MCP server user authentication

yielding-jade · 2025-06-07T21:56:04.660Z

How do I add a user token to MCP server tool call when voice agent makes a call to my own mcp server?

V

To add a user token to your MCP server tool call, you can configure the tool/server with custom headers, such as:

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer your-user-token"
    }
  }
}

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer your-user-token"
    }
  }
}

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer your-user-token"
    }
  }
}

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer your-user-token"
    }
  }
}

This will include the user token in each request from the voice agent to your MCP server. For more details, see the server authentication documentation.

Quick question:
Do you need to set a different user token for each call (per user/session), or is a static token sufficient for your use case?

Sources:

⤵️ Mention @Vapi Support Bot for follow-ups 🐥

Y

yielding-jadeOP•6/7/25, 10:03 PM

@Duckie different user token for each call per user session

V

Vapi Support BotAPP•6/7/25, 10:04 PM

To set a different user token for each call/session, configure the
Authorization
Authorization
Authorization
Authorization header at the tool call level in your MCP tool configuration. This allows you to pass a unique token per request:

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer <user-session-token>"
    }
  }
}

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer <user-session-token>"
    }
  }
}

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer <user-session-token>"
    }
  }
}

{
  "server": {
    "url": "https://your-mcp-server.com/endpoint",
    "headers": {
      "Authorization": "Bearer <user-session-token>"
    }
  }
}

For more details, see the server authentication documentation.

Clarifying question:
Are you looking to set the user token dynamically via API/backend code, or do you need to configure this manually in the dashboard for each call?

Sources:

K

KyleAPP•6/10/25, 2:36 AM

checking if this is resolved/solved for you?

Y

yielding-jadeOP•6/11/25, 11:47 AM

nope can't pass in unique token per session on header with liquidJS

K

KyleAPP•6/12/25, 6:49 AM

I see that you have two tickets open with the same request. I will close this one and respond to you on the other ticket.

Y

yielding-jadeOP•6/12/25, 10:01 AM

sure

G

generous-coffee•10/6/25, 1:55 PM

any update on this issue?

K

KyleAPP•11/18/25, 4:32 AM

I sincerely apologize for the delayed response to your support request.
We implemented better tracking for support tickets to ensure timely responses going forward, but due to a technical limitation, this only applies to tickets created after this past week.
I'm closing this older ticket, but if your issue still needs attention, please:
Reply with 'REOPEN' or
Email support@vapi.ai with any updates
I'll personally ensure your new request gets prompt attention.
Thank you for your patience.
Best regards,
Vapi Support Team

MCP server user authentication

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