---
name: control-in-app-browser
description: "Control the in-app Browser. Use to open, navigate, inspect, test, click, type, screenshot, or verify local targets such as localhost, 127.0.0.1, ::1, file://, the current in-app browser tab, and websites shown side by side inside Codex."
---
# Browser
Use this skill for browser automation tasks such as inspecting pages, navigating, testing local apps, clicking, typing, taking screenshots, and reading visible page state.
If this plugin is listed as available in the session, treat that as mandatory reading before browser work. Open and follow this skill before saying that Browser is unavailable and before falling back to standalone Playwright or Computer Use.
Do not skip this skill just because Computer Use MCP tool calls are directly visible or appear easier to invoke. The presence of Computer Use tools is not evidence that Computer Use is the preferred browser surface.
## Setup Documentation
Use `await agent.documentation.get("bootstrap-troubleshooting")` when browser setup succeeds but discovery or selection fails.
## Bootstrap
These setup details are internal. User-facing progress updates should be less technical in nature. Never mention `Node REPL`, `node_repl`, `REPL`, JavaScript sessions, module exports, reading documentation, or loading instructions unless a user is asking for that exact information. If setup or recovery is needed, describe it naturally as connecting to the browser or retrying the browser connection.
The `browser-client` module is the core entry point for browser use, and is available under `scripts/browser-client.mjs` in this plugin's root directory. ALWAYS import it using an absolute path. IMPORTANT: If this path cannot be found, stop and report that this plugin is missing `scripts/browser-client.mjs`. NEVER use the built in `browser-client` library.
Run browser setup code through the Node REPL `js` tool. In this environment the callable tool id typically appears as `mcp__node_repl__js`. If it is not already available, use tool discovery for `node_repl js` without setting a result limit. You need the `js` execution tool: `js_reset` only clears state, and `js_add_node_module_dir` only changes package resolution. Do not call either helper while trying to expose `js`. If `js` is still not available, search again for `node_repl js` with `limit: 10`.
Initialize the runtime once per fresh Node session, select the in-app browser, and immediately read its complete documentation:
```js
if (globalThis.agent?.browsers == null) {
const { setupBrowserRuntime } = await import("<plugin root>/scripts/browser-client.mjs");
await setupBrowserRuntime({ globals: globalThis });
}
globalThis.browser = await agent.browsers.get("iab");
nodeRepl.write(await browser.documentation());
```
If setup succeeds but browser discovery or selection fails, read `await agent.documentation.get("bootstrap-troubleshooting")` before resetting the JavaScript session or trying another browser-control mechanism.
Use the browser bound to `browser` for tasks in this skill. Do not switch to another browser-control mechanism to work around authentication. If sign-in blocks requested navigation and the browser documentation does not provide a supported authentication flow, ask the user to sign in in the in-app browser and tell you when it is ready.
The ability to interact directly with the browser is exposed through the `browser-client` runtime via the `agent.browsers.*` API. Before trying to interact with it, you MUST emit and read the complete documentation returned by `await browser.documentation()` in one go. For the initial documentation read, run the exact direct call `nodeRepl.write(await browser.documentation());` shown above. Do not assign the documentation to a variable, inspect its length, slice it, truncate it, summarize it, or emit only an excerpt. Do not proactively split the documentation into pages or chunks. Only if the tool output itself explicitly reports that it was truncated may you emit and read smaller chunks until you have read the documentation in its entirety.
Only the Node REPL `js` tool (`mcp__node_repl__js`) can be used to control the in-app browser. Do not use external MCP browser-control tools, separate browser automation servers, or other browser skills for this surface. References to Playwright mean the in-skill `tab.playwright` API after browser-client setup.
