AI browser automation you can actually see, running inside the Chrome you are already signed into

Fazm ships Playwright MCP in extension mode. When PLAYWRIGHT_USE_EXTENSION is set to true, the bridge appends --extension to the Playwright args (see acp-bridge/src/index.ts lines 1029 to 1031). That flag tells Playwright to connect to a Chrome Web Store extension called Playwright MCP Bridge, with extension ID mmlmfjhmonkocbjadbfplnigmagldckm. Once the extension is installed and you paste the one-time auth token from the Fazm setup window, Playwright drives the Chrome you are already running, with your existing profile, cookies, SSO sessions, and browser fingerprint intact. If the extension is not present, Playwright falls back to launching its own fresh Chromium.

Every page the agent controls gets a full-viewport element with id fazm-overlay injected at z-index 2147483647 (the maximum 32-bit signed int, so nothing else can stack above it). It renders four soft radial gradient wings at the edges of the page and a small centered status pill that reads 'Browser controlled by Fazm · Feel free to switch tabs or use other apps'. The overlay uses pointer-events:none, so it is visible but never intercepts clicks. You can see the exact CSS and DOM in acp-bridge/browser-overlay-init.js lines 16 to 68. The overlay exists because the user needs to know when the AI is driving so they can stop it if it starts doing something unexpected, and because on a real Chrome with real logins the psychological cost of not knowing is higher than on a fresh sandbox.

Those are variations on the same shape: the agent gets a screenshot or a DOM snapshot from a browser the user does not own (cloud-hosted Chromium, or a chrome profile the vendor runs). Fazm is the inversion. The browser the agent drives is the exact Chrome.app you double-clicked this morning, in your own macOS user account, with your own extensions and saved passwords. The agent gets accessibility snapshots, not screenshots, and those snapshots are saved to /tmp/playwright-mcp as YAML files with numbered refs like [ref=e1]. Inline base64 image responses are stripped out at the MCP layer by launching Playwright with --image-responses omit (acp-bridge/src/index.ts line 1033), so the model never eats a screenshot even when a cloud competitor would have sent one.

The overlay uses pointer-events:none on the root and all of its children. CSS pointer-events:none makes the element completely transparent to the mouse: hovers, clicks, text selection, scroll wheels all go straight through to whatever is under it. So you see the glow and the status pill, but every click you make lands on the actual page. That is the whole point. The agent and the user can share the same tab in real time. You can watch the AI fill a form, take over mid-field to fix an autocomplete, then hand it back by typing into Fazm again.

No. Fazm registers five MCP servers as peers, not just Playwright. The list is hardcoded as a Set in acp-bridge/src/index.ts at line 1266 with exactly these names: fazm_tools, playwright, macos-use, whatsapp, google-workspace. When the task needs to rename a file in Finder, open a macOS setting, or paste something into the native WhatsApp app, the agent switches to macos-use or whatsapp, which drive those apps through the real macOS Accessibility API (AXUIElement, kAXFocusedWindowAttribute, etc.) rather than pixel guessing. So AI browser automation here is a subset of something bigger, and the same English sentence can start in Chrome and finish in Finder without a seam.

A consumer app. There is no npm install, no API key to generate, no Python script to run, no docker compose up. You download a signed notarized Mac app, grant Accessibility and Screen Recording permissions, optionally install the Playwright MCP Bridge extension from the Chrome Web Store, and type English into a floating bar. Under the hood it runs the Claude Agent SDK against the five bundled MCP servers, but that is an implementation detail the user does not touch.

At boot it runs a real round-trip through the accessibility API, not just AXIsProcessTrusted which caches stale values on macOS 26 Tahoe. The function is testAccessibilityPermission in Desktop/Sources/AppState.swift, starting at line 433. It grabs the frontmost app, calls AXUIElementCreateApplication on its PID, then tries to read kAXFocusedWindowAttribute back. Success, noValue, and attributeUnsupported all count as 'working'. If it gets cannotComplete, it re-runs against Finder specifically (lines 468 to 485) to disambiguate a real broken permission from an app that simply does not implement AX. If Finder also fails, the code falls back to creating a CGEvent tap as a last-resort probe of the live TCC database. That three-stage check is why the agent can trust the tree.

Because the agent also needs to work outside the browser. In Chrome, Playwright hands back its own structural snapshot. But Gmail, Slack, Finder, Mail, Settings, Notes, Xcode, VSCode, and Catalyst apps like WhatsApp do not have a DOM the agent can query. They do publish to the macOS Accessibility API (the same surface screen readers use), which exposes a typed tree of roles, labels, bounds, and children for every UI element. By using the accessibility tree as the canonical ground truth for any surface, Fazm gets one mental model that spans Chrome plus the rest of your Mac, instead of a browser-only model that quits at the URL bar.

The overlay is injected via Playwright's page.evaluate on every page load, not via addInitScript (which does not work reliably on CDP-connected contexts in extension mode). See the comment block at the top of acp-bridge/browser-overlay-init.js. That means if a single-page app re-renders its body, the overlay re-injects on the next load event. If the page is a hardened origin that aggressively rewrites its own DOM, the overlay can be cosmetically displaced, but the agent's control path is independent of it. The overlay is a transparency signal, not a load-bearing component.

It installs the Playwright MCP Bridge extension from the Chrome Web Store, at chromewebstore.google.com/detail/playwright-mcp-bridge/mmlmfjhmonkocbjadbfplnigmagldckm. This is an open-source bridge that lets a local Playwright process drive the Chrome window over a localhost channel. Once installed, you paste a bridge token into its options page (Fazm generates the token in BrowserExtensionSetup.swift and stores it under UserDefaults key 'playwrightExtensionToken'), then the setup window runs a connection probe to confirm the local Playwright can reach the extension. After that, any command you give Fazm that involves a URL routes through this extension into your real Chrome, not a separate Chromium.