invisible-playwright-mcp

A stealth Firefox browser, exposed as an MCP server, so any AI agent can browse and act on real websites without being blocked by anti-bot systems.

It wraps invisible-playwright (a real Firefox patched at the C++ source for stealth) and hands your MCP client the usual browser tools: navigate, click, type, read, screenshot. The browser is always launched by the stealth engine, so the fingerprint is set inside the engine, not bolted on.

Install (Claude Code)

One line:

claude mcp add stealth --env STEALTHFOX_PROXY=http://user:pass@host:port -- uvx invisible-playwright-mcp

Or add it to any MCP client via a config block (Claude Code, Cursor, Claude Desktop):

{
  "mcpServers": {
    "stealth": {
      "command": "uvx",
      "args": ["invisible-playwright-mcp"],
      "env": { "STEALTHFOX_PROXY": "http://user:pass@host:port" }
    }
  }
}

uvx downloads and runs it in one step; no manual install. The stealth Firefox engine is fetched automatically on first use.

Configuration (environment variables)

Tools

session_new_page, session_list_pages, session_select_page, session_close_page, browser_navigate, browser_read_text, browser_snapshot, browser_read_html, browser_click, browser_click_at, browser_type, browser_press_key, browser_evaluate, browser_take_screenshot.

browser_click_at takes viewport coordinates instead of a selector, moves the pointer there rather than teleporting, optionally holds before releasing, and returns a screenshot of what happened - for a slider, a canvas-drawn challenge, or a press-and-hold.

browser_snapshot returns the title, the url and the visible interactive elements rather than the accessibility tree: one country <select> on a real sign-up page contributes about two hundred <option> nodes, which fill the character budget before the form does.

Each element comes with a selector when one can reach it, and that string goes to browser_click or browser_type verbatim. It is built to match exactly one element, which the obvious selector often does not: measured across 958 elements on real pages, 88% could be addressed but only 48% unambiguously, and Playwright acts on the first match without complaining, so aiming at the third of five identical links quietly hit the first. Elements no selector can reach carry at instead, the centre coordinates, for browser_click_at.

When a click does not land, the error says what stopped it rather than only that it timed out: an element covering the target is named, with its id, its class and its text, because the next move is to deal with that thing and not to retry. If the page has replaced getBoundingClientRect so that nothing can be measured, the snapshot reports unmeasurable with a count instead of an empty list, so a tampered page cannot be mistaken for a page with no controls.

When an element has none of those, the selector falls back to data-testid and then to a unique aria-label, which together took coverage from 90.5% of elements to 97.9%. It stops there: a text-based selector is not stable, and a handle that sometimes points elsewhere is the thing this exists to remove. What is left carries at and nothing else.

A link addressed by its href has no separate href field, because the selector already holds it: a[href='/cart'] says where the link goes as plainly as the field did, and not repeating it is what kept this affordable (+47% of the payload with the repetition, +15% without). A link addressed by its id keeps its href, having nothing duplicated.

browser_read_html returns the page's markup instead of a flat list, for when the structure is what matters: a form and its labels, a table, what a control is wired to. The browser decides what is actually painted, on a clone of the document so the live page is never written to, and the markup is then reduced to what is worth reading. Measured on real pages, 9.6 MB of markup became 293 KB with every one of the 1,453 interactive elements still present. mode is form (the interactive surface and the text explaining it), text (the prose alone) or full (the structure, with the noise and the attribute soup gone).

Tool names mirror the Microsoft Playwright MCP, so prompts written for it work here too.

Watching it work, and more than one client

Over stdio the browser belongs to the client that opened it. Set STEALTHFOX_MCP_TRANSPORT=http and it does not: the session is owned by the server, so a second client can attach to the browser the first one left open, and closing a client no longer kills the browser.

STEALTHFOX_MCP_TRANSPORT=http uvx invisible-playwright-mcp

Two pages come with it, on the same port, and neither is an MCP tool. That is deliberate: a tool result goes into the model's context, so a view refreshing twice a second would spend a whole context window on pictures of a page nobody asked about.

http://127.0.0.1:8765/live is what the browser is looking at right now. It never starts a browser, it only reports one that is already running, and it says so plainly when nothing is.

http://127.0.0.1:8765/ is a two-pane shell: a conversation on the left, that same live view on the right. There is no model behind it. What it has is a placeholder that understands a handful of literal commands (go <url>, read [selector], click <selector>, type <selector> <text>, shot) and says so when you type anything else. It exists so the seam a model plugs into is exercised rather than imagined, and it goes through exactly the same code the MCP tools do, so whatever it can do a client can do too.

The difference between the two is the rule the code follows: the view observes and the chat acts. Opening /live never starts a browser, it only reports one that is already there. Typing a command into the chat does start one, the same way a tool call would.

Notes

• Bring your own proxy. The engine does the stealth; a residential proxy gives you the matching IP and geography. Without one it still runs, but the exit is your own address.
• This is a browser, not a captcha solver. It does not solve or bypass challenges for you; it makes an ordinary Firefox session look like a real one.

License

See the engine project, invisible-playwright.