Enable, disable, update, and remove MCP tools at runtime (tools listChanged) with the TypeScript SDK

Documented steps

1. Use @modelcontextprotocol/server v2. Keep the handle returned by registerTool — it is a RegisteredTool object: const report = server.registerTool('run-report', { description: 'Run the weekly report' }, async () => ({ content: [{ type: 'text', text: 'queued' }] }));
2. Update metadata at runtime with report.update({ description: '...' }) — this mutates the registration AND automatically sends notifications/tools/list_changed.
3. Hide/restore a tool with report.disable() / report.enable() — a disabled tool disappears from tools/list and calls to it fail, without deleting the registration. Remove permanently with report.remove().
4. Do NOT also call sendToolListChanged() for these mutations — every mutation through the handle sends the matching list-changed notification on its own. Call server.sendToolListChanged() directly only when the tool set changes for a reason the registration API cannot observe (e.g. external config reload).
5. If serving over Streamable HTTP via createMcpHandler, the McpServer instance is per-request: publish notifications through handler.notify.toolsChanged() (also .promptsChanged() / .resourcesChanged() / .resourceUpdated(uri)) instead of instance methods. Over stdio, serveStdio routes the instance's own notifications correctly. Docs: https://raw.githubusercontent.com/modelcontextprotocol/typescript-sdk/main/docs/servers/notifications.md