diff --git a/understand-anything-plugin/packages/dashboard/src/App.tsx b/understand-anything-plugin/packages/dashboard/src/App.tsx
index 8abc0e8..4aed9bf 100644
--- a/understand-anything-plugin/packages/dashboard/src/App.tsx
+++ b/understand-anything-plugin/packages/dashboard/src/App.tsx
@@ -109,6 +109,10 @@ function Dashboard({ accessToken }: { accessToken: string }) {
   const togglePathFinder = useDashboardStore((s) => s.togglePathFinder);
   const nodeTypeFilters = useDashboardStore((s) => s.nodeTypeFilters);
   const toggleNodeTypeFilter = useDashboardStore((s) => s.toggleNodeTypeFilter);
+  const detailLevel = useDashboardStore((s) => s.detailLevel);
+  const setDetailLevel = useDashboardStore((s) => s.setDetailLevel);
+  const showFunctionsInClassView = useDashboardStore((s) => s.showFunctionsInClassView);
+  const toggleShowFunctionsInClassView = useDashboardStore((s) => s.toggleShowFunctionsInClassView);
   const [loadError, setLoadError] = useState<string | null>(null);
   const [graphIssues, setGraphIssues] = useState<GraphIssue[]>([]);
   const [showKeyboardHelp, setShowKeyboardHelp] = useState(false);
@@ -443,6 +447,52 @@ function Dashboard({ accessToken }: { accessToken: string }) {
         <div className="flex-1 min-w-0 overflow-x-auto scrollbar-hide">
           <div className="flex items-center gap-4 w-max">
             <DiffToggle />
+            {/* Detail level: file view (architecture) / class view (code structure) */}
+            {!isKnowledgeGraph && viewMode !== "domain" && (
+              <>
+                <div className="w-px h-5 bg-border-subtle" />
+                <div className="flex items-center bg-elevated rounded-lg p-0.5">
+                  <button
+                    type="button"
+                    onClick={() => setDetailLevel("file")}
+                    title="Files only — architecture-level dependencies (fast)"
+                    className={`px-3 py-1 text-xs font-medium rounded-md transition-colors ${
+                      detailLevel === "file"
+                        ? "bg-accent/20 text-accent"
+                        : "text-text-muted hover:text-text-secondary"
+                    }`}
+                  >
+                    Files
+                  </button>
+                  <button
+                    type="button"
+                    onClick={() => setDetailLevel("class")}
+                    title="Files + Classes — code structure with inheritance"
+                    className={`px-3 py-1 text-xs font-medium rounded-md transition-colors ${
+                      detailLevel === "class"
+                        ? "bg-accent/20 text-accent"
+                        : "text-text-muted hover:text-text-secondary"
+                    }`}
+                  >
+                    +Classes
+                  </button>
+                </div>
+                {detailLevel === "class" && (
+                  <button
+                    type="button"
+                    onClick={toggleShowFunctionsInClassView}
+                    title="Toggle function nodes (may slow down rendering)"
+                    className={`text-[10px] font-semibold uppercase tracking-wider px-2 py-1 rounded border transition-colors ${
+                      showFunctionsInClassView
+                        ? "border-amber-500/50 bg-amber-500/10 text-amber-400"
+                        : "border-border-medium bg-elevated text-text-muted hover:text-text-secondary"
+                    }`}
+                  >
+                    fn
+                  </button>
+                )}
+              </>
+            )}
             <div className="flex items-center gap-1">
               {(isKnowledgeGraph ? [
                 { key: "knowledge" as const, label: "All", color: "var(--color-node-article)" },
diff --git a/understand-anything-plugin/packages/dashboard/src/components/GraphView.tsx b/understand-anything-plugin/packages/dashboard/src/components/GraphView.tsx
index 4ba8d1b..2a5037a 100644
--- a/understand-anything-plugin/packages/dashboard/src/components/GraphView.tsx
+++ b/understand-anything-plugin/packages/dashboard/src/components/GraphView.tsx
@@ -366,6 +366,7 @@ function useLayerDetailTopology(): LayerDetailTopology & {
   layoutStatus: "computing" | "ready";
 } {
   const graph = useDashboardStore((s) => s.graph);
+  const nodesById = useDashboardStore((s) => s.nodesById);
   const activeLayerId = useDashboardStore((s) => s.activeLayerId);
   const selectNode = useDashboardStore((s) => s.selectNode);
   const persona = useDashboardStore((s) => s.persona);
@@ -375,6 +376,8 @@ function useLayerDetailTopology(): LayerDetailTopology & {
   const focusNodeId = useDashboardStore((s) => s.focusNodeId);
   const nodeTypeFilters = useDashboardStore((s) => s.nodeTypeFilters);
   const drillIntoLayer = useDashboardStore((s) => s.drillIntoLayer);
+  const detailLevel = useDashboardStore((s) => s.detailLevel);
+  const showFunctionsInClassView = useDashboardStore((s) => s.showFunctionsInClassView);
 
   const handleNodeSelect = useCallback(
     (nodeId: string) => {
@@ -404,10 +407,20 @@ function useLayerDetailTopology(): LayerDetailTopology & {
 
