feat(desktop): reattach popped-out agent activity

Allow detached agent activity windows to hand their session back to the main window through the URL-backed agent session panel state, with a durable localStorage fallback for cross-window delivery.

desktop/src/app/AppShell.tsx

@@ -19,6 +19,7 @@ import { useBackForwardControls } from "@/app/navigation/useBackForwardControls"
 import { useLiveHomeFeedActions } from "@/app/useLiveHomeFeedActions";
 import { useMarkAsReadShortcuts } from "@/app/useMarkAsReadShortcuts";
 import { useSettingsShortcuts } from "@/app/useSettingsShortcuts";
+import { useAgentWindowAttachRequests } from "@/app/useAgentWindowAttachRequests";
 import { useThreadActivityFeedItems } from "@/app/useThreadActivityFeedItems";
 import { useWebviewZoomShortcuts } from "@/app/useWebviewZoomShortcuts";
 import {
@@ -535,9 +536,8 @@ export function AppShell() {
     },
   );
 
-  // Prevent webview file:/// navigation on file drop outside the composer.
-  // Scoped to file drags only (text drag-and-drop into inputs still works).
-  // Composer's onDrop fires first (React synthetic before window bubble).
+  useAgentWindowAttachRequests(goChannel);
+
   React.useEffect(() => {
     function preventNavigation(e: DragEvent) {
       if (e.dataTransfer?.types.includes("Files")) {

desktop/src/app/navigation/useAppNavigation.ts

@@ -133,6 +133,7 @@ export function useAppNavigation() {
     (
       channelId: string,
       options?: {
+        agentSession?: string;
         messageId?: string;
         replace?: boolean;
         threadRootId?: string | null;
@@ -146,10 +147,15 @@ export function useAppNavigation() {
           },
           search: options?.messageId
             ? {
+                agentSession: options.agentSession,
                 messageId: options.messageId,
                 threadRootId: options.threadRootId ?? undefined,
               }
-            : {},
+            : options?.agentSession
+              ? {
+                  agentSession: options.agentSession,
+                }
+              : {},
         },
         {
           replace: options?.replace,

desktop/src/app/routes.ts

@@ -2,7 +2,6 @@ import { index, rootRoute, route } from "@tanstack/virtual-file-routes";
 
 export const routes = rootRoute("root.tsx", [
   index("index.tsx"),
-  route("/agent-window", "agent-window.tsx"),
   route("/agents", "agents.tsx"),
   route("/pulse", "pulse.tsx"),
   route("/reminders", "reminders.tsx"),

desktop/src/app/routes/agent-window.tsx

@@ -1,4 +1,4 @@
-import { createFileRoute } from "@tanstack/react-router";
+import { useRouterState } from "@tanstack/react-router";
 
 import { AgentWindowScreen } from "@/features/agents/ui/AgentWindowScreen";
 import type { ChannelType } from "@/shared/api/types";
@@ -32,14 +32,12 @@ function validateAgentWindowSearch(
   };
 }
 
-export const Route = createFileRoute("/agent-window")({
-  validateSearch: validateAgentWindowSearch,
-  component: AgentWindowRouteComponent,
-});
-
-function AgentWindowRouteComponent() {
+export function AgentWindowRouteComponent() {
+  const search = useRouterState({
+    select: (state) => state.location.search as Record<string, unknown>,
+  });
   const { channelId, pubkey, name, channelName, channelType } =
-    Route.useSearch();
+    validateAgentWindowSearch(search);
 
   if (!channelId || !pubkey) {
     return (

desktop/src/app/routes/root.tsx

@@ -1,10 +1,7 @@
-import {
-  Outlet,
-  createRootRoute,
-  useRouterState,
-} from "@tanstack/react-router";
+import { createRootRoute, useRouterState } from "@tanstack/react-router";
 
 import { AppShell } from "@/app/AppShell";
+import { AgentWindowRouteComponent } from "@/app/routes/agent-window";
 
