cancel-my-sub-mcp

Give your coding agent a phone. Cancel subs, dispute charges, and negotiate bills via real phone calls from inside Claude Code, Cursor, Windsurf, Zed, ChatGPT desktop, or any MCP client.

Built at the Call My Agent Hackathon (May 2026), YC SF.

Install

Add this MCP server to your client config:

{
  "mcpServers": {
    "cancel-my-sub": {
      "command": "npx",
      "args": ["-y", "cancel-my-sub-mcp"],
      "env": {
        "AGENTPHONE_API_KEY": "ap_..."
      }
    }
  }
}

For local development from this checkout:

{
  "mcpServers": {
    "cancel-my-sub": {
      "command": "node",
      "args": ["/Users/t3rni/agentphone/dist/index.js"],
      "env": {
        "AGENTPHONE_API_KEY": "ap_..."
      }
    }
  }
}

Demo Prompts

• "Cancel my Planet Fitness membership. Account is under my email."
• "Dispute the $45 overage on last month's Comcast bill."
• "Call AT&T and negotiate my plan down to $50/mo. Verizon offered me that."

Tools

cancel_subscription

Places a real call to cancel a subscription. The voice agent navigates IVR, asks for a human representative, declines retention offers by default, and tries to obtain a confirmation number.

dispute_charge

Places a real call to dispute a charge. The voice agent explains the disputed charge, asks for a refund or credit, and escalates when the first representative cannot help.

negotiate_bill

Places a real call to negotiate down a recurring bill. The voice agent asks for loyalty or retention pricing, mentions competitor offers when supplied, and asks for a supervisor if needed.

How It Works

flowchart LR
  A[MCP client] --> B[cancel-my-sub-mcp]
  B --> C[AgentPhone TypeScript SDK]
  C --> D[AgentPhone REST API]
  D --> E[Real phone call]
  E --> F[Live transcript SSE]
  F --> B
  B --> G[MCP progress notifications]
  B --> H[Final transcript and outcome]

The server uses stdio transport only. There is no UI, webhook server, account system, or persistence layer.

AgentPhone Integration Notes

This package was wired against the installed agentphone SDK, not guessed API names:

• Constructor: new AgentPhoneClient({ token: process.env.AGENTPHONE_API_KEY })
• Agent creation: client.agents.createAgent({ voiceMode: "hosted", systemPrompt, ... })
• Number provisioning: client.numbers.createNumber({ agentId })
• Number reuse: client.numbers.listNumbers(...), then client.agents.attachNumberToAgent(...)
• Outbound calls: client.calls.createOutboundCall({ agentId, toNumber, fromNumberId, initialGreeting, systemPrompt })
• Completion: live transcript SSE when available, then client.calls.getCall(...) polling
• Transcript fallback: client.calls.getCallTranscript(...) or transcript data on getCall(...)

Optional environment variables:

• AGENTPHONE_NUMBER_ID: reuse a specific number as caller ID.
• AGENTPHONE_NUMBER_COUNTRY: country for first-time number provisioning. Defaults to US.
• AGENTPHONE_AREA_CODE: preferred area code for first-time number provisioning.

Development

npm install
npm test
npm run build

Run locally:

AGENTPHONE_API_KEY=ap_... npm run dev

Stage Demo Plan

1. Open Claude Code and show the MCP config JSON.
2. Ask Claude to cancel a low-stakes subscription or call a test phone.
3. Claude invokes cancel_subscription.
4. Transcript turns stream back as MCP progress notifications.
5. The call ends and Claude reports the outcome, transcript, duration, and any confirmation number.

Have a pre-recorded backup, but try the live call first.