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.

Claude Desktop Setup

1. Open Claude Desktop and press CMD + , to go to Settings.
2. Click on the Connectors tab.
3. Click on the Add Custom Connector button.
4. Add name as JustCall and Remote Server Url as https://mcp.justcall.host/mcp.
5. Now on JustCall from the Connectors list click on Connect button for JustCall.
6. It will open a JustCall page requesting API key and secret.
7. Get your JustCall API Key & Secret from the JustCall dashboard (https://app.justcall.io/app/developersApiCredentials).
8. Enter the API key and Secret and press Continue, it should redirect back you to Claude.

Claude Web - https://claude.ai

1. Open connectors url in your Browser - https://claude.ai/settings/connectors.
2. Click on the Connectors tab.
3. Click on the Add Custom Connector button.
4. Add name as JustCall and Remote Server Url as https://mcp.justcall.host/mcp.
5. Now on JustCall from the Connectors list click on Connect button for JustCall.
6. It will open a JustCall page requesting API key and secret.
7. Get your JustCall API Key & Secret from the JustCall dashboard (https://app.justcall.io/app/developersApiCredentials).
8. Enter the API key and Secret and press Continue, it should redirect back you to Claude.

Chat GPT (Only available on Plus, Pro, Business and Enterprise)

1. Open connectors url in your Browser - https://chatgpt.com/#settings/Connectors.
2. Click on the Apps & Connectors tab.
3. Ensure developer mode is enabled in advanced settings
4. Click on the Create button.
5. Add name as JustCall and MCP Server Url as https://mcp.justcall.host/mcp. You can skip other fields.
6. Now on JustCall from the Connectors list click on Connect button for JustCall.
7. It will open a JustCall page requesting API key and secret.
8. Get your JustCall API Key & Secret from the JustCall dashboard (https://app.justcall.io/app/developersApiCredentials).
9. Enter the API key and Secret and press Continue, it should redirect back you to Chat GPT.

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: Bearer <JUSTCALL_API_KEY>:<JUSTCALL_API_SECRET>

Authentication & Security

The JustCall MCP Server implements OAuth2 authentication for secure access to all endpoints.

OAuth2 Configuration

The server supports OAuth2 authorization with the following features:

• Authorization Endpoint: OAuth2 authorization server metadata is available at /.well-known/oauth-authorization-server
• Grant Type: Authorization code flow with PKCE (Proof Key for Code Exchange)
• Code Challenge Method: S256 (SHA-256)
• Token Authentication: All MCP and SSE endpoints require Bearer token authentication

Protected Endpoints

The following endpoints require valid Bearer token authentication:

• /mcp - Main MCP endpoint
• /sse - Server-Sent Events endpoint
• /sse/message - SSE message endpoint

Authentication Header Format

Include your JustCall API credentials as a Bearer token:

Authorization: Bearer <JWT_TOKEN_BY_OAUTH>
Authorization: Bearer <JUSTCALL_API_KEY>:<JUSTCALL_API_SECRET>

Public Endpoints

The following endpoints are publicly accessible:

• /health - Health check endpoint (returns 200 OK)
• /.well-known/oauth-authorization-server - OAuth2 authorization server metadata

API Usage & Rate Limits

This MCP server uses the JustCall Developer API. All API requests are subject to the rate limits associated with your JustCall API key. Please refer to your JustCall API credentials configuration.

Available Tools

The JustCall MCP Server provides 66 tools organized into the following categories:

JustCall API Tools

📞 Calls (6 tools)

• list_calls - Lists all JustCall calls with various filtering options
• get_call - Get a specific JustCall call by ID
• update_call - Update a JustCall call (disposition, notes, rating)
• get_call_journey - Fetch the sequence of events for a specific call
• get_voice_agent_data - Get voice agent data for a specific call (deprecated, use get_voice_agent_call)
• get_voice_agent_call - Retrieve voice agent related data for a specific call

👥 Users & Agents (3 tools)