     // Expand layer membership to include sub-file nodes (function/class)
     // whose parent file is in this layer. Joined via "contains" edges.
+    // File view: file nodes only (architecture-level dependencies).
+    // Class view: file nodes + class nodes, functions only when toggle is on.
     const expandedLayerNodeIds = new Set(layerNodeIds);
-    for (const edge of graph.edges) {
-      if (edge.type === "contains" && layerNodeIds.has(edge.source)) {
-        expandedLayerNodeIds.add(edge.target);
+    if (detailLevel !== "file") {
+      for (const edge of graph.edges) {
+        if (edge.type === "contains" && layerNodeIds.has(edge.source)) {
+          const child = nodesById.get(edge.target);
+          if (!child) continue;
+          if (child.type === "class") {
+            expandedLayerNodeIds.add(edge.target);
+          } else if (child.type === "function" && showFunctionsInClassView) {
+            expandedLayerNodeIds.add(edge.target);
+          }
+        }
       }
     }
 
@@ -626,6 +639,7 @@ function useLayerDetailTopology(): LayerDetailTopology & {
     };
   }, [
     graph,
+    nodesById,
     activeLayerId,
     persona,
     diffMode,
@@ -634,6 +648,8 @@ function useLayerDetailTopology(): LayerDetailTopology & {
     focusNodeId,
     nodeTypeFilters,
     drillIntoLayer,
+    detailLevel,
+    showFunctionsInClassView,
     handleNodeSelect,
     handleContainerToggle,
   ]);
diff --git a/understand-anything-plugin/packages/dashboard/src/store.ts b/understand-anything-plugin/packages/dashboard/src/store.ts
index ea398a1..b3b2a96 100644
--- a/understand-anything-plugin/packages/dashboard/src/store.ts
+++ b/understand-anything-plugin/packages/dashboard/src/store.ts
@@ -15,6 +15,7 @@ export type NodeType = "file" | "function" | "class" | "module" | "concept" | "c
 export type Complexity = "simple" | "moderate" | "complex";
 export type EdgeCategory = "structural" | "behavioral" | "data-flow" | "dependencies" | "semantic" | "infrastructure" | "domain" | "knowledge";
 export type ViewMode = "structural" | "domain" | "knowledge";
+export type DetailLevel = "file" | "class";
 
 export interface FilterState {
   nodeTypes: Set<NodeType>;
@@ -146,6 +147,13 @@ interface DashboardStore {
   nodeTypeFilters: Record<NodeCategory, boolean>;
   toggleNodeTypeFilter: (category: NodeCategory) => void;
 
+  // Detail level: "file" shows only file nodes (architecture view),
+  // "class" shows files + class nodes (code structure view) with optional function expansion.
+  detailLevel: DetailLevel;
+  setDetailLevel: (level: DetailLevel) => void;
+  showFunctionsInClassView: boolean;
+  toggleShowFunctionsInClassView: () => void;
+
   setGraph: (graph: KnowledgeGraph) => void;
   selectNode: (nodeId: string | null) => void;
   navigateToNode: (nodeId: string) => void;
@@ -331,6 +339,29 @@ export const useDashboardStore = create<DashboardStore>()((set, get) => ({
       pendingFocusContainer: null,
     })),
 
+  detailLevel: "file",
+  setDetailLevel: (level) =>
+    set({
+      detailLevel: level,
+      // Detail level changes which nodes are visible; cached positions stale.
+      // Reset fn toggle so it doesn't resurrect when re-entering class view.
+      showFunctionsInClassView: false,
+      containerLayoutCache: new Map(),
+      containerSizeMemory: new Map(),
+      expandedContainers: new Set(),
+      pendingFocusContainer: null,
+    }),
+
+  showFunctionsInClassView: false,
+  toggleShowFunctionsInClassView: () =>
+    set((state) => ({
+      showFunctionsInClassView: !state.showFunctionsInClassView,
+      containerLayoutCache: new Map(),
+      containerSizeMemory: new Map(),
+      expandedContainers: new Set(),
+      pendingFocusContainer: null,
+    })),
+
   setGraph: (graph) => {
     const searchEngine = new SearchEngine(graph.nodes);
     const query = get().searchQuery;