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invisible-playwright-mcp

invisible-playwright-mcp

invisible-playwright-mcp

A stealth Firefox as an MCP server. Add it to Claude Code, Claude Desktop, Codex, Cursor or any other MCP client, and your assistant gets a real browser: tabs, navigation, reading, clicking, typing, dropdowns, keys, screenshots, a live view of the window, and a JavaScript reader, on a Firefox whose fingerprint is set inside the engine rather than bolted onto the page.

The engine is invisible-playwright, a Firefox patched at the C++ source. This package is the MCP layer over it: every tool below is a thin wrapper, and there is no interface here. The interface, when you want one, is AIHawk.

How to install this, and the two ways to use it, are in AIHawk's README. This page keeps what the server itself owns: the config block for clients that take a file, the settings, and the tools.

Adding it to your client

Claude Code, Codex and Gemini CLI have a command for it, and the command is in AIHawk's README. The rest take a config file, and the file is not the same everywhere: three different top-level keys, and one of them is not even JSON. Find yours below. The block only tells the client how to start the server; installing uv and fetching the engine come first, as AIHawk's README shows.

If your client takes a config file

Most use a top-level mcpServers - Claude Desktop, Cursor, Windsurf, Cline:

{
  "mcpServers": {
    "stealth": {
      "command": "uvx",
      "args": ["invisible-playwright-mcp"]
    }
  }
}

Client

File

Claude Desktop (macOS)

~/Library/Application Support/Claude/claude_desktop_config.json

Claude Desktop (Windows)

%APPDATA%\Claude\claude_desktop_config.json

Cursor

.cursor/mcp.json in the project, or ~/.cursor/mcp.json for every project

Windsurf

~/.codeium/windsurf/mcp_config.json

Cline

~/.cline/data/settings/cline_mcp_settings.json, or the Configure MCP Servers button in its MCP panel, which opens whichever file your version uses

Zed calls the key context_servers, not mcpServers, in ~/.config/zed/settings.json (%APPDATA%\Zed\settings.json on Windows):

{
  "context_servers": {
    "stealth": {
      "command": "uvx",
      "args": ["invisible-playwright-mcp"]
    }
  }
}

VS Code calls it servers, in .vscode/mcp.json for a workspace:

{
  "servers": {
    "stealth": {
      "type": "stdio",
      "command": "uvx",
      "args": ["invisible-playwright-mcp"]
    }
  }
}

Codex uses TOML, in ~/.codex/config.toml:

[mcp_servers.stealth]
command = "uvx"
args = ["invisible-playwright-mcp"]

Continue uses YAML with its own block format, which changed recently enough that we would rather point you at their documentation than print a block here that may already be stale.

Where a proxy and the other settings go

Everything in Settings below goes under env on the server entry, in whatever shape your client uses:

{
  "mcpServers": {
    "stealth": {
      "command": "uvx",
      "args": ["invisible-playwright-mcp"],
      "env": {
        "STEALTHFOX_PROXY": "http://user:pass@proxy.example.com:8080",
        "STEALTHFOX_SEED": "4242"
      }
    }
  }
}

In Codex's TOML that is a [mcp_servers.stealth.env] table; on the command line, Claude Code and Codex take -e KEY=value and --env KEY=value.

⛔ "Added" is not "connected". Every one of these writes a config entry without running anything, so a typo, a missing uv, or the first-run browser download all surface later as a server that will not start. Check before you trust it: claude mcp list, codex mcp list, or your client's MCP panel.

Related MCP server: Local Browser MCP

Settings

Environment variables, all optional. A proxy is the one worth adding: without it the exit IP, timezone and locale are your own machine's, which is a real gap between what the browser says it is and where it appears to be.

Variable

Meaning

STEALTHFOX_PROXY

Proxy URL, e.g. http://user:pass@proxy.example.com:8080 or socks5://proxy.example.com:1080. Host and port are both required. Bring your own. With it set, the session's timezone, locale and egress are derived from the proxy.

STEALTHFOX_NO_PROXY

1 to go out from this machine's own address even when STEALTHFOX_PROXY is set.

STEALTHFOX_SEED

Integer seed for a deterministic fingerprint (same seed, same identity). A profile's own seed wins over this one.

