# MCP Bridge CLI — connect Pieces to your AI tools

The Pieces MCP Bridge CLI is a small helper that connects MCP clients to PiecesOS. Learn what it does, and what to do if you opened it from the Windows Start menu.

## Pieces MCP Bridge

The `MCP` Bridge is a small command-line helper that connects an MCP client to the local `PiecesOS` service. It runs in the background and does not have its own interface.

## Opened this from the Start menu?

You do not need to launch this. Connect `MCP` clients through the Pieces Desktop app instead.

On some Windows installs, the Bridge appears as an app next to `PiecesOS`. Windows requires the Bridge to be registered as its own app entry, which is why you are seeing it here. It is normally started by another application, not opened by hand.

Launching it this way does not start anything you need. If a console window is open, you can close it. Nothing is broken, and there is nothing to keep running from the Start menu.

Do not uninstall the Bridge entry on its own. Removing it uninstalls `PiecesOS` as well.

## Connect a client instead

1. Confirm `PiecesOS` is running and **LTM-2 Engine** is enabled in its Quick Menu.
2. In Pieces Desktop, open **Settings → MCP → MCP Connections**.
3. Connect the client you want from that list, then restart the client.

Pieces Desktop handles this setup automatically for supported clients.

## What the Bridge does

`PiecesOS` runs the Pieces `MCP` server and serves it over a local endpoint on your own machine, on port `39300` by default. Many MCP clients cannot open an endpoint like that directly: they expect to launch a command and talk to it over `stdio`. The Bridge is that command. A client starts it, and it relays the conversation to `PiecesOS`.

Shipping the Bridge alongside `PiecesOS` is what makes one-click connections work. Supported clients connect without you installing Node.js or a third-party helper first.

- Starts when a configured MCP client needs to connect.
- Routes that connection to the MCP server running in `PiecesOS`.
- Stops when the client closes the connection.

### What it does not do

- It has no window, settings, or sign-in of its own.
- It does not store your memories. `PiecesOS` keeps that data on your device.
- It does not connect anywhere you have not configured, which by default is `PiecesOS` on your own machine.
- It does not need to be running when you are not using an MCP client.

## Want to learn more about MCP?

`MCP` is an open standard for giving AI tools context from outside their own window. Pieces uses it to expose your `Long-Term Memory Engine` to any compatible client, so Cursor, VS Code, or Claude can answer questions about work you have already done.

[See what Pieces MCP does](/mcp)

[Read the MCP setup guide](https://docs.pieces.app/products/mcp)