• list_users - List all users/agents in the account
• get_user - Get detailed information for a specific user/agent
• update_user_availability - Update a user's availability status to available or unavailable for calls

💬 SMS & Messaging (11 tools)

• send_sms - Send an SMS/text message to a contact
• list_sms - Retrieve all SMS/text messages
• get_sms - Get detailed information for a specific SMS/text message
• check_sms_reply - Check for the most recent inbound SMS reply from a specific contact
• list_sms_tags - Retrieve all SMS tags used for organizing text messages
• get_sms_tag - Get detailed information for a specific SMS tag
• create_sms_tag - Create a new tag for organizing SMS conversations
• delete_sms_tag - Delete a specific SMS tag
• list_sms_threads - Retrieve all SMS threads/conversations associated with a JustCall number
• get_sms_thread - Retrieve a specific SMS thread/conversation by ID
• add_sms_thread_tag - Add tag to an SMS thread/conversation

📇 Contacts (6 tools)

• list_contacts - Retrieve all contacts from the CRM
• get_contact - Retrieve detailed information for a specific contact by ID
• create_contact - Create a new contact in the CRM
• update_contact - Update/modify details of an existing contact
• update_contact_status - Add or remove a contact from DND/DNM/Blacklist lists
• add_contacts_blacklist - Add one or more contacts to the global blacklist in bulk

📊 Analytics (4 tools)

• get_agent_analytics - Retrieve agent analytics data for specified date range
• get_account_analytics - Retrieve account analytics data for specified date range
• get_number_analytics - Retrieve number analytics data for specified date range
• get_sales_dialer_analytics - Retrieve comprehensive analytics data for sales dialer campaigns

🔔 Webhooks (2 tools)

• list_webhooks - Retrieve all configured webhooks
• create_webhook - Create a new webhook endpoint to receive real-time notifications

📱 Phone Numbers (2 tools)

• list_numbers - Retrieve all JustCall phone numbers
• get_number - Retrieve detailed information for a specific JustCall phone number

👥 User Groups (2 tools)

• list_user_groups - Retrieve all user groups defined in the account
• get_user_group - Retrieve detailed information for a specific user group by ID

📅 Appointments (3 tools)

• list_appointment_slots - Retrieve all available time slots for appointments on a specific calendar
• create_appointment - Schedule a new appointment on a specific calendar
• get_appointment - Retrieve details of a specific appointment by its ID

💚 WhatsApp (5 tools)

• list_whatsapp_messages - Retrieve all WhatsApp messages associated with the account
• get_whatsapp_message - Retrieve detailed information for a specific WhatsApp message by ID
• send_whatsapp_message - Send a new WhatsApp message to a contact number
• list_whatsapp_templates - Retrieve all WhatsApp message templates available in the account
• check_whatsapp_message_reply - Check for the most recent inbound WhatsApp message from a contact

🤖 AI Analysis (4 tools)

• list_calls_ai_analysis - Retrieve AI-generated analysis (transcription, summary, insights) for all calls
• get_call_ai_analysis - Retrieve AI-generated analysis for a specific call by Call ID
• list_meetings_ai_analysis - Retrieve AI-generated analysis for recorded meetings (Zoom, Google Meet)
• get_meeting_ai_analysis - Retrieve AI-generated analysis for a specific meeting by Instance ID

🎙️ Voice Agents (2 tools)

• list_voice_agents - Retrieve all AI voice agents associated with the account
• create_voice_agent_call - Initiate an outbound call from a configured AI voice agent to a contact

Sales Dialer Tools

📢 Campaigns (6 tools)

• list_campaigns - Retrieve all sales dialer campaigns
• get_campaign - Retrieve detailed information for a specific sales dialer campaign
• create_campaign - Create a new sales dialer campaign
• update_campaign - Update campaign details including name, description, status, and assignments
• list_salesdialer_campaign_contacts - Retrieve all contacts in a specific campaign
• add_salesdialer_campaign_contact - Add contact to a specific campaign

👥 Contacts (8 tools)