Fonoster MCP Server

MCP Server for the Fonoster API, enabling MCP clients to interact with Fonoster's telephony services. This module is part of the Fonoster open-source project. For more information about the project, please visit https://github.com/fonoster/fonoster.

Tools

1. list_numbers

   • Returns a list of numbers from Fonoster in a table format (using markdown)

   • Optional inputs:

     • page_size (number): Maximum number of numbers to return

     • page_token (string): Pagination token for next page

   • Returns: List of numbers with their refs, names, and telUrls

2. list_applications

   • Lists applications from Fonoster in a table format (using markdown)

   • Optional inputs:

     • page_size (number): Maximum number of applications to return

     • page_token (string): Pagination token for next page

   • Returns: List of applications with their refs, names, endpoints, creation dates, update dates, and types

3. create_call

   • Creates a call from Fonoster

   • Required inputs:

     • from (string): The number to call from

     • to (string): The number to call to

     • app_ref (string): The reference to the application to use for the call

     • metadata (object): Metadata to be sent to the application

   • Returns: Call creation confirmation with reference ID

4. create_call_batch

   • Creates a batch of calls from Fonoster

   • Required inputs:

     • from (string): The number to call from

     • to_array (array): The numbers to call to

     • app_ref (string): The reference to the application to use for the call

     • metadata (object): Metadata to be sent to the application

   • Returns: Batch creation confirmation with reference ID

Related MCP server: twilio-mcp

Prompts

1. create_call_prompt

   • A prompt for creating a call step by step

   • Guides an MCP client through the process of:

     • Asking the user for the number or numbers to call if not already provided

     • Offering a list of available numbers using the list_numbers tool

     • Asking for the application name and finding its reference

     • Creating a call using the create_call or create_call_batch tool depending on the user's request

Setup

Usage with Claude Desktop

Add the following to your claude_desktop_config.json:

If you are logged in to the command-line tool, simply run fonoster mcp:configure --client claude to configure the server.

npx

{
  "mcpServers": {
    "fonoster": {
      "command": "npx",
      "args": [
        "-y",
        "@fonoster/mcp"
      ],
      "env": {
        "MCP_WORKSPACE_ACCESS_KEY_ID": "your-workspace-access-key-id",
        "MCP_APIKEY_ACCESS_KEY_ID": "your-apikey-access-key-id",
        "MCP_APIKEY_ACCESS_KEY_SECRET": "your-apikey-access-key-secret"
      }
    }
  }
}

docker

{
  "mcpServers": {
    "fonoster": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "MCP_WORKSPACE_ACCESS_KEY_ID",
        "-e",
        "MCP_APIKEY_ACCESS_KEY_ID",
        "-e",
        "MCP_APIKEY_ACCESS_KEY_SECRET",
        "fonoster/mcp"
      ],
      "env": {
        "MCP_WORKSPACE_ACCESS_KEY_ID": "your-workspace-access-key-id",
        "MCP_APIKEY_ACCESS_KEY_ID": "your-apikey-access-key-id",
        "MCP_APIKEY_ACCESS_KEY_SECRET": "your-apikey-access-key-secret"
      }
    }
  }
}

Environment Variables

Testing with the MCP Inspector

MCP_WORKSPACE_ACCESS_KEY_ID="your-workspace-access-key-id" \
MCP_APIKEY_ACCESS_KEY_ID="your-apikey-access-key-id" \
MCP_APIKEY_ACCESS_KEY_SECRET="your-apikey-access-key-secret" \
npx @modelcontextprotocol/inspector \
node /path/to/fonoster/mods/mcp/dist/index.js

Troubleshooting

If you encounter authentication errors, verify that:

1. Your Fonoster credentials are correct

2. The environment variables are properly set

3. You have the necessary permissions to access the Fonoster API

Build

Docker build:

docker build -t fonoster/mcp -f Dockerfile .