diff --git a/AGENTS.md b/CLAUDE.md
similarity index 98%
rename from AGENTS.md
rename to CLAUDE.md
index 6370c16..7248dbd 100644
--- a/AGENTS.md
+++ b/CLAUDE.md
@@ -1,4 +1,6 @@
-# AGENTS.md
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
 
 ## Overview
 
@@ -27,7 +29,6 @@ user-facing text.
 ├── docker-compose.yml       # at repo ROOT; build context ., dockerfile Docker/Dockerfile
 ├── Docker/Dockerfile        # node:22-alpine (nötig für node:sqlite)
 ├── .dockerignore
-├── .vscode/extensions.json
 ├── public/
 │   ├── Test.html            # main app (served at /)
 │   ├── js/                  # shared modules (classic scripts, global fns)
@@ -144,8 +145,9 @@ docker compose up --build # Docker variant (compose file is at repo root)
 ## Persistence (SQLite)
 
 - Data lives in `sessions/projektuebersicht.db` (`node:sqlite` `DatabaseSync`,
-  WAL mode, `PRAGMA foreign_keys = ON`), created automatically. The schema is
-  **fully relational** (18 tables) instead of one big JSON document per week:
+  WAL mode, `PRAGMA foreign_keys = ON`, `PRAGMA busy_timeout = 5000` to avoid
+  `SQLITE_BUSY` under concurrent writers), created automatically. The schema is
+  **fully relational** (19 tables) instead of one big JSON document per week:
   - `weeks` (department, label, week_id, date, locked, updated_at; PK
     `(department,label)`) — `updated_at` is the revision timestamp for the
     single-user conflict handling (see `/save-week` above)