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The MCP Servers integration lets you connect external Model Context Protocol (MCP) servers to Modem. Once connected, the Modem Agent can discover and use tools from those servers alongside its built-in capabilities.
MCP Servers is currently in beta. Functionality may change.

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Prerequisites

  • Admin or Owner access to your Modem organization
  • An MCP-compatible server with a publicly accessible HTTPS endpoint

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Setup

1

Open MCP Servers settings

Go to Settings → MCP Servers in your Modem dashboard.
2

Add a server

Click Add Server. Enter a name, slug (used for tool namespacing), and the server URL.
The URL must use HTTPS. Localhost, private IP addresses, and .local domains are not allowed.
3

Choose a transport type

Select the transport protocol your server uses:
  • HTTP (Streamable) — The default for most MCP servers.
  • SSE (Legacy) — For older servers that use Server-Sent Events.
4

Configure authentication

Choose the authentication method your server requires. See Authentication below.
5

Test the connection

Click Test Connection to verify Modem can reach your server and discover its tools. If the test passes, you’ll see a list of available tools.
6

Save

Click Save. The server’s tools are now available to the Modem Agent.

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Authentication

MCP servers support three authentication methods:

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None

No authentication. Use this for servers that handle auth at the network level or don’t require it.

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Bearer Token

Modem sends an Authorization: Bearer <token> header with every request. Enter your token during setup — it’s encrypted at rest and never exposed in API responses.

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Custom Headers

Define one or more custom HTTP headers that Modem sends with every request. Use this for API key headers, custom auth schemes, or any other header-based authentication your server expects.

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How Tools Appear to the Agent

When you connect an MCP server, the agent discovers its tools automatically at the start of each conversation.
  • Namespacing. Tools are prefixed with the server’s slug to avoid name collisions. For example, a tool called search on a server with slug my-server becomes ext_my_server_search.
  • Approval required. All external tools require user confirmation before the agent executes them. The agent will describe what it wants to do and wait for you to approve.
  • Tool descriptions. Descriptions from your server are passed through to the agent (truncated to 500 characters).

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Enabling and Disabling Servers

You can disable an entire server without deleting it by toggling it off. Disabled servers are skipped during tool discovery.

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Permissions

ActionRequired Role
View servers and toolsAny member
Add, edit, or remove serversAdmin or Owner
Test connectionsAdmin or Owner

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Troubleshooting

  • Verify your server URL is correct and uses HTTPS
  • Check that the server is publicly accessible (not behind a VPN or firewall)
  • Confirm your authentication credentials are correct
  • Make sure the server responds within 15 seconds
  • Run Test Connection to verify tool discovery works
  • Check that the server is enabled
  • Verify the server hasn’t been disabled
The agent connects to all enabled MCP servers at the start of each conversation. If a server is slow to respond, it can delay tool discovery.
  • Check your server’s response time
  • Disable servers you’re not actively using
  • The connection timeout is 10 seconds — servers that don’t respond in time are skipped
  • Check your server logs for errors
  • Verify the server is still running and accessible
  • Confirm authentication credentials haven’t expired or been rotated
  • Try running Test Connection again to see if the server is reachable

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Removing a Server

To remove an MCP server:
  1. Go to Settings → MCP Servers
  2. Click on the server you want to remove
  3. Click Delete
If you want to temporarily stop the agent from using a server without deleting it, disable the server instead. Disabled servers keep their configuration but are skipped during tool discovery.