fix(server): clean sigint handler on shutdown

src/__tests__/server.test.ts

@@ -26,6 +26,7 @@ describe('runServer', () => {
   let mockHttpHandle: HttpServerHandle;
   let mockClose: jest.Mock;
   let processOnSpy: jest.SpyInstance;
+  let processOffSpy: jest.SpyInstance;
 
   beforeEach(() => {
     jest.clearAllMocks();
@@ -51,15 +52,17 @@ describe('runServer', () => {
 
     MockStartHttpTransport.mockResolvedValue(mockHttpHandle);
 
-    // Spy on process.on method
+    // Spy on process methods
     processOnSpy = jest.spyOn(process, 'on').mockImplementation();
+    processOffSpy = jest.spyOn(process, 'off');
 
     // Mock process.exit to prevent Jest from exiting
     jest.spyOn(process, 'exit').mockImplementation((() => {}) as never);
   });
 
   afterEach(() => {
     processOnSpy.mockRestore();
+    processOffSpy.mockRestore();
     // Note: We don't call jest.restoreAllMocks() here as it would clear module mocks
     // The memoization cache persists across tests, which is expected behavior
   });
@@ -175,6 +178,7 @@ describe('runServer', () => {
 
     await serverInstance.stop();
 
+    expect(processOffSpy).toHaveBeenCalledWith('SIGINT', expect.any(Function));
     expect(serverInstance.isRunning()).toBe(false);
     expect({
       events: MockLog.info.mock.calls

src/server.ts

@@ -129,6 +129,7 @@ const runServer = async (options: ServerOptions = getOptions(), {
   let transport: StdioServerTransport | null = null;
   let httpHandle: HttpServerHandle | null = null;
   let unsubscribeServerLogger: (() => void) | null = null;
+  let sigintHandler: (() => void) | null = null;
   let running = false;
   let onLogSetup: ServerOnLog = () => () => {};
 
@@ -144,6 +145,11 @@ const runServer = async (options: ServerOptions = getOptions(), {
         httpHandle = null;
       }
 
+      if (sigintHandler) {
+        process.off('SIGINT', sigintHandler);
+        sigintHandler = null;
+      }
+
       log.debug('...closing Server');
       await server?.close();
       running = false;
@@ -246,10 +252,11 @@ const runServer = async (options: ServerOptions = getOptions(), {
           })));
     });
 
-    if (enableSigint) {
-      process.on('SIGINT', () => {
+    if (enableSigint && !sigintHandler) {
+      sigintHandler = () => {
         void stopServer();
-      });
+      };
+      process.on('SIGINT', sigintHandler);
     }
 
     if (options.isHttp) {