diff --git a/server/sse.go b/server/sse.go
index 9a4191500..64618399c 100644
--- a/server/sse.go
+++ b/server/sse.go
@@ -51,6 +51,12 @@ func (s *sseSession) Initialized() bool {
 
 var _ ClientSession = (*sseSession)(nil)
 
+// Server is a type that implements ListenAndServe and Shutdown
+type Server interface {
+	ListenAndServe() error
+	Shutdown(ctx context.Context) error
+}
+
 // SSEServer implements a Server-Sent Events (SSE) based MCP server.
 // It provides real-time communication capabilities over HTTP using the SSE protocol.
 type SSEServer struct {
@@ -61,7 +67,7 @@ type SSEServer struct {
 	messageEndpoint              string
 	sseEndpoint                  string
 	sessions                     sync.Map
-	srv                          *http.Server
+	srv                          Server
 	contextFunc                  SSEContextFunc
 
 	keepAlive         bool
@@ -131,7 +137,7 @@ func WithSSEEndpoint(endpoint string) SSEOption {
 }
 
 // WithHTTPServer sets the HTTP server instance
-func WithHTTPServer(srv *http.Server) SSEOption {
+func WithHTTPServer(srv Server) SSEOption {
 	return func(s *SSEServer) {
 		s.srv = srv
 	}
@@ -165,6 +171,7 @@ func NewSSEServer(server *MCPServer, opts ...SSEOption) *SSEServer {
 		sseEndpoint:                  "/sse",
 		messageEndpoint:              "/message",
 		useFullURLForMessageEndpoint: true,
+		srv:                          nil, // will be set by Start
 		keepAlive:                    false,
 		keepAliveInterval:            10 * time.Second,
 	}
@@ -190,9 +197,11 @@ func NewTestServer(server *MCPServer, opts ...SSEOption) *httptest.Server {
 // It sets up HTTP handlers for SSE and message endpoints.
 func (s *SSEServer) Start(addr string) error {
 	s.mu.Lock()
-	s.srv = &http.Server{
-		Addr:    addr,
-		Handler: s,
+	if s.srv == nil {
+		s.srv = &http.Server{
+			Addr:    addr,
+			Handler: s,
+		}
 	}
 	s.mu.Unlock()