MCP Servers

MCP servers provide tools that your agents can use to interact with external APIs and services. Once created, these servers are automatically synced to discover available tools, which can then be added to your agent graphs.

Creating an MCP server

1. Go to the MCP Servers tab in the left sidebar, then select "New MCP server".

2. Fill in the required server details:

3. Optionally, configure additional settings:

4. Click "Create" to create the server.

Viewing server details

After creating an MCP server, you can view its details:

1. Click on your created MCP server from the list
2. The server details page shows:
   • Server information - URL, transport type, creation date, etc.
   • Status - healthy, unhealthy, unknown, disabled, or shows a "Click to Login" button if OAuth 2.1/PKCE flow is detected
   • Active tools - Currently enabled tools for the server
   • Available tools - All tools discovered from the server with descriptions and parameters

Editing server settings

To modify an existing MCP server:

1. From the server details page, click the Edit button
2. The edit form shows all the same fields as creation, plus the ability to update Active Tools. By default, all available tools are enabled. You can select specific tools to enable.
3. Click Save to apply changes

Authentication setup

If your MCP server requires authentication, you have two options: either use the "Click to Login" button to authenticate or manually create a credential to use with the MCP server.

OAuth 2.1/PKCE authentication

1. Create your MCP server without selecting a credential
2. Go to the server details page and click the "Click to Login" button
3. Complete the OAuth authentication flow in your browser
4. The credential will be automatically created and saved to your keychain

Popular MCP servers with OAuth 2.1/PKCE support

Manual credential setup

1. Create a credential in the Credentials section. The credential can be API Key, Bearer Token, Basic, OAuth 2.0, etc.
2. When creating or editing your MCP server, select the credential from the dropdown
3. The credential will be automatically used when connecting to the server

Finding more remote MCP servers

For additional remote MCP servers you can connect to:

• Anthropic's Remote MCP Servers - Official documentation with curated third-party remote servers
• Awesome Remote MCP Servers - Community-curated list of high-quality remote MCP servers

Using stdio-based MCP servers

The Visual Builder requires Streamable HTTP or SSE transport to connect to MCP servers. If you have an MCP server that runs in stdio mode locally, you can use the following setup to connect to it.

Setup outline

1. Deploy your stdio -> Streamable HTTP/SSE bridge (locally or cloud)
2. Set environment variables (API tokens, etc.)
3. Verify it's running (i.e. on port 4000, 4001, etc.)
4. Add to Visual Builder:
   • URL: http://localhost:4000/mcp (or your server URL)
   • Transport Type: Streamable HTTP or SSE

Example using mcp-proxy

1. Get familiar with mcp-proxy - proxy for MCP servers that use stdio transport
2. Supabase MCP server
3. Run the server locally:

SUPABASE_ACCESS_TOKEN=YOUR_SUPABASE_ACCESS_TOKEN mcp-proxy --port 4444 --shell "npx -y @supabase/mcp-server-supabase@latest --read-only"

4. Add to Visual Builder with the following settings:
   • URL: http://localhost:4444/mcp
   • Transport Type: Streamable HTTP

Adding servers to graphs

Once you have created an MCP server, you can add it to your graphs:

1. Go to the Graphs page
2. Drag and drop an MCP server into your graph
3. Connect the MCP server to an agent by dragging from the server's connector to the agent
4. Your agent can now use the tools provided by that MCP server

For detailed instructions on working with MCP servers in graphs, see the Graphs page.