VOICEVOX MCP server

This MCP server interfaces with the VOICEVOX engine for speech synthesis and speaker information retrieval. It's implemented in TypeScript using the MCP SDK, enabling you to generate speech from text and access speaker data through a standardized protocol.

Installation

Setting Up the VOICEVOX Engine

First, start the VOICEVOX engine using Docker (recommended):

docker compose up -d

This will launch the VOICEVOX engine on localhost:50021.

Installing and Building the MCP Server

Install dependencies and build the server:

npm install
npm run build

Configuration and Usage

Setting Up in Cursor

Create a configuration file at .cursor/mcp.json:

{
  "mcpServers": {
    "voicevox-mcp": {
      "command": "node",
      "args": ["${Path to Repository}/dist/index.js"],
      "env": {
        "SPEAKER_ID": 8,
        "SPEED_SCALE": 1.2,
        "VOICEVOX_API_URL": "http://localhost:50021" 
      }
    }
  }
}

You can customize the VOICEVOX_API_URL if your engine is running at a different location.

Available Tools

The server provides two main tools:

• speakers: Retrieves a list of available speakers from the VOICEVOX engine
• speak: Synthesizes text to speech using the specified speaker and plays it locally

Environment Variables

You can configure the server using these environment variables:

• SPEAKER_ID: The default speaker ID to use for synthesis (default: 8)
• SPEED_SCALE: The playback speed multiplier (default: 1.2)
• VOICEVOX_API_URL: The URL of the VOICEVOX engine API (default: http://localhost:50021)

Requirements and Limitations

• The VOICEVOX engine must be running at localhost:50021 (or your configured URL)
• Local audio playback currently uses the afplay command, which is only available on macOS

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "voicevox-mcp" '{"command":"node","args":["${Path to Repository}/dist/index.js"],"env":{"SPEAKER_ID":8,"SPEED_SCALE":1.2,"VOICEVOX_API_URL":"http://localhost:50021"}}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "voicevox-mcp": {
            "command": "node",
            "args": [
                "${Path to Repository}/dist/index.js"
            ],
            "env": {
                "SPEAKER_ID": 8,
                "SPEED_SCALE": 1.2,
                "VOICEVOX_API_URL": "http://localhost:50021"
            }
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "voicevox-mcp": {
            "command": "node",
            "args": [
                "${Path to Repository}/dist/index.js"
            ],
            "env": {
                "SPEAKER_ID": 8,
                "SPEED_SCALE": 1.2,
                "VOICEVOX_API_URL": "http://localhost:50021"
            }
        }
    }
}

3. Restart Claude Desktop for the changes to take effect