> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gumloop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Use Gumloop as your auth layer

> Call Gmail, Slack, Linear, and custom MCP server tools through Gumloop, with your organization's connector governance applied.

Connect apps to Gumloop once, then use their tools from any MCP client connected to Gumloop. The Gumloop MCP server can call tools on other platforms, including Gmail, Slack, Linear, and custom MCP servers, so you don't have to set up OAuth for every app in every client. Every call still follows your organization's connector governance.

## How it works

Connect [custom MCP servers](/nodes/mcp/custom_mcp_servers) in Gumloop or connect apps from [Connectors settings](https://www.gumloop.com/settings/profile/connectors). The server catalog includes Gumloop-hosted servers, user-deployed Gumstack servers, and custom MCP servers, each with a connection status.

<Steps>
  <Step title="List connected and available servers">
    Call `list_mcp_servers` to browse the servers in the catalog and their connection status.
  </Step>

  <Step title="Inspect a server's tools">
    Call `list_mcp_server_tools` with the `server_id` to see the tools and connection `status`. If it isn't connected, open the returned `gumloop_auth_url` to finish connecting.
  </Step>

  <Step title="Call a tool">
    Call `call_mcp_tool` with `server_id`, `tool_name`, and `arguments`. Include the optional `ref` to have it echoed in the results.
  </Step>
</Steps>

Use `list_teams` to find team IDs. For team-owned connections, pass the team ID as `project_id`.

Other MCP capabilities include:

* List resources with `list_mcp_resources` and read them with `read_mcp_resource`.
* List prompts with `list_mcp_prompts` and render them with `get_mcp_prompt`.

For example, call `call_mcp_tool` with these arguments to list five recent emails through a Gmail connection:

```json theme={"dark"}
{
  "server_id": "gmail",
  "tool_name": "list_emails",
  "arguments": {
    "max_results": 5
  }
}
```

## Example prompts

<Prompt description={`Using my Gmail connection in Gumloop, find unread emails from today.`} icon="envelope" actions={["copy"]}>
  Using my Gmail connection in Gumloop, find unread emails from today.
</Prompt>

<Prompt description={`Create a Linear issue through Gumloop for the bug we discussed, and assign it to me.`} icon="list-check" actions={["copy"]}>
  Create a Linear issue through Gumloop for the bug we discussed, and assign it to me.
</Prompt>

<Prompt description={`Search my Slack messages through Gumloop for the latest project update.`} icon="slack" actions={["copy"]}>
  Search my Slack messages through Gumloop for the latest project update.
</Prompt>

<Prompt description={`Use my connected Notion tools through Gumloop to find the launch checklist.`} icon="book" actions={["copy"]}>
  Use my connected Notion tools through Gumloop to find the launch checklist.
</Prompt>

## Governance

Tool calls made through the Gumloop MCP server follow the same connector governance as tool calls made by Gumloop agents.

* **Credentials stay in Gumloop.** Tools run inside Gumloop. Your MCP client receives tool results, never the app's OAuth tokens.
* **Custom roles.** If a [custom role](/enterprise-features/user_groups) blocks an app or a specific tool, `list_mcp_servers` shows that server as blocked and `call_mcp_tool` rejects the call.
* **App Rules.** Organization [App Rules](/enterprise-features/app-policies/app-rules) are checked on each call and can block it based on the tool and its arguments.
* **Account restrictions.** [Domain restrictions](/enterprise-features/app-policies/domain-restrictions) and [App Claims](/enterprise-features/app-policies/app-claims) control which accounts and workspaces people can connect.
* **Activity.** Calls appear in [Connector Activity](/enterprise-features/app_activity), so admins can see who called which tool, from which source, and whether it succeeded.

You can call the same MCP tools through the [REST API](/api-reference/mcp/call-tool) or the [Gumloop CLI](/cli/mcp).