STEALTHFOX_PROFILE_DIR

A directory for a persistent profile, so logins survive across runs.

STEALTHFOX_BINARY

Path to an engine binary you already have. It must be the build the packaged seal pins, or startup refuses.

STEALTHFOX_HEADLESS

0 to run headed; headless by default.

STEALTHFOX_MCP_TRANSPORT

http to serve over streamable HTTP instead of stdio. Default is stdio, which is what MCP clients expect.

STEALTHFOX_MCP_HOST

Bind address for the HTTP transport. Default 127.0.0.1.

STEALTHFOX_MCP_PORT

Port for the HTTP transport. Default 8765, which is also the AIHawk interface's default: change one of the two if you run both.

Anything a tool call says wins over these. session_start can pick another seed, another exit or another profile for one session; the variables are what a session gets when nobody says anything.

Tools

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

Tool names mirror the Microsoft Playwright MCP, so prompts written for it work here too. Three groups: who is browsing and which tab, reading the page, and acting on it.

Session and tabs

Tool

Arguments

What it does

session_status

none

Who is browsing right now: the seed, the exit, the profile and the open tabs. Starts nothing; if no browser is up it says so.

session_start

seed, proxy, profile, all optional

Close whatever is open and start a browser as a particular person. Returns a sentence describing the session it actually started.

session_new_page

none

Open a tab, make it the active one, return its id.

session_list_pages

none

Every open tab: id, title, url, and which one is active.

session_select_page

page_id

Make a tab the active one. Every browser_* tool acts on the active tab.

session_close_page

page_id, optional

Close a tab, or the active one when the id is left out.

You can ignore session_start entirely: the first tool that needs a page starts a session on its own, as a different stranger every time, which is the right default. There is one browser, so two identities are visited in turn, never at once; a task that needs two accounts live at the same time cannot be done here.

  • seed is the identity. Same seed, same fingerprint, every time. Leave it out and one is drawn; the answer says which, so a session worth repeating can be repeated.

  • profile is a directory that keeps cookies and logins between sessions. A profile also owns its seed: the first session on a new one stores the identity inside it and every later session reuses it, so a login never comes back wearing different hardware. Ask for a seed that contradicts the one a profile carries and you get a refusal naming both numbers, never a silent choice. A relative path is resolved against the server's own directory, and the answer reports the full path it used.

  • proxy is where the traffic leaves, http://user:pass@host:port or socks5://host:port. Timezone, locale and geography follow it.

  • Pass "" for profile or proxy to insist on none, even when the environment sets a default. That is how you get sessions a site cannot link to each other.

A profile does not own its exit the way it owns its seed. The same login arriving from another country is as visible as one arriving on different hardware. You are warned when a profile's exit changes, but only when you change it: a provider rotating its own addresses behind one host and port is indistinguishable from here.

A session_start that fails, usually because the proxy is down, leaves nothing running, and every later tool repeats the refusal until a session_start works. It does not quietly start a browser without the exit that was asked for.

Reading the page

Tool

Arguments

What it returns

browser_navigate

url, wait_until

Goes to the url in the active tab, opening one if none exists. wait_until is domcontentloaded by default, which returns as soon as the markup is parsed; load waits for images and stylesheets, networkidle for a single-page app that fetches its content after load.

browser_read_text

selector (default body), max_chars (default 6000)

The visible text of an element, markup gone. The cheapest way to read a page. Long text is cut at max_chars and the cut is marked, so text without the marker is the whole thing.

browser_snapshot

max_chars

Title, url, and the interactive elements that are actually visible, each with a selector when one can reach it and at: [x, y], its centre in viewport pixels. Not the accessibility tree: a single country <select> would contribute about two hundred <option> nodes and fill the cap before the form appears.

browser_read_html

mode: form (default), text, full

The page's HTML reduced to what is worth reading: form keeps the interactive surface and the text explaining it, text the prose alone, full the structure with the noise removed. Not capped, on purpose: cutting markup in the middle leaves tags that mean nothing, so on a large page the answer is long.

browser_take_screenshot

none

A screenshot of the active tab, as an image.

browser_watch

none

The whole browser window as a person at the machine sees it: tab strip, address bar, page and the pointer, from a live capture the session keeps running on the active tab.

