diff --git a/CLAUDE.md b/CLAUDE.md
index 7587b69..cf20102 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -17,6 +17,7 @@ Behavioral guidelines to reduce common LLM coding mistakes. Merge with project-s
   - ❌ Require explicit command every time: delete repo, force-push to `main`/`master`, rewrite published history, change org permissions
   - Prefer a scoped API token over username/password when one becomes available
 - **Package managers**: `pnpm` (Node), `uv` (Python), `cargo` (Rust)
+- **Web stack**: prefer TypeScript over JavaScript (frontend frameworks, Node backends, scripts); follow the existing project's language choice
 - **Indentation**: 4 spaces by default; follow project convention if different
 
 ## 1. Think Before Coding