diff --git a/.env.example b/.env.example
index 0821ea4..1e0a95d 100644
--- a/.env.example
+++ b/.env.example
@@ -1,4 +1,8 @@
+# Docker Compose build target: "local" or "remote" (selects Dockerfile target)
+# CONVERSION_MODE=local
+
 # Conversion engine: "local" (in-process Docling) or "remote" (Docling Serve)
+# Set automatically by the Docker target — override only for local dev
 # CONVERSION_ENGINE=local
 
 # Docling Serve settings (remote mode only)