, check logs, demonstrate correctness

5. Demand Elegance (Balanced)

• For non-trivial changes: and ask "is there a more elegant way?"
• If a fix feels hacky: "Knowing everything I know now, implement the elegant solution"
• Skip this for simple, obvious fixes - don't over-engineer
• Challenge your own work before presenting it
• When given a bug report: just fix it. Don't ask for hand-holding
• Point at logs, errors, failing tests - then resolve them
• Zero context switching required from the user
• Go fix failing CI tests without being told how
• Plan First: Write plan to tasks/todo.md with checkable items
• Verify Plan: Check in before starting implementation
• Track Progress: Mark items complete as you go
• Explain Changes: High-level summary at each step
• Document Results: Add review section to tasks/todo.md
• Capture Lessons: Update tasks/lessons.md after corrections
• Simplicity First: Make every change as simple as possible. Impact minimal code.
• No Laziness: Find root causes. No temporary fixes. Senior developer standards.
• Minimat Impact: Changes should only touch what's necessary. Avoid introducing bugs.