> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rewind.rest/llms.txt
> Use this file to discover all available pages before exploring further.

# Connect via local stdio

> Run the Rewind MCP server as a local child process for Claude Desktop and Claude Code, communicating over stdin and stdout.

Local mode runs the `rewind-mcp-server` package on your own machine. Your MCP client launches it as a child process with `npx`, and the two talk over stdin and stdout using JSON-RPC. Your API key stays in the client config file on your machine and is never sent anywhere except the Rewind API.

This is the right choice for desktop clients you control: [Claude Desktop](#claude-desktop) and the [Claude Code CLI](#claude-code-cli). If you are on mobile, on the web, or want a hosted endpoint instead, use [remote connection](/mcp/connect-remote).

## Prerequisites

You need two things before you connect:

* **Node.js**: the server is published to npm as `rewind-mcp-server` and runs with `npx`, so most clients invoke `npx -y rewind-mcp-server` to download and run the latest version on demand.
* **A [Rewind API key](/authentication)**: a read key (prefixed `rw_live_`) is enough, since the server only ever makes GET requests.

## Claude Desktop

Add Rewind to your `mcpServers` config. Use a real key in place of the placeholder, then restart the app.

```json claude_desktop_config.json theme={null}
{
  "mcpServers": {
    "rewind": {
      "command": "npx",
      "args": ["-y", "rewind-mcp-server"],
      "env": {
        "REWIND_API_KEY": "rw_live_..."
      }
    }
  }
}
```

After saving, restart Claude Desktop so it picks up the new server. The client launches the process on startup and tears it down on exit.

## Claude Code CLI

The fastest way to add Rewind in [Claude Code](https://docs.claude.com/en/docs/claude-code) is one command. Everything after `--` is the command the CLI runs to start the server.

```bash theme={null}
claude mcp add rewind -- npx -y rewind-mcp-server
```

Set your key as an environment variable so the spawned process inherits it, or pass it inline with the `--env` flag:

```bash theme={null}
claude mcp add rewind --env REWIND_API_KEY=rw_live_... -- npx -y rewind-mcp-server
```

### Project config with .mcp.json

To share the connection with everyone who works in a repository, commit a `.mcp.json` file to the project root instead. Claude Code reads it automatically when you open the project.

```json .mcp.json theme={null}
{
  "mcpServers": {
    "rewind": {
      "command": "npx",
      "args": ["-y", "rewind-mcp-server"],
      "env": {
        "REWIND_API_KEY": "rw_live_..."
      }
    }
  }
}
```

<Note>
  Treat `.mcp.json` like any other file that may contain secrets. If you commit
  it to a shared repository, reference an environment variable rather than
  pasting a live key, or keep the key in your shell environment and omit the
  `env` block.
</Note>

## Environment variables

The server reads its configuration from two environment variables.

| Variable         | Required | Default                   | Description                                                             |
| ---------------- | -------- | ------------------------- | ----------------------------------------------------------------------- |
| `REWIND_API_KEY` | Yes      | none                      | Your Rewind API key. The server exits at startup if it is missing.      |
| `REWIND_API_URL` | No       | `https://api.rewind.rest` | Base URL for the Rewind API. Override only for self-hosting or testing. |

You almost never need to set `REWIND_API_URL`. Leave it unset to point at the production API. Set it only if you run your own Rewind instance.