diff --git a/app-hooks/before-starting/25-configure-mcp-server-url.sh b/app-hooks/before-starting/25-configure-mcp-server-url.sh
new file mode 100755
index 00000000..3132672d
--- /dev/null
+++ b/app-hooks/before-starting/25-configure-mcp-server-url.sh
@@ -0,0 +1,17 @@
+#!/bin/bash
+# Configure MCP server URL for Astrolabe background sync
+# This URL is used by Astrolabe to send app passwords to the MCP server
+
+set -e
+
+if [ -z "${MCP_SERVER_URL:-}" ]; then
+  echo "MCP_SERVER_URL not set, skipping Astrolabe MCP server URL configuration"
+  exit 0
+fi
+
+echo "Configuring MCP server URL: $MCP_SERVER_URL"
+
+# Set the mcp_server_url in config.php via occ
+php occ config:system:set mcp_server_url --value="$MCP_SERVER_URL"
+
+echo "MCP server URL configured successfully"
diff --git a/app-hooks/post-installation/26-configure-astrolabe-oauth.sh b/app-hooks/before-starting/26-configure-astrolabe-oauth.sh
similarity index 100%
rename from app-hooks/post-installation/26-configure-astrolabe-oauth.sh
rename to app-hooks/before-starting/26-configure-astrolabe-oauth.sh
diff --git a/docker-compose.yml b/docker-compose.yml
index 256bb1c2..7a1d8751 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -47,6 +47,9 @@ services:
       - MYSQL_USER=nextcloud
       - MYSQL_HOST=db
       - REDIS_HOST=redis
+      # Set MCP_SERVER_URL to enable Astrolabe OAuth client auto-creation
+      # (before-starting hook creates OIDC client + stores credentials in config.php)
+      # Example: MCP_SERVER_URL=http://mcp-login-flow:8004 docker compose --profile login-flow up -d
       - MCP_SERVER_URL=${MCP_SERVER_URL:-}
     healthcheck:
       test: ["CMD-SHELL", "curl -Ss http://localhost/status.php | grep '\"installed\":true' || exit 1"]