The selectors a snapshot hands out are built to match exactly one element, and that is the reason to pass them verbatim rather than writing your own: measured across 958 elements on real pages, 88% could be addressed by a selector but only 48% unambiguously, and Playwright acts on the first match, so a caller aiming at the third of five identical links would silently hit the first.

browser_watch is for the person watching, not for the model acting. The pointer is drawn in the browser chrome on purpose, so that no page can see it, which is also why no page screenshot can ever contain it. The picture is window pixels: feed browser_take_screenshot to browser_click_at, not this. It needs an engine from firefox-28 on; an older engine answers with a sentence saying so.

Acting on the page

Tool

Arguments

What it does

browser_click

selector

Clicks the first element matching a CSS selector, scrolling it into view and waiting for it to be clickable. The pointer approaches, hovers, presses and releases, the way a hand does.

browser_click_at

x, y, hold_seconds (default 0)

Clicks a viewport coordinate instead of a selector: moves the pointer there, presses, holds if asked, releases, and returns a screenshot taken right after. For a slider track, a canvas-drawn challenge, a precise point inside a wider element.

browser_type

selector, text

Fills a field, replacing whatever it holds. It sets the value rather than typing key by key, so per-keystroke handlers such as an autocomplete do not fire; for those, click the field and use browser_press_key.

browser_select_option

selector, value

Chooses an option in a <select>, by its visible label or by its value.

browser_press_key

key

Presses a key on whatever has focus: Enter, Tab, Escape, ArrowDown, Control+a, or a single character.

browser_evaluate

expression

Runs JavaScript to read from the page and returns the result as JSON: a computed style, a value held in a framework's state, the length of a list.

browser_click_at takes coordinates relative to the viewport, not to the page, so the ones in a snapshot go stale the moment anything scrolls: a click, a keypress, a lazy image loading above the fold. Nothing raises when that happens; the click lands on whatever is at that spot now. Take a fresh snapshot after anything that could have moved the page, and prefer browser_click with an element's selector whenever it has one.

browser_evaluate reads; it will not act. Assigning to value, checked or selected, or calling click(), dispatchEvent(), submit() or requestSubmit(), is refused, and the refusal names the tool to use instead. Script reaches the page with no keystroke and no pointer, so the event carries isTrusted false, which is the clearest signal a page can collect that nobody is really there. Reading those properties is fine. The refusal catches the obvious spellings, not every possible one; a script that slips past it is still the wrong way to do the thing.

The order to try them in

The server hands every client this ladder, because a model that cannot find a way down it invents one:

  1. A named tool with a selector: browser_click, browser_type, browser_select_option, browser_press_key. browser_snapshot supplies the selector.

  2. Coordinates: the snapshot reports at: [x, y] for every element, and browser_click_at moves the pointer there. For a canvas, a slider, a map, a widget built out of divs.

  3. A screenshot: browser_take_screenshot, then browser_click_at on what you can see. For what the snapshot does not list at all.

  4. browser_evaluate, to read what none of the above can see.

Getting to the bottom of the ladder without a way to do the thing is a result too: a task reported as impossible is worth more than one completed in a way that gets the session blocked.

Why each tool returns what it does, with the measurements behind it: docs/tool-design.md.

More than one client on the same browser

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        # Linux
$env:STEALTHFOX_MCP_TRANSPORT = "http"; uvx invisible-playwright-mcp   # Windows

To SEE the browser rather than share it, AIHawk shows the live page beside the conversation.

Notes

  • 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.

  • One browser per server process. Tabs are the way to keep several pages open; two identities at once need two servers.

License

MIT, the same as the engine it wraps.

Available Tools

18 tools
browser_clickA

Click the first element matching a CSS selector.

Scrolls it into view and waits for it to be clickable. When no selector can describe the target, use browser_click_at with coordinates from browser_snapshot.

