Connecting an Assistant

An AI app on the same computer as the desktop app starts the Trusted Codes MCP server by itself and talks to it over a pipe. Nothing is opened to the network. Assistants in a browser cannot connect; Assistants in a Browser explains why.

A later version of the desktop app connects Claude Desktop with one button. Until then, the steps on this page use the Terminal.

Before You Start

• Install the desktop app and sign in once.
• On a Mac, the app must be in the Applications folder. A copy that runs from the downloaded disk image or from the Downloads folder writes a path that stops working.
• On Windows and Linux, a later version of the app connects for you. The commands on this page are for the Mac.

Claude Desktop (Mac)

1. Quit Claude Desktop completely (⌘Q).

2. Open the Terminal and run:

   "/Applications/Trusted Codes.app/Contents/MacOS/tcc-desktop" mcp configure claude-desktop

3. Open Claude Desktop again.

Cursor (Mac)

1. Quit Cursor completely (⌘Q).

2. Open the Terminal and run:

   "/Applications/Trusted Codes.app/Contents/MacOS/tcc-desktop" mcp configure cursor

3. Open Cursor again.

Claude Code (Mac)

Open the Terminal and run:

claude mcp add --scope user trusted-codes -- "/Applications/Trusted Codes.app/Contents/MacOS/tcc-desktop" mcp

Then start a new Claude Code session. Do not use mcp configure claude-code: the current version writes a file that Claude Code does not read.

What the Command Writes

mcp configure adds an entry called trusted-codes to the AI app’s settings file:

• Claude Desktop: ~/Library/Application Support/Claude/claude_desktop_config.json
• Cursor: ~/.cursor/mcp.json

{
  "mcpServers": {
    "trusted-codes": {
      "command": "/Applications/Trusted Codes.app/Contents/MacOS/tcc-desktop",
      "args": ["mcp"]
    }
  }
}

The other entries in the file stay, with one exception in the current version: if the file cannot be read, for example after a hand edit with a typing error, the command replaces it with a file that holds only the Trusted Codes entry. If you edited the file by hand, make a copy of it first.

Checking and Removing

"/Applications/Trusted Codes.app/Contents/MacOS/tcc-desktop" mcp status
"/Applications/Trusted Codes.app/Contents/MacOS/tcc-desktop" mcp remove cursor

status shows whether Claude Desktop and Cursor have a trusted-codes entry. For Claude Code, run claude mcp list. After remove, quit the AI app and open it again.

How the Connection Works

The AI app launches the desktop app’s binary as a child process and talks JSON-RPC to it over standard input and output. This is the only way an assistant reaches Trusted Codes, and it is also the only way on which the provider-stamp tool is available — that tool signs with the key on that machine.

Startup is deliberately instant — no keychain prompt, no network call, no browser. Nothing is checked until the assistant calls its first tool. If you are not signed in, that call comes back as AUTH_REQUIRED, the assistant calls the login tool, a browser opens, and it retries. On a new device login can answer recovery_required instead, and the assistant will ask you for the three recovery words from the mobile app.

If Your Plan Does Not Include It

mcp configure checks your account before it writes anything, and tells you if the MCP server is not part of your plan. The check is a courtesy, made where a person is waiting for an answer — it is not a lock. The server runs on your machine against a key you already hold and computes codes offline, so no server is in a position to refuse it.