feat(memory-graph): add onNodeSelect callback for selection changes (#1350)

packages/memory-graph/README.md

@@ -66,6 +66,7 @@ function App() {
 | `error` | `Error \| null` | Error to display |
 | `loadMoreDocuments` | `() => Promise<void>` | Function to load more data |
 | `highlightDocumentIds` | `string[]` | IDs of documents to highlight |
+| `onNodeSelect` | `(nodeId: string \| null) => void` | Called when the selected node changes (click, keyboard, slideshow, or cleared) |
 
 Console mode uses the supplied theme colors for its surface, 16px dot grid, document icons, and node fills and strokes. Consumer mode keeps its transparent surface and cluster colors.
 

packages/memory-graph/src/components/memory-graph.tsx

@@ -73,6 +73,7 @@ export function MemoryGraph({
 	colors: colorOverrides,
 	totalCount,
 	onOpenDocument: externalOnOpenDocument,
+	onNodeSelect,
 	labels: labelOverrides,
 	layering,
 	appearance,
@@ -97,6 +98,15 @@ export function MemoryGraph({
 	// React state only for things that affect DOM
 	const [hoveredNode, setHoveredNode] = useState<string | null>(null)
 	const [selectedNode, setSelectedNode] = useState<string | null>(null)
+	const onNodeSelectRef = useRef(onNodeSelect)
+	onNodeSelectRef.current = onNodeSelect
+	const lastSelectedRef = useRef(selectedNode)
+	// Compares against the last value so mount and StrictMode re-runs do not emit.
+	useEffect(() => {
+		if (lastSelectedRef.current === selectedNode) return
+		lastSelectedRef.current = selectedNode
+		onNodeSelectRef.current?.(selectedNode)
+	}, [selectedNode])
 	const [zoomDisplay, setZoomDisplay] = useState(50)
 	// Monotonic counter that increments on any viewport change (pan or zoom)
 	// Used as a dependency proxy to recalculate popover positions

packages/memory-graph/src/types.ts

@@ -226,6 +226,8 @@ export interface MemoryGraphProps {
 	totalCount?: number
 	/** Callback when user wants to view full document content */
 	onOpenDocument?: (documentId: string) => void
+	/** Called when the selected node changes; null when cleared */
+	onNodeSelect?: (nodeId: string | null) => void
 	/** Custom user-facing labels (partial) - merged with defaults */
 	labels?: MemoryGraphLabels
 	/** Overlay layering controls */