diff --git a/apps/api/src/api/tool_instances.py b/apps/api/src/api/tool_instances.py
index 0526ae6..0ae9b09 100644
--- a/apps/api/src/api/tool_instances.py
+++ b/apps/api/src/api/tool_instances.py
@@ -489,7 +489,7 @@ async def stop_instance(
         try:
             await delete_tunnel(
                 tunnel_id=instance.tunnel_id,
-                subdomain=f"instance-{instance.id}",
+                subdomain=f"instance-{str(instance.id)[:8]}",
             )
             logger.info("Deleted tunnel for instance %s", instance.id)
         except Exception as exc:
@@ -546,7 +546,7 @@ async def restart_instance(
         try:
             await delete_tunnel(
                 tunnel_id=instance.tunnel_id,
-                subdomain=f"instance-{instance.id}",
+                subdomain=f"instance-{str(instance.id)[:8]}",
             )
             logger.info("Deleted old tunnel for instance %s", instance.id)
         except Exception as exc:
@@ -634,7 +634,7 @@ async def delete_instance(
         try:
             await delete_tunnel(
                 tunnel_id=instance.tunnel_id,
-                subdomain=f"instance-{instance.id}",
+                subdomain=f"instance-{str(instance.id)[:8]}",
             )
             logger.info("Deleted tunnel for instance %s", instance.id)
         except Exception as exc:
diff --git a/apps/api/src/main.py b/apps/api/src/main.py
index db98f1f..d235b19 100644
--- a/apps/api/src/main.py
+++ b/apps/api/src/main.py
@@ -229,6 +229,18 @@ async def on_startup():
 
     # Seed built-in data
     await seed_builtin_tool_types()
+
+    # Check Cloudflare configuration
+    settings = Settings()
+    if settings.cloudflare_api_token and settings.cloudflare_account_id and settings.cloudflare_zone_id and settings.cloudflare_base_domain:
+        logger.info("Cloudflare tunnel configuration detected: base_domain=%s", settings.cloudflare_base_domain)
+    else:
+        logger.warning(
+            "Cloudflare tunnel configuration incomplete. "
+            "Tunnels will not be created. Set CLOUDFLARE_API_TOKEN, "
+            "CLOUDFLARE_ACCOUNT_ID, CLOUDFLARE_ZONE_ID, and CLOUDFLARE_BASE_DOMAIN."
+        )
+
     logger.info("Startup complete.")
 
 app.include_router(health_router)