Arc Control (macOS) MCP server

arc-control-mcp

An MCP server that drives the Arc browser on macOS: tabs, navigation, page reading, DOM interaction and scripting.

It exists because the bundled "Control Chrome" MCP server cannot be pointed at Arc. Arc's scripting dictionary looks like Chrome's, and differs in exactly the places that matter.

Who it is for: anyone running an agent (Claude Code or another MCP client) on a Mac who wants it to work in Arc, the browser they are already signed in to, instead of a fresh automation profile. It reads pages, fills forms, clicks things, runs JavaScript, and keeps its own tabs separate from yours.

What it is not: a cross-platform or cross-browser tool. It drives one browser on one operating system through Apple Events. There is no screenshot tool, no CDP, and no headless mode. There is also no Docker image, and there cannot be one: Apple Events do not cross a container boundary, so a container has no way to reach the Arc running on your Mac. This is a 0.3.0 personal project, and the known limitations below are real.

Requirements

• macOS
• Arc installed
• Node 20 or newer

One runtime dependency, @modelcontextprotocol/sdk. No build step.

Install

Nothing to clone. Any MCP client can start the server with npx, and @latest is also how it upgrades: the next start picks up a new release.

{
  "mcpServers": {
    "arc": {
      "command": "npx",
      "args": ["-y", "arc-control-mcp@latest"]
    }
  }
}

[!IMPORTANT]

That config is not sufficient on its own. Two macOS permissions still have to

be granted, one of them in Arc's own settings where nothing will prompt you

for it. Until both are granted, the server starts normally and then every

tool fails. This is by far the most likely reason a fresh install looks

broken: read

the two macOS permissions, the next section.

package.json declares "os": ["darwin"], so on Linux or Windows the install stops with EBADPLATFORM instead of succeeding and then failing at the first Apple Event. Environment variables go in an env object alongside args; see environment variables.

Claude Code

claude mcp add arc --scope user -- npx -y arc-control-mcp@latest

The -- is required. Without it, claude mcp add reads the -y as one of its own flags and registers the wrong command. Then check what was registered:

claude mcp get arc

Claude Desktop

Edit ~/Library/Application Support/Claude/claudedesktopconfig.json and add the mcpServers block above, merging it with any servers already listed. Quit and reopen Claude Desktop: the file is only read at launch.

Cursor

Add the same mcpServers block to ~/.cursor/mcp.json for every project, or to .cursor/mcp.json for one project.

VS Code

VS Code uses servers, not mcpServers, in .vscode/mcp.json for a workspace or in the file opened by the MCP: Open User Configuration command:

{
  "servers": {
    "arc": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "arc-control-mcp@latest"]
    }
  }
}

Or from the command line:

Shortened. The full README is on GitHub.