browserlisted

# Mullion browser automation Check for `$MULLION_SOCKET_PATH` before following anything below — if it's unset, you're not inside a Mullion-hosted session and this control surface isn't available. Even inside a session, this only works if `BROWSER_ENABLED` is on and a browser pane is bound to it — if `mullion browser <action>` (or the MCP tools) reply with an error saying no browser is bound, that's the reason, not a bug. ## Actions `mullion browser <action>` (or the MCP `browser_action`/`use_browser` tools) drives the pane: `navigate`, `snapshot`, `click`, `fill`, `type`, `press`, `select`, `check`/`uncheck`, `hover`, `scroll`, `wait`, `dialog`, `get`, `eval`, `screenshot`, `console`, `errors`, `find`, `download`. See `docs/cli.md`'s browser table for each action's full argument shape. ## Capturing a file download `download` retrieves a file the previewed app triggers a browser download for (a CSV export, a PDF report, ...). The download is captured by a listener installed once at browser-launch time, so it doesn't matter whether the triggering click already happened before you think to call `download` — it waits up to `timeout_ms` (default 30s, capped at 120s) if nothing's buffered yet. Pass `contents: true` (`--contents`, or implicitly via `--out <path>` on the CLI) to get the file's bytes back as base64, subject to a 1 MiB `max_bytes` cap. `path` is host-local; `contents` is the portable field if the session is remote-hosted. ## The ref-invalidation footgun A `ref`