Inputs: selector (required). Returns: result

browser_click_atA

Click (or press-and-hold) a raw viewport coordinate instead of a selector - for targets a selector cannot reliably reach: a slider track, a canvas-drawn captcha, or a precise point inside a wider element. Moves the pointer there first (no teleport), then down, then up, holding first if hold_seconds is set. Returns a screenshot taken right after release.

hold_seconds needs invisible-playwright 0.9.0 or newer to mean anything. In every earlier version the wait it is built on returned instantly, so the press and the release happened in the same frame and the hold never happened - on the one tool that exists for sliders and press-and-hold challenges. The floor in pyproject.toml is set accordingly.

Coordinates are relative to the VIEWPORT, not to the page, so the ones in a snapshot go stale the moment anything scrolls: a click, a keypress, a lazy image loading in above the fold. Nothing raises when that happens - the click simply lands on whatever is at that spot now. Take a fresh snapshot after anything that could have moved the page, and prefer browser_click with the element's selector whenever it has one.

Inputs: x (required), y (required), hold_seconds.

browser_evaluateA

READ from the page with JavaScript and get the result as JSON.

For what the other tools cannot see: a computed style, a value held in a framework's state, the length of a list.

Acting on the page is refused, and the refusal names the tool to use. Assigning to value, checked or selected, or calling click(), dispatchEvent(), submit() or requestSubmit(), changes the page without a real keystroke or pointer, and a page can tell. Use browser_click, browser_type or browser_select_option instead; they do the same thing through the pointer and the keyboard. Reading any of those properties is fine.

The refusal catches the obvious spellings, not every possible one. A script that slips past it is still the wrong way to do the thing: report it in your answer rather than using it.

Inputs: expression (required). Returns: result

browser_navigateA

Go to a url in the active tab, opening one if none exists.

wait_until is "domcontentloaded" by default, which returns as soon as the markup is parsed. Use "load" when the page needs its images and stylesheets, or "networkidle" for a single-page app that fetches its content after load.

Inputs: url (required), wait_until. Returns: result

browser_press_keyA

Press a key on whatever has focus: "Enter", "Tab", "Escape", "ArrowDown", "Control+a", or a single character.

Inputs: key (required). Returns: result

browser_read_htmlA

The page's HTML, cleaned down to what is worth reading.

Use this when the STRUCTURE matters - a form and its labels, a table, what a control is wired to. browser_snapshot gives a flat inventory of things to click; this keeps the markup and the relationships inside it.

mode="form" keeps the interactive surface and the text explaining it, mode="text" returns the prose alone, mode="full" keeps the structure with the noise and the attribute soup removed.

Unlike browser_read_text this is NOT capped: it returns the whole reduced page, which on a large one is tens of thousands of characters. That is deliberate, because cutting markup in the middle leaves tags that no longer mean anything - but it means the answer can be long. Reach for browser_snapshot when you only need something to click, or browser_read_text when you only need the words.

Inputs: mode. Returns: result

browser_read_textA

The visible text of an element, with the markup gone.

The cheapest way to read a page. Narrow the selector when you know where the answer is; use browser_read_html instead when the structure matters, or browser_snapshot when you need something to click.

Long text is cut at max_chars (6000 by default) and the cut is marked in what comes back, so text that ends without that marker is the whole thing.

Inputs: selector, max_chars. Returns: result

browser_select_optionA

Choose an option in a dropdown (<select>), by its visible label or by its value.

Use this rather than clicking the dropdown and pressing arrow keys: a click plus arrows cannot tell you which row it landed on, and setting the value through browser_evaluate changes it without the page seeing a real interaction.

Inputs: value (required), selector (required). Returns: result

browser_snapshotA

Title, url, and the interactive elements that are actually visible.

Each element carries a selector when one can reach it: pass that string 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, so a caller aiming at the third of five identical links would silently hit the first.

Elements with no selector carry at, the centre coordinates, for browser_click_at.

Not the accessibility tree: on a real sign-up page a single country <select> contributes about two hundred <option> nodes, which fill the character cap before the form the caller was looking for appears at all.

Inputs: max_chars. Returns: result

browser_take_screenshotA

One screenshot of the active tab, on demand.

Inputs: no named parameters.

browser_typeA

Fill a field, replacing whatever it holds.

