mcp-tts

MCP Server for TTS (Text-to-Speech)

What? 🤔

Adds Text-to-Speech to things like Claude Desktop and Cursor IDE.

It registers four TTS tools:

• say_tts
• elevenlabs_tts
• google_tts
• openai_tts

say_tts

Uses the macOS say binary to speak the text with built-in system voices

elevenlabs_tts

Uses the ElevenLabs text-to-speech API to speak the text with premium AI voices

google_tts

Uses Google's Gemini TTS models to speak the text with 30 high-quality voices. Available voices include:

• Zephyr (Bright), Puck (Upbeat), Charon (Informative)
• Kore (Firm), Fenrir (Excitable), Leda (Youthful)
• Orus (Firm), Aoede (Breezy), Callirhoe (Easy-going)
• Autonoe (Bright), Enceladus (Breathy), Iapetus (Clear)
• And 18 more voices with various characteristics

openai_tts

Uses OpenAI's Text-to-Speech API to speak the text with 6 natural-sounding voices:

• coral (Default, warm and natural)
• alloy (Balanced tone)
• echo (Warm and engaging)
• fable (Expressive and storytelling)
• onyx (Deep and resonant)
• nova (Bright and articulate)
• shimmer (Smooth and pleasant)

Supports three quality models:

• gpt-4o-mini-tts - Default, optimized quality and speed
• tts-1 - Standard quality, faster generation
• tts-1-hd - High definition audio, premium quality

Additional features:

• Speed control from 0.25x to 4.0x (default: 1.0x)
• Custom voice instructions (e.g., "Speak in a cheerful and positive tone") via parameter or OPENAI_TTS_INSTRUCTIONS environment variable

Configuration

Suppressing "Speaking:" Output

By default, TTS tools return a message like "Speaking: [text]" when speech completes. This can interfere with LLM responses. To suppress this output:

Environment Variable:

export MCP_TTS_SUPPRESS_SPEAKING_OUTPUT=true

Command Line Flag:

mcp-tts --suppress-speaking-output

When enabled, tools return "Speech completed" instead of echoing the spoken text.

Getting Started

Install

go install github.com/blacktop/mcp-tts@latest

❱ mcp-tts --help

TTS (text-to-speech) MCP Server.

Provides multiple text-to-speech services via MCP protocol:

• say_tts - Uses macOS built-in 'say' command (macOS only)
• elevenlabs_tts - Uses ElevenLabs API for high-quality speech synthesis
• google_tts - Uses Google's Gemini TTS models for natural speech
• openai_tts - Uses OpenAI's TTS API with various voice options

Each tool supports different voices, rates, and configuration options.
Requires appropriate API keys for cloud-based services.

Designed to be used with the MCP (Model Context Protocol).

Usage:
  mcp-tts [flags]

Flags:
  -h, --help                       help for mcp-tts
      --suppress-speaking-output   Suppress 'Speaking:' text output
  -v, --verbose                    Enable verbose debug logging

Set Claude Desktop Config

{
  "mcpServers": {
    "say": {
      "command": "mcp-tts",
      "env": {
        "ELEVENLABS_API_KEY": "********",
        "ELEVENLABS_VOICE_ID": "1SM7GgM6IMuvQlz2BwM3",
        "GOOGLE_AI_API_KEY": "********",
        "OPENAI_API_KEY": "********",
        "OPENAI_TTS_INSTRUCTIONS": "Speak in a cheerful and positive tone",
        "MCP_TTS_SUPPRESS_SPEAKING_OUTPUT": "true"
      }
    }
  }
}

Environment Variables

• ELEVENLABS_API_KEY: Your ElevenLabs API key (required for elevenlabs_tts)
• ELEVENLABS_VOICE_ID: ElevenLabs voice ID (optional, defaults to a built-in voice)
• GOOGLE_AI_API_KEY or GEMINI_API_KEY: Your Google AI API key (required for google_tts)
• OPENAI_API_KEY: Your OpenAI API key (required for openai_tts)
• OPENAI_TTS_INSTRUCTIONS: Custom voice instructions for OpenAI TTS (optional, e.g., "Speak in a cheerful and positive tone")

Test

Test macOS TTS

❱ cat test/say.json | go run main.go --verbose

2025/03/23 22:41:49 INFO Starting MCP server name="Say TTS Service" version=1.0.0
2025/03/23 22:41:49 DEBU Say tool called request="{Request:{Method:tools/call Params:{Meta:<nil>}} Params:{Name:say_tts Arguments:map[text:Hello, world!] Meta:<nil>}}"
2025/03/23 22:41:49 DEBU Executing say command args="[--rate 200 Hello, world!]"
2025/03/23 22:41:49 INFO Speaking text text="Hello, world!"

{"jsonrpc":"2.0","id":3,"result":{"content":[{"type":"text","text":"Speaking: Hello, world!"}]}}

Test Google TTS

❱ cat test/google_tts.json | go run main.go --verbose

2025/05/23 18:26:45 INFO Starting MCP server name="Say TTS Service" version=""
2025/05/23 18:26:45 DEBU Google TTS tool called request="{...}"
2025/05/23 18:26:45 DEBU Generating TTS audio model=gemini-2.5-flash-preview-tts voice=Kore text="Hello! This is a test of Google's TTS API. How does it sound?"
2025/05/23 18:26:49 INFO Playing TTS audio via beep speaker bytes=181006
2025/05/23 18:26:53 INFO Speaking via Google TTS text="Hello! This is a test of Google's TTS API. How does it sound?" voice=Kore

{"jsonrpc":"2.0","id":4,"result":{"content":[{"type":"text","text":"Speaking: Hello! This is a test of Google's TTS API. How does it sound? (via Google TTS with voice Kore)"}]}}

Test OpenAI TTS

❱ cat test/openai_tts.json | go run main.go --verbose

2025/05/23 19:15:32 INFO Starting MCP server name="Say TTS Service" version=""
2025/05/23 19:15:32 DEBU OpenAI TTS tool called request="{...}"
2025/05/23 19:15:32 DEBU Generating OpenAI TTS audio model=tts-1 voice=nova speed=1.2 text="Hello! This is a test of OpenAI's text-to-speech API. I'm using the nova voice at 1.2x speed."
2025/05/23 19:15:34 DEBU Decoding MP3 stream from OpenAI
2025/05/23 19:15:34 DEBU Initializing speaker for OpenAI TTS sampleRate=22050
2025/05/23 19:15:36 INFO Speaking text via OpenAI TTS text="Hello! This is a test of OpenAI's text-to-speech API. I'm using the nova voice at 1.2x speed." voice=nova model=tts-1 speed=1.2

{"jsonrpc":"2.0","id":5,"result":{"content":[{"type":"text","text":"Speaking: Hello! This is a test of OpenAI's text-to-speech API. I'm using the nova voice at 1.2x speed. (via OpenAI TTS with voice nova)"}]}}

License

MIT Copyright (c) 2025 blacktop