Method handle

mcp/server.go:1424–1453

handle invokes the method described by the given JSON RPC request.

(ctx context.Context, req *jsonrpc.Request)

// handle invokes the method described by the given JSON RPC request.
func (ss *ServerSession) handle(ctx context.Context, req *jsonrpc.Request) (any, error) {
	ss.mu.Lock()
	initialized := ss.state.InitializeParams != nil
	ss.mu.Unlock()

	// From the spec:
	// "The client SHOULD NOT send requests other than pings before the server
	// has responded to the initialize request."
	switch req.Method {
	case methodInitialize, methodPing, notificationInitialized:
	default:
		if !initialized {
			ss.server.opts.Logger.Error("method invalid during initialization", "method", req.Method)
			return nil, fmt.Errorf("method %q is invalid during session initialization", req.Method)
		}
	}

	// modelcontextprotocol/go-sdk#26: handle calls asynchronously, and
	// notifications synchronously, except for 'initialize' which shouldn't be
	// asynchronous to other
	if req.IsCall() && req.Method != methodInitialize {
		jsonrpc2.Async(ctx)
	}

	// For the streamable transport, we need the request ID to correlate
	// server->client calls and notifications to the incoming request from which
	// they originated. See [idContextKey] for details.
	ctx = context.WithValue(ctx, idContextKey{}, req.ID)
	return handleReceive(ctx, ss, req)
}

// InitializeParams returns the InitializeParams provided during the client's
// initial connection.