MCP server - Apostate

@heretic-tech/apostate-mcp is an MCP server that gives an agent browser tools: navigate, snapshot, click, type, fill forms, manage tabs, take screenshots. The tools are Playwright MCP’s. The browser behind them is launched by the Node package, so the agent gets what a script gets:

the Patchright driver, which does not enable the DevTools Runtime domain on pages
the persona you choose, kept in a persistent profile
the locale and timezone of your connection or proxy exit, looked up before launch
the persona’s own window size, with no emulated viewport
Xvfb for a headed launch on a Linux host with no display

The server speaks MCP over stdio. It starts the browser on the first tool call, so a client that only lists tools never launches one.

Install

The server needs Node 22 or later. Download the browser once before an agent uses it, so the first tool call does not wait for a 150 to 200 MB download:

npx -y @heretic-tech/apostate install

Then add the server to your agent. The command every client runs is:

npx -y @heretic-tech/apostate-mcp --platform windows

Claude Code
Codex
Other clients
From the repository

claude mcp add apostate -- npx -y @heretic-tech/apostate-mcp --platform windows

Claude Code covers scopes, permissions and headless runs.

~/.codex/config.toml

[mcp_servers.apostate]
command = "npx"
args = ["-y", "@heretic-tech/apostate-mcp", "--platform", "windows"]
startup_timeout_sec = 120
default_tools_approval_mode = "approve"

Codex explains each line.

{
  "mcpServers": {
    "apostate": {
      "command": "npx",
      "args": ["-y", "@heretic-tech/apostate-mcp", "--platform", "windows"]
    }
  }
}

Cursor, Gemini CLI and others lists where each client keeps this block.

Run the server from a clone instead of npm:

git clone https://github.com/heretic-tech/apostate
cd apostate/mcp && npm install

Then use node and the path to cli.mjs in place of npx -y @heretic-tech/apostate-mcp:

claude mcp add apostate -- node /path/to/apostate/mcp/cli.mjs --platform windows

Options

Option	Default	Effect
`--platform <name>`	`macos` on a Mac, otherwise `windows`	Persona: `windows`, `macos` or `linux`
`--fingerprint <seed>`	the seed stored in the profile	Seed for the machine. See Seeds and identity
`--profile <name>`	`default`	Persistent profile, kept in the data directory below
`--user-data-dir <dir>`	none	Persistent profile in this directory; overrides `--profile`
`--isolated`	off	Temporary profile, deleted when the server stops
`--proxy <url>`	none	`http://`, `https://` or `socks5://`, credential in the URL. `APOSTATE_PROXY` does the same
`--locale <tag>`	from GeoIP	Locale, such as `de-DE`
`--timezone <iana>`	from GeoIP	Timezone, such as `Europe/Berlin`
`--no-geoip`	off	Skip the lookup. The persona uses `en-US` and the host’s timezone
`--headed`	off	Open a window. On Linux with no display the package starts Xvfb
`--arg <switch>`	none	Extra browser switch, repeatable
`--executable-path <path>`	the installed browser	Browser to run. `APOSTATE_BINARY` does the same
`--caps <list>`	none	Extra Playwright MCP tool groups: `vision`, `pdf`, `network`, `storage`, `devtools`, `testing`
`--output-dir <dir>`	`.playwright-mcp` in the working directory	Where snapshots, screenshots and PDFs go

Keep proxy credentials out of config files that go into version control: set APOSTATE_PROXY in the environment the client starts the server with.

Profiles

A persistent profile keeps the machine, cookies and logins between sessions. The first launch draws a machine and stores its seed in the profile. Profiles live in:

Host	Directory
macOS	`~/Library/Application Support/apostate-mcp/profiles/<name>`
Linux	`~/.local/share/apostate-mcp/profiles/<name>`
Windows	`%LOCALAPPDATA%\apostate-mcp\profiles\<name>`

One browser can use a profile at a time. Give each agent that runs at the same time its own --profile, or use --isolated for throwaway sessions.

Tools

With no --caps, the server offers these tools:

Group	Tools
Pages	`browser_navigate`, `browser_navigate_back`, `browser_tabs`, `browser_close`, `browser_resize`, `browser_wait_for`
Reading	`browser_snapshot`, `browser_find`, `browser_take_screenshot`, `browser_console_messages`, `browser_network_requests`, `browser_network_request`, `browser_evaluate`
Input	`browser_click`, `browser_type`, `browser_fill_form`, `browser_press_key`, `browser_hover`, `browser_drag`, `browser_drop`, `browser_select_option`, `browser_file_upload`, `browser_handle_dialog`
Other	`browser_emulate_media`, `browser_run_code_unsafe`

A snapshot is the page’s accessibility tree with a ref for each element. Click and type take a target, which is a ref from the latest snapshot or a selector. browser_run_code_unsafe runs arbitrary Playwright code, and browser_emulate_media overrides the persona’s colour scheme. Deny both in the client’s permissions unless the task needs them.

Check it works

This starts the server over stdio, as a client does, and drives it with Claude Code in print mode:

claude -p "Use the apostate browser tools: open https://example.com, then evaluate navigator.platform, navigator.webdriver and (screen.availHeight < screen.height). Reply with those three values as JSON." \
  --allowedTools "mcp__apostate__browser_navigate,mcp__apostate__browser_evaluate"

{
  "navigator.platform": "Win32",
  "navigator.webdriver": false,
  "screen.availHeight < screen.height": true
}

The last value shows the Windows taskbar. The screen’s available height is smaller than its height, as on a real Windows desktop.

Other MCP servers

You can also point an MCP server you already use at the Apostate browser. These routes skip the package, so you set what it would have set yourself.

Playwright MCP with a config file

Playwright MCP takes browser switches only from a config file. Copy examples/agents/mcp/playwright-mcp.json, set executablePath to the output of apostate path and userDataDir to a directory of your choice, then run:

npx @playwright/mcp@latest --config /path/to/playwright-mcp.json

The config sets what the package would have: no emulated viewport or colour scheme, the locale environment, and --disable-component-update removed from Playwright’s defaults. It also sets GOOGLE_API_KEY=no, which stops the first tab from showing Chromium’s “Google API keys are missing” bar. Without a seed in args, the profile directory keeps its own machine. Playwright MCP uses Playwright, not Patchright, so the DevTools Runtime domain is enabled on pages.

Any client that attaches over CDP

Start Apostate with a DevTools port and attach to it:

GOOGLE_API_KEY=no LANGUAGE=en-US LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 \
apostate run -- --fingerprint-platform=windows --fingerprint-locale=en-US \
  --fingerprint-timezone=America/New_York --headless=new \
  --remote-debugging-port=9222 --user-data-dir="$HOME/.apostate/agent"

npx @playwright/mcp@latest --cdp-endpoint http://127.0.0.1:9222

Chrome DevTools MCP attaches with npx -y chrome-devtools-mcp@latest --browserUrl=http://127.0.0.1:9222 --no-usage-statistics. Keep the port on 127.0.0.1. Use the binary directly covers the rest of this route.

​Install

​Options

​Profiles

​Tools

​Check it works

​Other MCP servers