JustCall MCP Server

The JustCall Model Context Protocol (MCP) Server lets Large Language Models (LLMs) and AI agents make real-world voice calls and send SMS directly through JustCall’s APIs — securely, contextually, and programmatically.

It provides a function-calling interface for conversational AI systems, enabling:

• 📞 AI-powered calling: Let your LLM initiate, manage, or transcribe calls using JustCall.
• 💬 Smart messaging: Allow your AI agent to send or respond to SMS within conversations.
• ⚙️ Seamless integration: Use the MCP standard to connect JustCall’s telephony capabilities with any LLM runtime or orchestration framework.

In short: It gives your LLMs a voice and a phone number — turning chatbots into truly conversational agents.

🧩 Prerequisites

This project requires Node.js (which includes npm and npx).

Installing Node.js

• Visit the official Node.js website: 👉 https://nodejs.org/en/download
• Download and install the LTS (Long-Term Support) version for your platform (Windows, macOS, or Linux).

Claude Desktop Setup

1. Open Claude Desktop and press CMD + , to go to Settings.
2. Click on the Developer tab.
3. Click on the Edit Config button.
4. This will open the claude_desktop_config.json file in your file explorer.
5. Get your JustCall API Key & Secret from the JustCall dashboard (https://app.justcall.io/app/developersApiCredentials).
6. Add the following to your claude_desktop_config.json file. See here for more details.
7. Restart the Claude Desktop after editing the config file.

Remote Configuration

{
  "mcpServers": {
    "JustCall-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "supergateway",
        "--streamableHttp",
        "https://mcp.justcall.host/mcp",
        "--oauth2Bearer",
        "<JUSTCALL_API_KEY>:<JUSTCALL_API_SECRET>"
      ]
    }
  }
}

Remote MCP

To connect to JustCall's MCP server remotely:

Streamable HTTP (Recommended)

The default and recommended way to connect is via Streamable HTTP Transport:

• Connect to https://mcp.justcall.host/mcp from any MCP client using Streamable HTTP Transport
• Include your JustCall API key as a bearer token in the request headers
• Example header: Authorization: <JUSTCALL_API_KEY>:<JUSTCALL_API_SECRET>

Development

# Install dependencies
pnpm install

# Build the server
pnpm run build

# Use inspector to test the server
pnpm run inspector

Update your claude_desktop_config.json to use the mcp server.