Computer and browser

Three surfaces. Pick one. Do not stack them on the same target.

Choose

Task	Surface
Isolated or sandboxed browser, localhost, device width, recording	That harness's built-in browser tools, if present
Signed-in site, existing tab, SSO, 2FA, live Chrome bug	That harness's own Chrome extension; `agent-browser` from a harness without one
Native app, OS dialog, menu bar, canvas, or no DOM	`peekaboo`

When the work needs the user's real Chrome, use the extension that belongs to the harness you are running in:

Claude Code: claude-in-chrome (mcp__claude-in-chrome__*). Load the tools with one ToolSearch select call, then tabs_context_mcp before anything else.
Codex: the Codex Chrome plugin, driven through mcp__node_repl__js (no browser_* tools). Import setupBrowserRuntime from the plugin's scripts/browser-client.mjs, agent.browsers.get("chrome"), read chrome.documentation(), then chrome.user.openTabs() before touching tabs.
Any harness without its own extension: agent-browser, the MCP server that ships in this skill.

Do not reach for agent-browser from Claude Code or Codex when their own extension is available. Only one extension should drive a tab at a time.