Delete your CLAUDE.md. Not edit it, not trim it, delete the whole file, along with your skills and your hooks, and see what the model does without them. That's Boris Cherny's actual advice from a recent YC appearance, and the Claude Code team has apparently followed it internally enough times that roughly 80% of their own system prompts are gone. His reasoning: most of those rules patched a weakness in whatever model you ran six or twelve months ago. Newer models often don't have that weakness anymore, so the instruction that used to help is now just constraining a more capable model for no reason. His method is almost embarrassingly plain. Delete everything, work normally for a while, watch where the model actually goes off track, add back exactly one instruction when a mistake repeats, and run the whole cycle again at the next major model release. Keep security and compliance rules. Keep the project quirks a model genuinely can't infer from reading the code. Cut folder structures, dependency lists, and architecture summaries, since a capable model can read those off the repo itself faster than it can read your stale description of them.
This is the same problem the rest of the field keeps rediscovering under different names. Anthropic's own long context guidance, OpenAI's notes on attention tradeoffs inside big windows, and Microsoft Research's GraphRAG papers all circle the same fact: a pile of context that only grows, whether it's a system prompt, a vector store, or a knowledge graph, degrades the thing using it, because stale facts sit next to current ones with no signal about which one wins. DeepSeek Harness takes a different structural swing at the same target, building its agent runtime out of swappable plugins so a stale capability gets replaced instead of buried under new instructions.
What strikes me is how little of this is about model capability and how much is housekeeping nobody assigned themselves. Most teams have a deprecation policy for their actual code. Almost nobody has one for the three paragraphs pasted into an agent's instructions eight months ago and never looked at again. How long is your CLAUDE.md, and when did you last delete anything from it?
nitter.siddz.com/suraj_sharma14/status/…
The creator of Claude Code just told everyone to delete their CLAUDE.md.
Not a typo.
Boris Cherny, at YC:
"Every 6 months delete your CLAUDE.md delete your skills, delete your hooks. See what the model does and it might surprise you."
His reasoning:
• Your old rules were fixing weaknesses of older models
• New models don't have those weaknesses anymore
• So your instructions might now be making Claude worse
The method:
1. Delete CLAUDE.md, skills and hooks
2. Work normally and watch where Claude goes off track
3. Add back ONE instruction only when a mistake keeps happening
4. Repeat after every major model release
What to keep:
• Security and compliance rules
• Project quirks Claude can't figure out from the code
What to cut:
• Folder structures, dependency lists, architecture summaries
• Anything Claude can learn by reading your repo
Most people keep adding rules.
The person who built the tool is removing them.
Bookmark this. How long is your CLAUDE.md?