diff --git a/src/everything/__tests__/resources.test.ts b/src/everything/__tests__/resources.test.ts
index a22b904175..c70f991340 100644
--- a/src/everything/__tests__/resources.test.ts
+++ b/src/everything/__tests__/resources.test.ts
@@ -22,6 +22,7 @@ import {
   setSubscriptionHandlers,
   beginSimulatedResourceUpdates,
   stopSimulatedResourceUpdates,
+  removeSubscriber,
 } from '../resources/subscriptions.js';
 
 describe('Resource Templates', () => {
@@ -324,4 +325,65 @@ describe('Subscriptions', () => {
       expect(true).toBe(true);
     });
   });
+
+  describe('removeSubscriber', () => {
+    const flushAsync = () => new Promise((resolve) => setTimeout(resolve, 10));
+
+    it('should stop sending resource update notifications to a removed session', async () => {
+      const notification = vi.fn();
+      const setRequestHandler = vi.fn();
+      const mockServer = {
+        server: { setRequestHandler, notification },
+        sendLoggingMessage: vi.fn(),
+      } as unknown as McpServer;
+
+      setSubscriptionHandlers(mockServer);
+      const subscribeHandler = setRequestHandler.mock.calls[0][1];
+
+      const uri = 'demo://resource/dynamic/text/removeSubscriber-1';
+      await subscribeHandler(
+        { params: { uri } },
+        { sessionId: 'session-removed' }
+      );
+
+      removeSubscriber('session-removed');
+
+      beginSimulatedResourceUpdates(mockServer, 'session-removed');
+      await flushAsync();
+
+      expect(notification).not.toHaveBeenCalled();
+
+      stopSimulatedResourceUpdates('session-removed');
+    });
+
+    it('should leave other sessions subscribed to the same URI unaffected', async () => {
+      const notification = vi.fn();
+      const setRequestHandler = vi.fn();
+      const mockServer = {
+        server: { setRequestHandler, notification },
+        sendLoggingMessage: vi.fn(),
+      } as unknown as McpServer;
+
+      setSubscriptionHandlers(mockServer);
+      const subscribeHandler = setRequestHandler.mock.calls[0][1];
+
+      const uri = 'demo://resource/dynamic/text/removeSubscriber-2';
+      await subscribeHandler({ params: { uri } }, { sessionId: 'session-a' });
+      await subscribeHandler({ params: { uri } }, { sessionId: 'session-b' });
+
+      removeSubscriber('session-a');
+
+      beginSimulatedResourceUpdates(mockServer, 'session-b');
+      await flushAsync();
+
+      expect(notification).toHaveBeenCalledWith(
+        expect.objectContaining({
+          method: 'notifications/resources/updated',
+          params: { uri },
+        })
+      );
+
+      stopSimulatedResourceUpdates('session-b');
+    });
+  });
 });
diff --git a/src/everything/resources/subscriptions.ts b/src/everything/resources/subscriptions.ts
index 854a8633a2..9d2044147c 100644
--- a/src/everything/resources/subscriptions.ts
+++ b/src/everything/resources/subscriptions.ts
@@ -166,3 +166,22 @@ export const stopSimulatedResourceUpdates = (sessionId?: string) => {
     subsUpdateIntervals.delete(sessionId);
   }
 };
+
+/**
+ * Removes a session from every URI's subscriber set, dropping any URI entry
+ * that ends up with no remaining subscribers.
+ *
+ * A session that disconnects without explicitly unsubscribing otherwise stays
+ * in `subscriptions` for the life of the process. Call this from the
+ * transport's `cleanup(sessionId)` when a session ends.
+ *
+ * @param {string} [sessionId]
+ */
+export const removeSubscriber = (sessionId?: string) => {
+  for (const [uri, subscribers] of subscriptions) {
+    subscribers.delete(sessionId);
+    if (subscribers.size === 0) {
+      subscriptions.delete(uri);
+    }
+  }
+};
diff --git a/src/everything/server/index.ts b/src/everything/server/index.ts
index f1459cc812..182a5a084a 100644
--- a/src/everything/server/index.ts
+++ b/src/everything/server/index.ts
@@ -6,6 +6,7 @@ import {
 import {
   setSubscriptionHandlers,
   stopSimulatedResourceUpdates,
+  removeSubscriber,
 } from "../resources/subscriptions.js";
 import { registerConditionalTools, registerTools } from "../tools/index.js";
 import { registerResources, readInstructions } from "../resources/index.js";
@@ -110,6 +111,8 @@ export const createServer: () => ServerFactoryResponse = () => {
       // Stop any simulated logging or resource updates that may have been initiated.
       stopSimulatedLogging(sessionId);
       stopSimulatedResourceUpdates(sessionId);
+      // Drop this session from any resource subscriptions it left open.
+      removeSubscriber(sessionId);
       // Clean up task store timers
       taskStore.cleanup();
       if (initializeTimeout) clearTimeout(initializeTimeout);