docs: document tool list changed notifications

docs/server.md

@@ -201,6 +201,25 @@ server.registerTool(
 
 If a handler throws instead of returning `isError`, the SDK catches the exception and converts it to `{ isError: true }` automatically — so an explicit try/catch is optional but gives you control over the error message. When `isError` is true, output schema validation is skipped.
 
+### List changed notifications
+
+When the set of available tools changes at runtime, the server should notify connected clients so they can refresh their tool list (see [List Changed Notification](https://spec.modelcontextprotocol.io/specification/2025-06-18/server/tools/#list-changed-notification) in the MCP specification).
+
+{@linkcode @modelcontextprotocol/server!server/mcp.McpServer#registerTool | registerTool} sends this notification automatically when called after the client is already connected. To notify manually — for example, after removing a tool or toggling tool availability — call {@linkcode @modelcontextprotocol/server!server/mcp.McpServer#sendToolListChanged | sendToolListChanged}:
+
+```ts source="../examples/server/src/serverGuide.examples.ts#sendToolListChanged_basic"
+// Automatic: registering a tool at runtime sends the notification
+server.registerTool('new-tool', { description: 'A dynamically added tool' }, async () => ({
+    content: [{ type: 'text', text: 'done' }]
+}));
+
+// Manual: notify clients explicitly (e.g. after removing a tool)
+server.sendToolListChanged();
+```
+
+> [!NOTE]
+> On the client side, use the {@linkcode @modelcontextprotocol/client!client/client.ClientOptions | listChanged} option to automatically re-fetch tool lists when this notification arrives — see [Automatic list-change tracking](./client.md#automatic-list-change-tracking) in the client guide.
+
 ## Resources
 
 Resources expose read-only data — files, database schemas, configuration — that the host application can retrieve and attach as context for the model (see [Resources](https://modelcontextprotocol.io/docs/learn/server-concepts#resources) in the MCP overview). Unlike [tools](#tools), which the LLM invokes on its own, resources are application-controlled: the host decides which resources to fetch and how to present them.

examples/server/src/serverGuide.examples.ts

@@ -147,6 +147,19 @@ function registerTool_annotations(server: McpServer) {
     //#endregion registerTool_annotations
 }
 
+/** Example: Notifying clients when the tool list changes at runtime. */
+function sendToolListChanged_basic(server: McpServer) {
+    //#region sendToolListChanged_basic
+    // Automatic: registering a tool at runtime sends the notification
+    server.registerTool('new-tool', { description: 'A dynamically added tool' }, async () => ({
+        content: [{ type: 'text', text: 'done' }]
+    }));
+
+    // Manual: notify clients explicitly (e.g. after removing a tool)
+    server.sendToolListChanged();
+    //#endregion sendToolListChanged_basic
+}
+
 /** Example: Registering a static resource at a fixed URI. */
 function registerResource_static(server: McpServer) {
     //#region registerResource_static
@@ -540,6 +553,7 @@ void registerTool_basic;
 void registerTool_resourceLink;
 void registerTool_errorHandling;
 void registerTool_annotations;
+void sendToolListChanged_basic;
 void registerTool_logging;
 void registerTool_progress;
 void registerTool_sampling;