Claude Desktop quickstart

1. Get an OpenPhn API key

See the Quickstart. You need an sk_live_* key on a verified account.

2. Edit your Claude Desktop config

Claude Desktop reads MCP config from:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

Add an mcpServers entry for the hosted SSE endpoint:

{
  "mcpServers": {
    "openphn": {
      "type": "sse",
      "url": "https://mcp.openphn.com",
      "headers": {
        "Authorization": "Bearer sk_live_..."
      }
    }
  }
}

The key lives in the config file on your machine. Treat it like any other secret — don't commit this file to a shared repo.

3. Restart Claude Desktop

Fully quit (not just close the window) and reopen. Within a few seconds the OpenPhn tools appear in the attachment menu:

make_call
get_call
list_calls
list_numbers

4. Place a call from a Claude chat

Use openphn to call +14155551234 and confirm that order #A-14421 is going to ship today. Return { will_ship_today: bool, tracking?: string, eta?: datetime }.

Claude invokes make_call; OpenPhn dials the number and streams status. When the call completes, Claude reads the outcome back with get_call and formats the result.

Troubleshooting

Tools don't appear — make sure you fully quit and reopened Claude Desktop. SSE connections are only established on app launch.
401 errors — your Authorization header is missing or the key is revoked. Check /auth/me on REST first.
403 errors — your account is still pending_review, or the key lacks calls:create / calls:read scope.
Corporate proxy blocks SSE — use the local stdio transport instead; see the Tool reference.