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

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
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
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
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

Prompts

create_call_prompt
- A prompt for creating a call step by step
- Guides Claude 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:

npx

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

docker

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

Testing with the MCP Inspector

WORKSPACE_ACCESS_KEY_ID="your-workspace-access-key-id" \
APIKEY_ACCESS_KEY_ID="your-apikey-access-key-id" \
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:

Your Fonoster credentials are correct
The environment variables are properly set
You have the necessary permissions to access the Fonoster API

Build

Docker build:

docker build -t fonoster/mcp -f Dockerfile .