From 95383c79482d8149c261a5a1ce018bace310a7cd Mon Sep 17 00:00:00 2001
From: Serhii Lizunov <34252204+LizunovSergey@users.noreply.github.com>
Date: Sat, 8 Aug 2026 20:18:46 +0200
Subject: [PATCH 1/2] fix(server): preserve explicit tool listChanged
 capability

---
 src/server/index.ts     |  5 ++++-
 src/server/mcp.ts       |  2 +-
 test/server/mcp.test.ts | 47 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/src/server/index.ts b/src/server/index.ts
index cd75e5954a..8b39d10772 100644
--- a/src/server/index.ts
+++ b/src/server/index.ts
@@ -445,7 +445,10 @@ export class Server<
         return this._clientVersion;
     }
 
-    private getCapabilities(): ServerCapabilities {
+    /**
+     * Returns the current server capabilities.
+     */
+    public getCapabilities(): ServerCapabilities {
         return this._capabilities;
     }
 
diff --git a/src/server/mcp.ts b/src/server/mcp.ts
index 9fe0ed549c..cc8e5f99f7 100644
--- a/src/server/mcp.ts
+++ b/src/server/mcp.ts
@@ -131,7 +131,7 @@ export class McpServer {
 
         this.server.registerCapabilities({
             tools: {
-                listChanged: true
+                listChanged: this.server.getCapabilities().tools?.listChanged ?? true
             }
         });
 
diff --git a/test/server/mcp.test.ts b/test/server/mcp.test.ts
index 575d6a300e..6420ac8aa5 100644
--- a/test/server/mcp.test.ts
+++ b/test/server/mcp.test.ts
@@ -56,6 +56,53 @@ describe.each(zodTestMatrix)('$zodVersionLabel', (entry: ZodMatrixEntry) => {
             expect(mcpServer.server).toBeDefined();
         });
 
+        test('should preserve an explicitly disabled tool listChanged capability', async () => {
+            const mcpServer = new McpServer(
+                {
+                    name: 'test server',
+                    version: '1.0'
+                },
+                {
+                    capabilities: {
+                        tools: { listChanged: false }
+                    }
+                }
+            );
+            const client = new Client({
+                name: 'test client',
+                version: '1.0'
+            });
+
+            mcpServer.registerTool('test', {}, async () => ({
+                content: [{ type: 'text', text: 'Test response' }]
+            }));
+
+            const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair();
+            await Promise.all([client.connect(clientTransport), mcpServer.connect(serverTransport)]);
+
+            expect(client.getServerCapabilities()?.tools?.listChanged).toBe(false);
+        });
+
+        test('should enable the tool listChanged capability by default', async () => {
+            const mcpServer = new McpServer({
+                name: 'test server',
+                version: '1.0'
+            });
+            const client = new Client({
+                name: 'test client',
+                version: '1.0'
+            });
+
+            mcpServer.registerTool('test', {}, async () => ({
+                content: [{ type: 'text', text: 'Test response' }]
+            }));
+
+            const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair();
+            await Promise.all([client.connect(clientTransport), mcpServer.connect(serverTransport)]);
+
+            expect(client.getServerCapabilities()?.tools?.listChanged).toBe(true);
+        });
+
         /***
          * Test: Notification Sending via Server
          */

From 15cf0fa0a6f7ab3333c894b0f1e77dd641ca3759 Mon Sep 17 00:00:00 2001
From: Serhii Lizunov <34252204+LizunovSergey@users.noreply.github.com>
Date: Sat, 8 Aug 2026 20:36:37 +0200
Subject: [PATCH 2/2] chore: add changeset for listChanged fix

---
 .changeset/preserve-tool-list-changed.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/preserve-tool-list-changed.md

diff --git a/.changeset/preserve-tool-list-changed.md b/.changeset/preserve-tool-list-changed.md
new file mode 100644
index 0000000000..70eae53e80
--- /dev/null
+++ b/.changeset/preserve-tool-list-changed.md
@@ -0,0 +1,5 @@
+---
+'@modelcontextprotocol/sdk': patch
+---
+
+Preserve an explicitly configured `tools.listChanged` capability when registering tools with `McpServer`.