MCP Tts Voicevox MCP Server

The voicevox_speak_player tool uses MCP Apps to render an interactive audio player directly inside the chat. The mcp tts voicevox mcp server wraps that behind the Model Context Protocol, so an assistant can use it through 13 defined tools rather than through you.

What it actually does

The voicevox_speak_player tool uses MCP Apps to render an interactive audio player directly inside the chat. Unlike the standard voicevox_speak tool which plays audio on the server, audio is played on the client side (in the browser/app) — no audio device needed on the server.

• Client-side playback — — Audio plays in Claude Desktop's chat, not on the server. Works even over remote connections
• Play/Pause controls — — Full playback controls embedded in the conversation
• Multi-speaker dialogue — — Sequential playback of multiple speakers in one player with track navigation
• Speaker switching — — Change the voice of any segment directly from the player UI
• Segment editing — — Adjust speed, volume, intonation, pause length, and pre/post silence per segment
• Accent phrase editing — — Edit accent positions and mora pitch directly in the UI

Its toolset

Everything the assistant can do here goes through one of these:

• speak_player — Create a new player session and display the UI. Returns viewUUID
• resynthesize_player — Update all segments for an existing player (new viewUUID each call)
• get_player_state — Read the current player state (paginated) for AI tuning
• open_dictionary_ui — Open the user dictionary manager UI
• Group — Tools
• player — speak_player, resynthesize_player, get_player_state, open_dictionary_ui
• dictionary — get_accent_phrases, get_user_dictionary, add_user_dictionary_word, update_user_dictionary_word, delete_user_dictionary_word
• file — synthesize_file
• apps — speak_player, resynthesize_player, open_dictionary_ui (MCP App UI tools)
• Features — Export behavior by environment: - Save and open always exports WAV files. If opening the file explorer is not supported, export still succeeds and
• Requirements — The Requirements tool exposed by this server
• Setup — The Setup tool exposed by this server

Adding it to your client

Installation goes through your MCP client rather than a global install: point it at @kajidog/mcp-tts-voicevox on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.

Configuration

You will need 5 environment variables: VOICEVOX_DISABLED_TOOLS, VOICEVOX_DISABLED_GROUPS, VOICEVOX_URL, MCP_HTTP_HOST, MCP_API_KEY. The server will not start without them, which is usually why the tools fail to appear on a first run. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

• Node.js 20.0.0 or higher (or Bun) or Docker - VOICEVOX Engine (must be running; included in Docker Compose) - ffplay (optional, recommended — not needed with Docker)

When to reach for it

Plenty of browser automation servers cover similar ground. The differences that matter in practice are scope of access and how much setup stands between you and a working tool call. MCP Tts Voicevox's toolset — speak_player, resynthesize_player, get_player_state and 10 more — is a fair guide to whether it matches your workflow. It is maintained by kajidog; worth a glance at recent repository activity before you build anything load-bearing on it.

SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.

Caveats

• It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
• With 13 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch MCP Tts Voicevox.
• Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
• MCP clients confirm each tool call by default. Leave that on until you have watched what the mcp tts voicevox mcp server does with a few real requests.