MCP server that lets Claude make phone calls
Claude Code, Codex and Cursor can plan a phone call and write what to say, but they cannot place the call. For people who would rather ask than write code, and for AI agents that need to make a phone call as one step of a larger job: Wixzel Voice ships an official Model Context Protocol server, wixzel-voice-mcp, that puts the whole API in front of Claude, Cursor or any MCP client as tools. Connect it once with OAuth, and "call this number and confirm the delivery slot" becomes something an agent can do, over your own SIP trunk, from your prepaid balance, and never without asking before it dials.
Last updated
How do you build an AI agent that makes phone calls over MCP with Wixzel Voice?
- 01claude mcp add --transport http wixzel-voice https://mcp.voice.wixzel.com/mcp
The hosted server, for Claude Code, claude.ai, Claude Desktop and any client that speaks MCP over HTTP. Sign in with OAuth, tick the scopes the client may use, and it is connected. No key is pasted anywhere.
- 02npx -y wixzel-voice-mcp
The same server run locally over stdio with an API key in the environment, for Claude Code, Codex, Cursor, offline work, or pointing at a self-hosted server.
- 03/mcp__wixzel-voice__quickstart
A prompt the server ships: it connects a carrier, registers a number, builds an agent and places a first call, stopping before anything that dials. diagnose_call explains a failed call from its record, usage and SIP logs; spend_report turns a period into dollars by component and by call.
- 04place_call, start_campaign, create_topup, purchase_phone_number
The tools that spend money or ring a real phone are annotated so the client asks before running them. purchase_phone_number buys a number on your own carrier account, which your carrier bills. place_call, create_topup and purchase_phone_number carry an idempotency key, and a retry is safe only when the client passes the same idempotency_key again, which the tool description asks it to do. start_campaign takes none: starting a stopped campaign dials every lead again.
- 05AI clients, in the console
Every connected client is listed with its scopes. Disconnect one and its key stops working immediately.
Which voice engine fits a phone call placed by Claude or another MCP client?
Use the classic engine on Wixzel Voice, at $0.0865 per connected minute. The quickstart prompt builds its first agent on the default engine, which is the cheapest reliable pairing for English. An agent can ask for sarvam for Indian languages or gemini-live for the lowest latency; the engines are listed by a tool, so it never has to guess a model name.
What does a phone call placed by Claude or another MCP client cost on Wixzel Voice?
Wixzel Voice engine time for 3-minute calls on the classic engine, at typical speech rates, billed per second of actual usage. Telephony is your own trunk at your carrier’s rate and is not included, and shorter calls cost proportionally less.
| Calls per month | Connected minutes | Engine cost per month |
|---|---|---|
| 100 | 300 | $25.95 |
| 500 | 1,500 | $130 |
| 2,000 | 6,000 | $519 |
Prepaid: add credit from $5 and the calls spend it. Estimate your own mix.
Which guides show how to build an AI agent that makes phone calls over MCP on Wixzel Voice?
Connect the Wixzel Voice MCP server to Claude Code or claude.ai, and Claude can build a voice agent, place a call over your own SIP trunk and read you the transcript.
Four requests to a ringing phone, what a call record returns, and what a call costs.
Twilio, Telnyx, Plivo, Vonage, Bandwidth, Exotel, Vobiz, Mobily or any SIP provider: what to set at the carrier.
Frequently asked questions
Can Claude make phone calls with Wixzel Voice?
claude mcp add --transport http wixzel-voice https://mcp.voice.wixzel.com/mcp in Claude Code, sign in, and Claude can create an agent, place a call over your SIP trunk, wait for it to finish and read the transcript. The tool that dials asks for confirmation first.Which AI clients work with the MCP server?
Does the AI agent get my API key?
Can an AI agent spend my money without asking?
What does a call placed from Claude cost?
Does the MCP server work with a self-hosted server?
Do I still need a SIP trunk?
What else do agencies and developers build on Wixzel Voice?
Build an agent that answers the phone, checks availability and books an appointment, over your own SIP trunk, with the booking written back through the API.
Upload leads, start a campaign, and have an agent call each one over your own SIP trunk and ask your qualifying questions. Every call is a record with its status and transcript, linked to the lead.
Answer a support number with an agent that reads from a knowledge base you upload, handles the common questions, and leaves a transcript of every call.
Run phone agents in Indian languages on models built for them, with the sarvam engine covering speech-to-text, the language model and text-to-speech end to end.
Put an agent in a browser page, a Flutter app or a kiosk with no SIP trunk and no phone number: your server mints a one-minute session, the app streams audio over a WebSocket, and the session is billed like a call.
Put a talking AI assistant on your website with one script tag: an agent made from your site, with an animated mascot visitors call from the browser, caller details, who-can-call settings and daily caps.
Run AI phone calls for a few cents a minute: per-second billing from prepaid credit, no subscription or minimum, your own SIP trunk with no telephony markup, and every charge itemised.
Give a voice agent a face: an animated avatar that lip-syncs to the agent, for a website, a share link, a web app or a Flutter app, with no fee for the avatar.
Build a phone agent for each client on their own account and carrier, in their language, and charge a retainer on a cost billed per second.
Operator, prices, limits, refunds and data location, on one page.
Build your first voice agent