JustCall

The JustCall MCP Server connects Large Language Models to real-world telephony through the Model Context Protocol.

This MCP server enables your AI agents to make phone calls, send text messages, and manage communications directly through JustCall’s telephony infrastructure.

Features

• 📞 Voice call management and transcription
• 💬 SMS messaging with contact management
• 👥 User and agent coordination
• 📊 Comprehensive analytics and reporting
• 🔔 Real-time webhook notifications
• 📱 Phone number administration
• 📢 Sales dialer campaign automation

Use Cases

• Automated Customer Outreach: You could build an AI agent that pulls a list of new leads from your CRM each morning. The agent then uses the send_sms tool to send a personalized introductory message to each one. This takes a manual, repetitive task off your sales team’s plate.
• Intelligent Appointment Schedulers: An AI can manage appointment reminders. It can check a calendar, find upcoming appointments, and use the send_sms function to text a confirmation reminder. It can then use check_sms_reply to see if the person confirmed, canceled, or wants to reschedule, all without human intervention.
• Dynamic Voice Support Menus: Instead of a static “Press 1 for sales” phone menu, you can have an LLM-powered agent that actually talks to the customer. It can use tools like get_user to look up customer information and get_call_journey to understand past interactions before deciding how to route the call.

How to Use It

Claude Desktop Setup

To get this running with Claude Desktop, you’ll need to edit its configuration file.

Open the Claude Desktop settings by pressing CMD + , (on Mac). Navigate to the Developer tab and click Edit Config. This action opens the claude_desktop_config.json file.

You will need your JustCall API Key and Secret. You can find these in your JustCall developer dashboard.

Add the following JSON block to your claude_desktop_config.json file. This tells Claude Desktop how to find and run the JustCall MCP server.

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

Remember to replace <JUSTCALL_API_KEY>:<JUSTCALL_API_SECRET> with your actual credentials. After you save the file, restart Claude Desktop for the changes to take effect.

Remote MCP Connection

If you want to connect from a different MCP client, you can use the Streamable HTTP Transport. This is the recommended method.

Your client should connect to https://mcp.justcall.host/mcp. You must include your JustCall API key and secret as a bearer token in the Authorization header.

The header format looks like this: Authorization: <JUSTCALL_API_KEY>:<JUSTCALL_API_SECRET>

Available Tools

The server comes with 29 tools:

• Calls (5 tools): list_calls, get_call, update_call, get_call_journey, get_voice_agent_data.
• Users & Agents (2 tools): list_users, get_user.
• SMS & Messaging (8 tools): send_sms, list_sms, get_sms, check_sms_reply, list_sms_tags, get_sms_tag, create_sms_tag, delete_sms_tag.
• Contacts (2 tools): list_contacts, create_contact.
• Analytics (4 tools): get_agent_analytics, get_account_analytics, get_number_analytics, get_sales_dialer_analytics.
• Webhooks (2 tools): list_webhooks, create_webhook.
• Phone Numbers (2 tools): list_numbers, get_number.
• Sales Dialer Campaigns (4 tools): list_campaigns, get_campaign, create_campaign, update_campaign.

Development

If you want to work on the server code itself, you can clone the project.

Install the dependencies.

pnpm install

Build the server.

pnpm run build

Test the server with the inspector tool.

pnpm run inspector

You would then update your claude_desktop_config.json to point to your local development server instead of the remote one.

FAQs

Q: What is the difference between the remote configuration and running it locally?
A: The remote configuration points to JustCall’s hosted MCP server (https://mcp.justcall.host/mcp), which is ready to use immediately. Running it locally is for development purposes.

Q: How does authentication work?
A: Authentication uses your JustCall API Key and Secret. You combine them into a single string separated by a colon (KEY:SECRET) and pass them as a bearer token in the Authorization header of your requests.

Q: Do I need a paid JustCall account?
A: Yes, you need an active JustCall account to generate the API credentials required to authenticate with the MCP server. The server’s functions interact directly with your JustCall account’s data and services.