From ad0ac2ae47a564c74e57a0080ba15a2d68aa014a Mon Sep 17 00:00:00 2001
From: Tobias <96661824+CrazyWolf13@users.noreply.github.com>
Date: Sun, 18 Jan 2026 13:13:42 +0100
Subject: [PATCH] add heredoc rule

---
 docs/AI.md | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/docs/AI.md b/docs/AI.md
index 1d7e5dfb1..489a4b35d 100644
--- a/docs/AI.md
+++ b/docs/AI.md
@@ -477,6 +477,24 @@ $STD sudo -u postgres psql -d mydb -c "CREATE EXTENSION IF NOT EXISTS postgis;"
 PG_DB_NAME="mydb" PG_DB_USER="myuser" PG_DB_EXTENSIONS="postgis" setup_postgresql_db
 ```
 
+### 17. Writing Files Without Heredocs
+```bash
+# ❌ WRONG - echo / printf / tee
+echo "# Config" > /opt/app/config.yml
+echo "port: 3000" >> /opt/app/config.yml
+
+printf "# Config\nport: 3000\n" > /opt/app/config.yml
+cat config.yml | tee /opt/app/config.yml
+```
+
+```bash
+# ✅ CORRECT - always use a single heredoc
+cat <<EOF >/opt/app/config.yml
+# Config
+port: 3000
+EOF
+```
+
 ---
 
 ## 📝 Important Rules