chore: import upstream snapshot with attribution

apps/sim/app/api/mcp/events/route.ts

@@ -0,0 +1,62 @@
+/**
+ * SSE endpoint for MCP tool-change events.
+ *
+ * Pushes `tools_changed` events to the browser when:
+ *  - An external MCP server sends `notifications/tools/list_changed` (via connection manager)
+ *  - A workflow CRUD route modifies workflow MCP server tools (via pub/sub)
+ *
+ * Auth is handled via session cookies (EventSource sends cookies automatically).
+ */
+
+import type { NextRequest } from 'next/server'
+import { mcpEventsQuerySchema } from '@/lib/api/contracts/mcp'
+import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
+import { createWorkspaceSSE } from '@/lib/events/sse-endpoint'
+import { mcpConnectionManager } from '@/lib/mcp/connection-manager'
+import { mcpPubSub } from '@/lib/mcp/pubsub'
+
+export const dynamic = 'force-dynamic'
+
+const mcpEventsHandler = createWorkspaceSSE({
+  label: 'mcp-events',
+  subscriptions: [
+    {
+      subscribe: (workspaceId, send) => {
+        if (!mcpConnectionManager) return () => {}
+        return mcpConnectionManager.subscribe((event) => {
+          if (event.workspaceId !== workspaceId) return
+          send('tools_changed', {
+            source: 'external',
+            serverId: event.serverId,
+            timestamp: event.timestamp,
+          })
+        })
+      },
+    },
+    {
+      subscribe: (workspaceId, send) => {
+        if (!mcpPubSub) return () => {}
+        return mcpPubSub.onWorkflowToolsChanged((event) => {
+          if (event.workspaceId !== workspaceId) return
+          send('tools_changed', {
+            source: 'workflow',
+            serverId: event.serverId,
+            timestamp: Date.now(),
+          })
+        })
+      },
+    },
+  ],
+})
+
+export const GET = withRouteHandler(async (request: NextRequest) => {
+  const queryValidation = mcpEventsQuerySchema.safeParse({
+    workspaceId: request.nextUrl.searchParams.get('workspaceId'),
+  })
+
+  if (!queryValidation.success || !queryValidation.data.workspaceId) {
+    return new Response('Missing workspaceId query parameter', { status: 400 })
+  }
+
+  return mcpEventsHandler(request)
+})