diff --git a/docs/install/docker.md b/docs/install/docker.md
index a65abe58872..d7856be3c8e 100644
--- a/docs/install/docker.md
+++ b/docs/install/docker.md
@@ -261,7 +261,11 @@ For gotchas and troubleshooting, see [Bonjour discovery](/gateway/bonjour).
 
 Docker Compose bind-mounts `OPENCLAW_CONFIG_DIR` to `/home/node/.openclaw` and
 `OPENCLAW_WORKSPACE_DIR` to `/home/node/.openclaw/workspace`, so those paths
-survive container replacement.
+survive container replacement. When either variable is unset, the bundled
+`docker-compose.yml` falls back to `${HOME}/.openclaw` (and
+`${HOME}/.openclaw/workspace` for the workspace mount), or `/tmp/.openclaw`
+when `HOME` itself is also missing. That keeps `docker compose up` from
+emitting an empty-source volume spec on bare environments.
 
 That mounted config directory is where OpenClaw keeps: