diff --git a/packages/agent-graph/src/ui/GraphControls.tsx b/packages/agent-graph/src/ui/GraphControls.tsx
index fb5806eb..884817d1 100644
--- a/packages/agent-graph/src/ui/GraphControls.tsx
+++ b/packages/agent-graph/src/ui/GraphControls.tsx
@@ -6,6 +6,7 @@
 import { useCallback } from 'react';
 import {
   Columns3,
+  Expand,
   Eye,
   EyeOff,
   Maximize2,
@@ -33,6 +34,7 @@ export interface GraphControlsProps {
   onZoomToFit: () => void;
   onRequestClose?: () => void;
   onRequestPinAsTab?: () => void;
+  onRequestFullscreen?: () => void;
   teamName: string;
   teamColor?: string;
   isAlive?: boolean;
@@ -46,6 +48,7 @@ export function GraphControls({
   onZoomToFit,
   onRequestClose,
   onRequestPinAsTab,
+  onRequestFullscreen,
   teamName,
   teamColor,
   isAlive,
@@ -133,6 +136,16 @@ export function GraphControls({
             />
           </>
         )}
+        {onRequestFullscreen && (
+          <>
+            <Separator />
+            <ToolbarButton
+              onClick={onRequestFullscreen}
+              icon={<Expand size={13} />}
+              label="Fullscreen"
+            />
+          </>
+        )}
         {onRequestClose && (
           <ToolbarButton onClick={onRequestClose} icon={<X size={13} />} />
         )}
diff --git a/packages/agent-graph/src/ui/GraphView.tsx b/packages/agent-graph/src/ui/GraphView.tsx
index bfac037f..4dec015f 100644
--- a/packages/agent-graph/src/ui/GraphView.tsx
+++ b/packages/agent-graph/src/ui/GraphView.tsx
@@ -31,6 +31,7 @@ export interface GraphViewProps {
   className?: string;
   onRequestClose?: () => void;
   onRequestPinAsTab?: () => void;
+  onRequestFullscreen?: () => void;
 }
 
 export function GraphView({
@@ -40,6 +41,7 @@ export function GraphView({
   className,
   onRequestClose,
   onRequestPinAsTab,
+  onRequestFullscreen,
 }: GraphViewProps): React.JSX.Element {
   // ─── React state (user-facing only) ─────────────────────────────────────
   const [selectedNodeId, setSelectedNodeId] = useState<string | null>(null);
@@ -327,6 +329,7 @@ export function GraphView({
         }}
         onRequestClose={onRequestClose}
         onRequestPinAsTab={onRequestPinAsTab}
+        onRequestFullscreen={onRequestFullscreen}
         teamName={data.teamName}
         teamColor={data.teamColor}
         isAlive={data.isAlive}
diff --git a/src/renderer/components/team/TeamDetailView.tsx b/src/renderer/components/team/TeamDetailView.tsx
index 4a01b5c0..878c9565 100644
--- a/src/renderer/components/team/TeamDetailView.tsx
+++ b/src/renderer/components/team/TeamDetailView.tsx
@@ -214,18 +214,46 @@ export const TeamDetailView = ({ teamName }: TeamDetailViewProps): React.JSX.Ele
     }
   }, [editorOpen, graphOpen]);
 
-  // Listen for Cmd+Shift+G keyboard shortcut
+  // Listen for Cmd+Shift+G keyboard shortcut — opens graph tab
   useEffect(() => {
     const handler = (e: Event) => {
       const detail = (e as CustomEvent).detail;
       if (detail?.teamName === teamName) {
-        setGraphOpen((prev) => !prev);
+        useStore.getState().openTab({
+          type: 'graph',
+          label: `${teamName} Graph`,
+          teamName,
+        });
       }
     };
     window.addEventListener('toggle-team-graph', handler);
     return () => window.removeEventListener('toggle-team-graph', handler);
   }, [teamName]);
 
+  // Listen for graph tab actions (open task, send message)
+  useEffect(() => {
+    const onOpenTask = (e: Event) => {
+      const { teamName: tn, taskId } = (e as CustomEvent).detail ?? {};
+      if (tn !== teamName || !data) return;
+      const task = data.tasks.find((t: { id: string }) => t.id === taskId);
+      if (task) setSelectedTask(task);
+    };
+    const onSendMsg = (e: Event) => {
+      const { teamName: tn, memberName } = (e as CustomEvent).detail ?? {};
+      if (tn !== teamName) return;
+      setSendDialogRecipient(memberName);
+      setSendDialogDefaultText(undefined);
+      setSendDialogDefaultChip(undefined);
+      setSendDialogOpen(true);
+    };
+    window.addEventListener('graph:open-task', onOpenTask);
+    window.addEventListener('graph:send-message', onSendMsg);
+    return () => {
+      window.removeEventListener('graph:open-task', onOpenTask);
+      window.removeEventListener('graph:send-message', onSendMsg);
+    };
+  });
+
   const [sendDialogOpen, setSendDialogOpen] = useState(false);
   const [deleteConfirmOpen, setDeleteConfirmOpen] = useState(false);
   const [stoppingTeam, setStoppingTeam] = useState(false);
@@ -1432,7 +1460,11 @@ export const TeamDetailView = ({ teamName }: TeamDetailViewProps): React.JSX.Ele
                   className="h-6 gap-1 px-2 text-xs text-[var(--color-text-muted)] hover:text-[var(--color-text)]"
                   onClick={(e) => {
                     e.stopPropagation();
-                    setGraphOpen(true);
+                    useStore.getState().openTab({
+                      type: 'graph',
+                      label: `${data.config.name} Graph`,
+                      teamName,
+                    });
                   }}
                 >
                   <Network size={12} />
diff --git a/src/renderer/features/agent-graph/ui/TeamGraphTab.tsx b/src/renderer/features/agent-graph/ui/TeamGraphTab.tsx
index 3238ea49..041bac55 100644
--- a/src/renderer/features/agent-graph/ui/TeamGraphTab.tsx
+++ b/src/renderer/features/agent-graph/ui/TeamGraphTab.tsx
@@ -1,8 +1,9 @@
 /**
  * TeamGraphTab — wraps GraphView for use as a dedicated tab.
+ * Provides Fullscreen button that opens the overlay.
  */
 
-import { useCallback } from 'react';
+import { useCallback, useState, lazy, Suspense } from 'react';
 
 import { GraphView } from '@claude-teams/agent-graph';
 
@@ -10,22 +11,73 @@ import { useTeamGraphAdapter } from '../adapters/useTeamGraphAdapter';
 
 import type { GraphDomainRef, GraphEventPort } from '@claude-teams/agent-graph';
 
+const TeamGraphOverlay = lazy(() =>
+  import('./TeamGraphOverlay').then((m) => ({ default: m.TeamGraphOverlay }))
+);
+
 export interface TeamGraphTabProps {
   teamName: string;
 }
 
 export const TeamGraphTab = ({ teamName }: TeamGraphTabProps): React.JSX.Element => {
   const graphData = useTeamGraphAdapter(teamName);
+  const [fullscreen, setFullscreen] = useState(false);
 
   const events: GraphEventPort = {
-    onNodeDoubleClick: useCallback((ref: GraphDomainRef) => {
-      console.log('Double-click in tab:', ref);
-    }, []),
+    onNodeDoubleClick: useCallback(
+      (ref: GraphDomainRef) => {
+        // Dispatch to TeamDetailView's dialog system via CustomEvent
+        if (ref.kind === 'task') {
+          window.dispatchEvent(
+            new CustomEvent('graph:open-task', { detail: { teamName, taskId: ref.taskId } })
+          );
+        } else if (ref.kind === 'member') {
+          window.dispatchEvent(
+            new CustomEvent('graph:send-message', {
+              detail: { teamName, memberName: ref.memberName },
+            })
+          );
+        }
+      },
+      [teamName]
+    ),
+    onSendMessage: useCallback(
+      (memberName: string) => {
+        window.dispatchEvent(
+          new CustomEvent('graph:send-message', { detail: { teamName, memberName } })
+        );
+      },
+      [teamName]
+    ),
+    onOpenTaskDetail: useCallback(
+      (taskId: string) => {
+        window.dispatchEvent(new CustomEvent('graph:open-task', { detail: { teamName, taskId } }));
+      },
+      [teamName]
+    ),
+    onOpenMemberProfile: useCallback(
+      (memberName: string) => {
+        window.dispatchEvent(
+          new CustomEvent('graph:send-message', { detail: { teamName, memberName } })
+        );
+      },
+      [teamName]
+    ),
   };
 
   return (
     <div className="size-full" style={{ background: '#050510' }}>
-      <GraphView data={graphData} events={events} className="size-full" />
+      <GraphView
+        data={graphData}
+        events={events}
+        className="size-full"
+        onRequestFullscreen={() => setFullscreen(true)}
+      />
+      {fullscreen && (
+        <Suspense fallback={null}>
+          <TeamGraphOverlay teamName={teamName} onClose={() => setFullscreen(false)} />
+        </Suspense>
+      )}
     </div>
   );
 };