🚨Breaking: The guy who created Claude Code (
@bcherny) just revealed how his team actually trains their AI.
One file: CLAUDE.md
You place it at the root of your project.
Inside it:
past mistakes
conventions
rules
Claude reads it every session.
The result?
The agent improves over time without you touching the code.
Every bug that gets fixed becomes a permanent rule.
Boris Cherny uses this internally at Anthropic every day.
Here’s the template he shared — ready to copy, paste, and adapt.
CLAUDE.md Template
1. Plan Mode Default
Enter plan mode for any non-trivial task (3+ steps or architectural decisions)
If something goes wrong, 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
2. Subagent Strategy
Use subagents frequently to keep the main context window clean
Offload research, exploration, and parallel analysis to subagents
For complex problems, throw more compute via subagents
Assign one task per subagent for focused execution
3. Self-Improvement Loop
After any correction from the user, update tasks/lessons.md with the pattern
Write rules for yourself to prevent repeating the same mistake
Ruthlessly iterate on these lessons until the mistake rate drops
Review lessons at the start of each session
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, and demonstrate correctness
5. Demand Elegance (Balanced)
For non-trivial changes, ask: “Is there a more elegant solution?”
If a fix feels hacky, ask:
“Knowing everything I know now, implement the elegant solution.”
Skip this for simple fixes — don’t over-engineer
Challenge your own work before presenting it
6. Autonomous Bug Fixing
When given a bug report: just fix it
Use logs, errors, and failing tests to diagnose
Require zero context switching from the user
Fix failing CI tests automatically
Task Management
1. Plan First – Write the plan in tasks/todo.md with checkable items
2. Verify Plan – Confirm the plan before implementation
3. Track Progress – Mark items complete as you go
4. Explain Changes – Provide a high-level summary at each step
5. Document Results – Add a review section to tasks/todo.md
6. Capture Lessons – Update tasks/lessons.md after corrections
Core Principles
Simplicity First
Make every change as simple as possible and minimize code impact.
No Laziness
Find root causes. Avoid temporary fixes. Maintain senior-level engineering standards.