Stdio

1. Create a configuration with an empty mcp section, and start agentgateway. You add the MCP server in the UI.

   cat <<'EOF' > config.yaml
   # yaml-language-server: $schema=https://agentgateway.dev/schema/config
   mcp:
     port: 3000
     targets: []
   EOF
   agentgateway -f config.yaml

2. Open http://localhost:15000/ui/mcp/servers (MCP > Servers), and click Add server.

3. Enter everything for the Server name, and select the Command Line transport.

4. Enter npx for the Command and @modelcontextprotocol/server-everything for the Arguments.

   

   

5. Click Save server.

The UI writes the same everything target as the example configuration, plus an empty env map and clear_env: false. The UI splits Arguments on spaces. For an argument that contains a space, use the Raw icon (<>) in the drawer header.

The example configuration also sets a CORS policy for the UI playground. In the UI, you add that policy with Apply CORS when you verify the setup in the next section.

Whether the UI can save depends on your storage mode. For more information, see Save changes from the UI.

1. Download an MCP configuration for your agentgateway.

   curl -L https://agentgateway.dev/examples/mcp-basic/config.yaml -o config.yaml

2. Review the configuration file.

   cat config.yaml
   config.yaml

   mcp:
     port: 3000
     policies:
       cors:
         allowOrigins:
         - "*"
         allowHeaders:
         - mcp-protocol-version
         - content-type
         - cache-control
         - mcp-session-id
         exposeHeaders:
         - "Mcp-Session-Id"
     targets:
     - name: everything
       stdio:
         cmd: npx
         args: ["@modelcontextprotocol/server-everything"]

   Review the following table to understand this configuration.

   Field	Description
   mcp	The top-level MCP configuration block that defines how agentgateway connects to MCP servers.
   port	The port on which agentgateway listens for incoming MCP requests, such as 3000. If not specified, a default port is used.
   targets	A list of MCP targets to connect to. Each target defines an MCP server that agentgateway proxies requests to. At least one target is required.
   name	A unique name for the MCP target, such as server-everything. This name identifies the target in logs and the UI.
   stdio	Configuration for connecting to an MCP server via standard input/output. Use this for local MCP servers that run as a command. Contains cmd (the command to run) and args (arguments for the command). In this example, npx runs the @modelcontextprotocol/server-everything package.
   mcp	Configuration for connecting to a remote MCP server via streamable HTTP. Use this for remote MCP servers. Contains host (the URL of the MCP server endpoint).

3. Run the agentgateway.

   agentgateway -f config.yaml