MCP connector - Hopper

Hopper’s MCP server gives an AI app Hopper’s voice and tools: it can speak, transcribe, look up models and prices, return tested integration code, and review a voice agent for latency. Speech, transcription and the lookup tools need no account.

https://withhopper.com/mcp

Streamable HTTP. Sign-in, when a tool needs it, is OAuth with your Hopper account.

Add it

claude mcp add --transport http hopper https://withhopper.com/mcp

codex mcp add hopper --url https://withhopper.com/mcp

{
  "mcpServers": {
    "hopper": { "url": "https://withhopper.com/mcp" }
  }
}

Claude (claude.ai and the desktop app): Settings → Connectors → Add custom connector, then paste the URL.
ChatGPT: turn on Developer mode in Settings → Security and login, then add the URL at chatgpt.com/plugins → +.
Coding agents: the Hopper plugin adds this connector plus skills that set Hopper up in a voice-agent project and benchmark it. In Claude Code: claude plugin marketplace add https://withhopper.com/marketplace.json, then claude plugin install hopper@hopper.

Tools

Tool	Sign-in	What it does
`speak`	No	Text to speech, `text` and optional `voice`. Returns 24 kHz mono WAV and a playable link (10 minutes, 3 plays); ChatGPT and other MCP Apps hosts show an audio player
`transcribe`	No	English speech to text with word timestamps, up to 5 minutes per call. WAV, MP3, M4A, Ogg/Opus, FLAC or WebM: a file attached in ChatGPT (`audio_file`), `audio_url` (public https, up to 25 MB) or `audio_base64` (up to 3 MB)
`list_voices`	No	Voices ready for speech: id, name, language, gender, description
`list_models`	No	Models, context length, prices and availability, as the API bills them
`get_integration_guide`	No	Tested code that switches a voice agent’s LLM to Hopper. `framework`: `livekit`, `pipecat`, `vapi` or `openai-sdk`
`review_voice_agent_config`	No	Checks a `system_prompt`, optional `tools` and `client_code` for what delays the first token, with fixes
`get_account`	Yes	Credits, spend, request and token counts, and API keys (names and first characters only)
`create_api_key`	Yes	Creates a key on your account, optional `name`, and returns a one-time link to copy it in the console. The key never appears in the chat

ChatGPT, not signed in: each ChatGPT user gets their own allowance for speech and transcription. Near its limit the tools say so; at the limit, ChatGPT offers to connect a Hopper account. The daily limits below also apply.
Other apps, not signed in: speech and transcription work under shared limits: 10 calls a minute, about a minute of speech per call, and 10 minutes of speech and 30 minutes of transcription a day.
Signed in: speech and transcription bill your own credits; new accounts start with free credit (see Models).

Signing in asks for these scopes: account:read (get_account), keys:write (create_api_key) and audio (speech and transcription on your credits). Your app opens Hopper’s sign-in page the first time a tool needs one.

What it doesn’t do

The connector can’t change account settings, delete or reveal existing keys, or buy credits; those are in the console. It doesn’t call the LLM: use the API for completions.

Data

The connector receives the arguments of the tool you call. Text you speak and audio you transcribe aren’t stored. See the privacy policy.

​Add it

​Tools

​Free use and sign-in

​What it doesn’t do

​Data

Add it

Tools

Free use and sign-in

What it doesn’t do

Data