CLAUDE.md is in 359 repositories. The median one runs 1,405 words.
Claude Code's memory file. Shaped like AGENTS.md but with two things it lacks: @path imports, so shared rules live in one place, and a user-scope layer that follows the developer across repos rather than shipping with the code.
AnthropicMeasured
What the nightly counted in real repositories
Counted 13 September 2026Repositories carrying it359 35.2% of the corpus
Files that write down a command39.5%
Files carrying a code block45.3%
Agent behaviour81.3% of 300 root files
Tests63.0% of 300 root files
Code style60.0% of 300 root files
Architecture53.0% of 300 root files
Hard prohibitions52.0% of 300 root files
Git, commits & PRs42.7% of 300 root files
Lint & format40.7% of 300 root files
Setup & install38.3% of 300 root files
Build37.0% of 300 root files
Documentation30.3% of 300 root files
Testing strategy24.0% of 300 root files
Types23.7% of 300 root files
Deploy & release20.3% of 300 root files
Security18.7% of 300 root files
APIs & contracts18.3% of 300 root files
UI & components16.7% of 300 root files
Dependencies16.0% of 300 root files
Database & migrations15.0% of 300 root files
Performance11.7% of 300 root files
Monorepo5.7% of 300 root files
Every night counted
Repositories carrying CLAUDE.md, one column a night
24 nights stored2026-08-01209 to 359 repositories2026-09-13
Asserted
What the documentation says this file can express
Read 2 August 2026FileCLAUDE.md
OwnerAnthropic
Tools that read itClaude Code only
Glob targetingNo
ImportsYes
FrontmatterNo
Nested filesYes
User scopeYes
Read from the format’s own documentation and checked by hand. Capabilities are asserted; adoption is measured.
Always in scope. Project file, plus nested files in subdirectories, plus a user-level file (~/.claude/CLAUDE.md) that applies across every project.
Claude CodeWhat it does well
@path imports, shared conventions written once and pulled into each file
A user-scope file lets personal preferences live outside the team repo
Nested project files compose with the root file rather than replacing it
What it cannot do
Single-vendor: no other agent reads it, so multi-tool teams maintain two files
No glob targeting, same context cost as AGENTS.md, path-scoped rules exist, but in a separate .claude/rules/ file, not in CLAUDE.md itself
Counted pairwise
Repositories that carry CLAUDE.md and something else
Counted 13 September 2026The percentage is of repositories carrying CLAUDE.md, which is the number a “CLAUDE.md versus something” search is really asking for.
AGENTS.md57.7%207 carry both, 33.5% the other wayCursor rules35.1%126 carry both, 40.6% the other wayCopilot instructions18.7%67 carry both, 35.3% the other wayCline rules13.9%50 carry both, 26.6% the other wayGEMINI.md8.6%31 carry both, 64.6% the other wayWindsurf rules7.0%25 carry both, 65.8% the other way.cursorrules4.2%15 carry both, 41.7% the other way
NoRepository and pathCoversScoreChanged
001
microsoft/playwrightCLAUDE.md100 /1001 month ago002
usebruno/bruno.claude/CLAUDE.md100 /100yesterday003
livewire/livewireCLAUDE.md100 /1001 month ago004
airweave-ai/airweaveCLAUDE.md100 /10015 days ago005
stacklok/toolhiveCLAUDE.md100 /1001 month ago006tphakala/birdnet-goCLAUDE.md100 /10029 days ago007nimbalyst/nimbalystpackages/android/CLAUDE.md100 /10023 days ago008
dotCMS/corecore-web/CLAUDE.md100 /100yesterday009tyrchen/geektime-bootcamp-aiw7/genslides/backend/CLAUDE.md100 /1001 month ago010Adit-Jain-srm/NightmareNetCLAUDE.md100 /1001 month ago011
csells/dotprompt_dartCLAUDE.md100 /1001 month ago012
modular/modularCLAUDE.md99 /10015 days ago
microsoft/playwrightCLAUDE.md100 /1001 month ago002usebruno/bruno.claude/CLAUDE.md100 /100yesterday003livewire/livewireCLAUDE.md100 /1001 month ago004airweave-ai/airweaveCLAUDE.md100 /10015 days ago005stacklok/toolhiveCLAUDE.md100 /1001 month ago006tphakala/birdnet-goCLAUDE.md100 /10029 days ago007nimbalyst/nimbalystpackages/android/CLAUDE.md100 /10023 days ago008dotCMS/corecore-web/CLAUDE.md100 /100yesterday009tyrchen/geektime-bootcamp-aiw7/genslides/backend/CLAUDE.md100 /1001 month ago010Adit-Jain-srm/NightmareNetCLAUDE.md100 /1001 month ago011csells/dotprompt_dartCLAUDE.md100 /1001 month ago012modular/modularCLAUDE.md99 /10015 days ago