@@ -82,9 +82,15 @@ describe("run", () => {
     expect(exit).toHaveBeenCalledWith(1);
   });
 
-  it("does not start anything when imported", () => {
-    // The module was imported above, under vitest rather than as the binary.
+  it("does not start anything when imported", async () => {
+    // A fresh import, under vitest rather than as the binary: the entry-point
+    // guard must keep it from starting any transport.
+    vi.resetModules();
+    await import("../index.js");
     expect(startStdioServer).not.toHaveBeenCalled();
+    expect(startSseServer).not.toHaveBeenCalled();
+    expect(startStreamableHttpServer).not.toHaveBeenCalled();
+    expect(exit).not.toHaveBeenCalled();
   });
 });
 
 
@@ -163,9 +163,16 @@ describe("toggle-simulated-logging", () => {
     const leaving = await connect();
     await toggle(leaving);
     await vi.waitFor(() => expect(messages(leaving)).toHaveLength(1));
+    // A closed client receives nothing either way, so check the server side:
+    // an interval that outlived cleanup would log each failed send.
+    const errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
     await leaving.close();
     await vi.advanceTimersByTimeAsync(20000);
     expect(messages(leaving)).toHaveLength(1);
+    expect(errorSpy).not.toHaveBeenCalledWith(
+      "Simulated logging message failed:",
+      expect.anything(),
+    );
   });
 
   it("logs, rather than throws, a message that cannot be sent", async () => {
 
@@ -231,14 +231,27 @@ describe("resource subscriptions", () => {
     await session.client.subscribeResource({ uri: URI });
     await leaving.close();
 
-    await session.client.callTool({
-      name: "toggle-subscriber-updates",
-      arguments: {},
-    });
-    await vi.waitFor(() => expect(updates()).toEqual([URI]));
-    expect(
-      ofMethod(leaving.notifications, "notifications/resources/updated"),
-    ).toEqual([]);
+    // A new client under the departed session's id, which never subscribed:
+    // if cleanup had left the old subscription behind, its updates would
+    // reach this client.
+    const returning = await connect({ sessionId: leaving.sessionId });
+    try {
+      await returning.client.callTool({
+        name: "toggle-subscriber-updates",
+        arguments: {},
+      });
+      await session.client.callTool({
+        name: "toggle-subscriber-updates",
+        arguments: {},
+      });
+      await vi.advanceTimersByTimeAsync(5000);
+      expect(updates()).toEqual([URI, URI]);
+      expect(
+        ofMethod(returning.notifications, "notifications/resources/updated"),
+      ).toEqual([]);
+    } finally {
+      await returning.close();
+    }
   });
 
   it("logs, rather than throws, an update that cannot be sent", async () => {