mcp-tts

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:

Achernar, Achird, Algenib, Algieba, Alnilam, Aoede, Autonoe, Callirrhoe, Charon, Despina, Enceladus, Erinome, Fenrir, Gacrux, Iapetus, Kore, Laomedeia, Leda, Orus, Puck, Pulcherrima, Rasalgethi, Sadachbia, Sadaltager, Schedar, Sulafat, Umbriel, Vindemiatrix, Zephyr, Zubenelgenubi

openai_tts

Uses OpenAI's Text-to-Speech API to speak the text with 10 natural-sounding voices:

• alloy (Warm, conversational, modern)
• ash (Confident, assertive, slightly textured)
• ballad (Gentle, melodious, slightly lyrical)
• coral (Cheerful, fresh, upbeat)
• echo (Neutral, calm, balanced)
• fable (Storyteller-like, expressive)
• nova (Clear, precise, slightly formal)
• onyx (Deep, authoritative, resonant)
• sage (Soothing, empathetic, reassuring)
• shimmer (Bright, animated, playful)
• verse (Versatile, expressive)

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

Sequential vs Concurrent TTS

By default, the TTS server enforces sequential speech operations - only one TTS request can play audio at a time. This prevents multiple agents from speaking simultaneously and creating an unintelligible cacophony. Subsequent requests will wait in a queue until the current speech completes.

Multi-Instance Protection: The mutex works both within a single MCP server process and across multiple Claude Desktop instances. When running multiple Claude Desktop terminals, they coordinate via a system-wide file lock to prevent overlapping speech.

To allow concurrent TTS operations (multiple speeches playing simultaneously):

Environment Variable:

export MCP_TTS_ALLOW_CONCURRENT=true

Command Line Flag:

mcp-tts --sequential-tts=false

Note: Concurrent TTS may result in overlapping audio that's difficult to understand. Use this option only when you explicitly want multiple TTS operations to run simultaneously.

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.

Saving Audio to Disk

Save TTS audio output to files instead of (or in addition to) playing them:

Environment Variables:

export MCP_TTS_OUTPUT_DIR=/path/to/audio    # Save audio files to this directory
export MCP_TTS_NO_PLAY=true                  # Skip playback, only save (optional)

Command Line Flags:

mcp-tts --output-dir /path/to/audio          # Save and play
mcp-tts --output-dir /path/to/audio --no-play  # Save only, no playback

Files are saved with unique names: tts_{timestamp}_{hash}.{ext}