docs(browser-control): document OPENCLAW_EAGER_BROWSER_CONTROL_SERVER requirement

liuhao1024 · liuhao1024 · commit 10ba5706b954 · 2026-06-14T10:46:56.000+08:00
The standalone loopback HTTP API only starts when OPENCLAW_EAGER_BROWSER_CONTROL_SERVER=1 is set in the gateway service environment. Without it, browser control works via CLI and agent tools but nothing listens on the loopback control port. Fixes #92841
diff --git a/docs/tools/browser-control.md b/docs/tools/browser-control.md
@@ -13,7 +13,12 @@ CLI, and scripting patterns (snapshots, refs, waits, debug flows).
 
 ## Control API (optional)
 
-For local integrations only, the Gateway exposes a small loopback HTTP API:
+For local integrations only, the Gateway exposes a small loopback HTTP API.
+This standalone server is opt-in — set the environment variable
+`OPENCLAW_EAGER_BROWSER_CONTROL_SERVER=1` in the gateway service environment
+and restart the gateway before the HTTP endpoints become available. Without
+this variable the browser control runtime still works through the CLI and
+agent tools, but nothing listens on the loopback control port.
 
 - Status/start/stop: `GET /`, `POST /start`, `POST /stop`
 - Tabs: `GET /tabs`, `POST /tabs/open`, `POST /tabs/focus`, `DELETE /tabs/:targetId`
