diff --git a/.env.macmini.example b/.env.macmini.example
index 1dfb26efc..3c15c2013 100644
--- a/.env.macmini.example
+++ b/.env.macmini.example
@@ -1,6 +1,18 @@
 # Mac Mini Production Environment
 # Copy to .env.macmini and fill in the values
 
+# ============================================
+# Compose project name (pinned, do not change)
+# ============================================
+# All Mac Mini containers were originally created under this project
+# name, which mismatches the current directory name (mana-monorepo).
+# Pinning the project name here means anyone running 'docker compose ...'
+# from the repo root automatically lands in the same project as the
+# already-running containers, instead of silently spawning a duplicate
+# project with the same compose file. Removing this line WILL break
+# the next deployment.
+COMPOSE_PROJECT_NAME=manacore-monorepo
+
 # ============================================
 # Database (PostgreSQL)
 # ============================================