Connect to n8n MCP

Overview

There are two ways how n8n workflows can be triggered via MCP in n8n:

1. Instance-level MCP - recommended
2. MCP Server Trigger node (more details)

In the following we focus on the more flexible instance-level MCP access. The differences are described in the official n8n documentation:

Instance-level MCP access lets you create one connection per n8n instance, use centralized authentication, and choose which workflows to enable for access. Enabled workflows are easy to find and run without extra setup for each workflow.

In comparison, you configure an MCP Server Trigger node inside a single workflow. This node exposes tools only from that workflow, a useful approach when you want to craft a specific MCP server behavior within one workflow.

Setup

1. Get MCP URL

• In the n8n Settings, enable the instance level MCP Server for your n8n server. Then click on "Connection details".

• The official n8n documentation provides detailed instructions.

2. Example Workflow

• Below is an example workflow. With a very basic setup: A chat trigger node and an HTTP request node.
• To try HTTP requests you can use webhook.site for example, which is a free tool to register calls to a webhook.

3. Enable Workflow MCP access

• In n8n "Settings > Instance-level MCP" click "Enable workflow

• Select a workflow that fulfills the aforementioned conditions (published and one of the four required trigger types).
• Click "Enable"

• Your workflow should be listed in this view:

4. Create Assistant

• In your meinGPT workspace, create an assistant and click on "Add Tool".

5. Add Tool

• Click on "Add Tool" and select "Custom MCP".

• Paste the URL of your n8n instance in the "URL" field.

6. Connect Tool

• Save your assistant and start a chat with it

• You'll be prompted to setup the OAuth connection with your n8n MCP server.

• Click on "Connect" and do the OAuth flow

7. Verify Connection

• When the connection was successfully established, you'll be presented this screen:

8. Use the MCP Server

• Now you can start using your workflows via an assistant. Prompts you can try:
  • "What workflows do you see?"
  • "Run workflow xyz"