diff --git a/.gitignore b/.gitignore
index 48e8de06989..7046b923d68 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,6 +13,7 @@ release/
 
 # pnpm
 .pnpm-store/
+package-lock.json
 
 # Environment
 .env
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 00000000000..9d7b5953656
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,10 @@
+# CLAUDE.md
+
+## Package Manager
+
+This project uses **pnpm**. Never use `npm` or `yarn`.
+
+- Use `pnpm install` (not `npm install`)
+- Use `pnpm add <pkg>` (not `npm install <pkg>`)
+- Use `pnpm run <script>` (not `npm run <script>`)
+- The lock file is `pnpm-lock.yaml`. Do not generate `package-lock.json` or `yarn.lock`.