A Service I Use Published an MCP Server but I Don’t See It in Gumloop — How Do I Connect It?

Last updated: May 14, 2026

Gumloop supports connecting to any third-party MCP server — even ones that aren’t listed as a built-in integration. If a service like Meta, Stripe, or Cloudflare has published their own MCP server URL, you can add it directly to your agent using the Add MCP Server option.

Why Don’t I See It as a Built-In App?

Gumloop ships with 50+ pre-built integrations (Google Sheets, Slack, HubSpot, etc.), but hundreds of other companies also publish their own MCP servers independently. These won’t appear in the default app list because they’re hosted by the third party, not by Gumloop. Gumloop’s custom MCP server feature lets you connect to any of them in under a minute.

How to Connect a Third-Party MCP Server to Your Agent

  1. Open your agent and click +App (or Add tools) in the tools panel.

  2. Switch to the Custom tab at the top of the panel.

  3. Click Add MCP Server.

  4. Paste the MCP server URL provided by the third-party service (for example, Meta’s Ads MCP URL is https://mcp.facebook.com/ads).

  5. Give it a Label (e.g., “Meta Ads”) so you can identify it later.

  6. If the service requires authentication, fill in the Access Token / API Key field or the Additional Header field. Some servers support automatic OAuth discovery — Gumloop will walk you through the flow if detected.

  7. Click Connect.

Your agent now has access to every tool the MCP server exposes. Ask your agent to “list available tools” to verify the connection is working.

Where Do I Find the MCP URL for a Service?

The MCP server URL is published by the service itself — not by Gumloop. Look for it in:

  • The service’s developer documentation (search for “MCP server” or “Model Context Protocol”)

  • Their API or integrations page

  • Announcements on their blog or changelog

Some well-known examples:

  • Meta Ads: https://mcp.facebook.com/ads

If you can’t find a published MCP URL, the service may not offer one yet. In that case, see the docs on building or hosting your own custom MCP server.

Requirements for Custom MCP Servers

  • The URL must use HTTPS — HTTP connections are rejected.

  • The server must be publicly accessible on the internet (no localhost or private network URLs).

  • The server must support Streamable HTTP or Server-Sent Events (SSE) transport.

Troubleshooting

  • Can’t connect: Verify the URL starts with https:// and the server is publicly reachable. Some servers require you to enable API access in their dashboard first.

  • Authentication failed: Double-check that your API key or token is valid and hasn’t expired. If the server uses OAuth, make sure you complete the authorization flow when prompted.

  • Tools not appearing: Ask your agent to “list available tools from [server name]” to force a refresh. If tools still don’t appear, the server may not implement MCP tool discovery correctly.

  • Anthropic models and custom headers: Anthropic models (Claude) do not forward custom headers set in the Additional Header field. If your MCP server requires a custom header for authentication, use the Access Token / API Key field with a bearer token instead, or use an OpenAI or Gemini model.

Alternative: Add the Credential First, Then Attach to Agent

You can also set up the MCP server credential separately and attach it later:

  1. Go to Settings → Credentials and search for “MCP Server.”

  2. Click Add credential and fill in the URL, label, and authentication details.

  3. The credential is now available to attach to any agent via +App → Custom tab.

Still Need Help?

If this didn’t resolve your issue, reach out to support at support@gumloop.com.

Related Docs