This sets the value rather than typing key by key, so it will not fire the per-keystroke handlers an autocomplete needs. For those, click the field and use browser_press_key.

Inputs: text (required), selector (required). Returns: result

browser_watchA

The whole browser window as a person at the machine sees it: tab strip, address bar, the page and the pointer, from a live capture kept running on the active tab. For watching the work, not for acting on it: the picture is window pixels, so do not feed its coordinates to browser_click_at; use browser_take_screenshot for that.

Inputs: no named parameters.

session_close_pageA

Close a tab, or the active one when page_id is left out.

Inputs: page_id. Returns: result

session_list_pagesA

Every open tab: id, title, url, and which one is active.

Use it before session_select_page: the id alone does not tell you which tab you are switching to.

Inputs: no named parameters. Returns: result

session_new_pageA

Open a new tab and make it the active one. Returns its page id.

Tabs persist across calls and across clients, so this is how you keep one page while working on another rather than navigating back and forth.

Inputs: no named parameters. Returns: result

session_select_pageA

Switch the active tab. Every other browser_* tool acts on it.

Take the id from session_list_pages or from session_new_page.

Inputs: page_id (required). Returns: result

session_startA

Start a browsing session as a particular person, and say who that is.

Call this when you want to control WHO is browsing: a fresh stranger, the same person as last time, or a saved profile that is already logged in somewhere. Calling it closes whatever browser is open and starts another, so anything not saved in a profile is gone.

You do not have to call it at all. The first tool that needs a page starts a session on its own; session_status then tells you who that turned out to be.

There is only ONE browser. Two identities are visited in turn, never at the same time, so a task that needs both accounts live at once cannot be done here and is worth saying so rather than half-starting.

seed the browser identity. Same seed, same fingerprint, every time. Leave it out and one is drawn, and the answer tells you which, so you can ask for it again later. profile a directory that keeps cookies and logins between sessions. A profile also KEEPS ITS SEED: the first session on a new one stores the identity inside it, and every session after reuses it, so a login does not come back wearing different hardware. Pass "" to insist on no profile at all, which is how you get sessions a site cannot link to each other. A relative path is resolved against the server's own directory, so the answer reports the full path it used. proxy where the traffic goes out, as http://user:pass@host:port or socks5://host:port. Pass "" to insist on going out from this machine's own address. A profile does NOT pin its exit the way it pins its seed: timezone, locale and geography come from the exit, so the same login arriving from another country is as visible as one arriving on different hardware. You are warned when a profile's exit changes, but only when YOU change it - a provider that rotates its own addresses behind one host and port looks identical here.

Inputs: seed, proxy, profile. Returns: result

session_statusA

Who is browsing right now: the identity, the exit, the profile and the tabs.

Ask whenever you need to know which person the browser currently is, or from where its traffic leaves. The seed is what you would pass to session_start to become this person again, so this is also how you record a session that is worth repeating.

It starts nothing. If no browser is running yet it says so, because until one is running there is no identity to report.

Inputs: no named parameters. Returns: result

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

Loading tool schema changelog…

    TDQS

    A4.2/5.0

    Scored across 18 tools

    Disambiguation5/5

    Each tool targets a distinct operation: session lifecycle, tab management, navigation, reading modes, and input actions are cleanly separated. Even the overlapping read tools (text, HTML, snapshot) explicitly describe when to use each, so an agent can select them without ambiguity.

    Naming Consistency4/5

    The set consistently uses snake_case with `session_*` and `browser_*` prefixes and mostly action+object names like `browser_select_option` and `session_close_page`. Minor noun-style exceptions such as `session_status` and `browser_snapshot` are small deviations but do not break the overall pattern.

    Tool Count4/5

    18 tools is slightly above the typical 3-15 sweet spot, but for browser automation each tool earns its place by covering a distinct capability. There is little redundant filler, so the count feels reasonable rather than bloated.

    Completeness4/5

    The surface covers session/identity management, tab lifecycle, navigation, multiple read modes, and the common input actions well. Obvious gaps are minor—no explicit wait-for-selector, hover, upload, or back/forward—but agents can usually work around them using navigate, wait_until, click, or press_key.

    Maintenance

    ActivityNo data
    ResponsivenessSyncing

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