Skip to main content

stdio Transport

Connect agentgateway to local process-based MCP servers

The stdio transport connects agentgateway to MCP servers that run as local processes, communicating via standard input/output.

Overview​

stdio transport is ideal when:

  • MCP servers run as local command-line tools
  • You want to manage MCP server lifecycle with agentgateway
  • The server is distributed as an npm package or binary

Quick start​

# Download the stdio MCP configuration
curl -L https://agentgateway.dev/examples/mcp-basic/config.yaml -o config.yaml

# Run agentgateway
agentgateway -f config.yaml

Configuration​

Configure an stdio MCP backend in your config.yaml:

# yaml-language-server: $schema=https://agentgateway.dev/schema/config
mcp:
  port: 3000
  targets:
  - name: my-mcp-server
    stdio:
      cmd: npx
      args:
        - "-y"
        - "@modelcontextprotocol/server-everything"

Example: MCP test server​

The MCP test server (@modelcontextprotocol/server-everything) is useful for testing:

mcp:
  port: 3000
  targets:
  - name: test-server
    stdio:
      cmd: npx
      args:
        - "-y"
        - "@modelcontextprotocol/server-everything"

Example: Filesystem MCP server​

Expose local filesystem access via MCP:

mcp:
  port: 3000
  targets:
  - name: filesystem
    stdio:
      cmd: npx
      args:
        - "-y"
        - "@modelcontextprotocol/server-filesystem"
        - "/path/to/allowed/directory"

Why use agentgateway?​

Direct stdioWith agentgateway
One client per serverMultiple clients share servers
No authenticationOAuth2, API keys, or custom auth
No access controlTool-level authorization
Client manages processGateway manages lifecycle
No metricsFull observability with OpenTelemetry

Verify access​

  1. Open the agentgateway UI to view your configuration
  2. Go to Playground to test tools
  3. Click Connect to retrieve available tools
  4. Select a tool and click Run Tool to test

Learn more​