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

# MCP Connections

> Connect external MCP servers so your AI agents can use their read-only tools.

## Overview

MCP Connections let your AI agents call tools from vetted external services (such as Stripe, GitHub, Notion, Slack, and Google Workspace), using the Model Context Protocol (MCP). Connections are **read-only** and managed per workspace under **Settings → AI → MCP Connections**.

## How it works

* The catalog lists vetted servers. Each connects with either an **API key** (token) or **OAuth**.
* Connecting a server discovers its read-only tools and makes them available to your agents automatically.
* Tools are namespaced as `mcp__<server>__<tool>` and never expose write or destructive actions.
* OAuth servers (Notion, Slack, Google) use a consent redirect; token servers (Stripe, GitHub) take a read-only API key.

## Using it

1. Go to **Settings → AI → MCP Connections**.
2. Pick a server and choose **Connect**.
   * **API-key servers**: paste a read-only key.
   * **OAuth servers**: approve access on the provider's consent screen.
3. Toggle a connection **Enabled / Disabled** to control whether agents may use it.
4. **Disconnect** removes the connection and its stored credential.

Once connected and enabled, the server's read-only tools are available to your chat agents on their next message. No further setup required.

## Troubleshooting

* **The agent says a server is "not connected."** The server isn't connected, or the connection is disabled. Connect or enable it under Settings → AI → MCP Connections.
* **A connection shows an "Errored" badge.** The API key was revoked, or an OAuth token could not be refreshed. Disconnect and reconnect the server.
* **No tools appear after connecting.** The server may not advertise read-only tools, or the API key lacks read scope. Use a read-scoped key.
* **The OAuth redirect fails or returns to the consent screen.** Confirm the server's endpoint is reachable and that a workspace admin approved the consent.
* **A tool the agent expected is missing.** Only read-only tools are exposed; write and destructive tools are intentionally hidden.

## Related

* [AI Settings](/ai/overview)
* [Chat Agents](/ai/chat-agents/overview)


## Related topics

- [AI](/ai/overview.md)
- [Provider Tools](/ai/provider-tools.md)
- [MCP Server](/dev/mcp/overview.md)
- [List MCP tools](/api-reference/mcp/list-mcp-tools.md)
- [CLI](/dev/cli/overview.md)