Client Transports

Clients can use any MCP transport. The transport is passed to client_runtime::create_client() (via McpClientOptions) or, for Streamable HTTP, to client_runtime::with_transport_options():

// Stdio - launch a server subprocess
let transport = StdioTransport::create_with_server_launch("my-server", vec![], None, TransportOptions::default())?;

// Streamable HTTP - connect to a remote server
let transport_options = StreamableTransportOptions {
    mcp_url: "https://mcp.example.com/mcp".into(),
    request_options: RequestOptions {
        ..Default::default()
    },
};

let client = client_runtime::with_transport_options(
    client_details,
    transport_options,
    handler,
    None,
    None,
    None,
);

// SSE - connect to a legacy server
let transport = ClientSseTransport::new(
    "https://mcp.example.com/sse",
    ClientSseTransportOptions {
        ..Default::default()
    },
)?;

StreamableTransportOptions.request_options and ClientSseTransportOptions also support request timeouts, retry behavior, and custom HTTP headers for auth tokens.