 /**
  * Popped-out agent conversation windows load the same frontend at
@@ -20,7 +17,7 @@ function RootComponent() {
   if (pathname.startsWith("/agent-window")) {
     return (
       <div className="flex h-dvh flex-col overflow-hidden bg-background text-foreground">
-        <Outlet />
+        <AgentWindowRouteComponent />
       </div>
     );
   }

desktop/src/app/useAgentWindowAttachRequests.ts

@@ -0,0 +1,119 @@
+import * as React from "react";
+import { listen } from "@tauri-apps/api/event";
+
+import {
+  AGENT_WINDOW_ATTACH_EVENT,
+  AGENT_WINDOW_ATTACH_STORAGE_KEY,
+  type AgentWindowAttachRequest,
+} from "@/features/agents/lib/openAgentConversationWindow";
+import { revealDesktopAppWindow } from "@/features/notifications/lib/desktop";
+
+type GoChannelWithAgentSession = (
+  channelId: string,
+  options?: { agentSession?: string },
+) => Promise<unknown>;
+
+function isAgentWindowAttachRequest(
+  payload: unknown,
+): payload is AgentWindowAttachRequest {
+  return (
+    typeof payload === "object" &&
+    payload !== null &&
+    "agentPubkey" in payload &&
+    "channelId" in payload &&
+    typeof payload.agentPubkey === "string" &&
+    payload.agentPubkey.length > 0 &&
+    typeof payload.channelId === "string" &&
+    payload.channelId.length > 0
+  );
+}
+
+function parseAgentWindowAttachRequest(
+  raw: string | null,
+): AgentWindowAttachRequest | null {
+  if (!raw) {
+    return null;
+  }
+
+  try {
+    const payload = JSON.parse(raw) as unknown;
+    return isAgentWindowAttachRequest(payload) ? payload : null;
+  } catch {
+    return null;
+  }
+}
+
+export function useAgentWindowAttachRequests(
+  goChannel: GoChannelWithAgentSession,
+) {
+  const handleAgentWindowAttachRequest = React.useEffectEvent(
+    async (payload: unknown) => {
+      if (!isAgentWindowAttachRequest(payload)) {
+        return;
+      }
+
+      window.localStorage.removeItem(AGENT_WINDOW_ATTACH_STORAGE_KEY);
+      await revealDesktopAppWindow();
+      await goChannel(payload.channelId, {
+        agentSession: payload.agentPubkey,
+      });
+    },
+  );
+
+  const consumePendingAgentWindowAttachRequest = React.useEffectEvent(() => {
+    const payload = parseAgentWindowAttachRequest(
+      window.localStorage.getItem(AGENT_WINDOW_ATTACH_STORAGE_KEY),
+    );
+    if (!payload) {
+      return;
+    }
+
+    void handleAgentWindowAttachRequest(payload);
+  });
+
+  React.useEffect(() => {
+    let isCancelled = false;
+    let unlisten: (() => void) | null = null;
+
+    consumePendingAgentWindowAttachRequest();
+
+    function handleStorage(event: StorageEvent) {
+      if (
+        event.storageArea !== window.localStorage ||
+        event.key !== AGENT_WINDOW_ATTACH_STORAGE_KEY
+      ) {
+        return;
+      }
+
+      const payload = parseAgentWindowAttachRequest(event.newValue);
+      if (payload) {
+        void handleAgentWindowAttachRequest(payload);
+      }
+    }
+
+    function handleFocus() {
+      consumePendingAgentWindowAttachRequest();
+    }
+
+    window.addEventListener("storage", handleStorage);
+    window.addEventListener("focus", handleFocus);
+
+    void listen<unknown>(AGENT_WINDOW_ATTACH_EVENT, (event) => {
+      void handleAgentWindowAttachRequest(event.payload);
+    }).then((dispose) => {
+      if (isCancelled) {
+        dispose();
+        return;
+      }
+
+      unlisten = dispose;
+    });
+
+    return () => {
+      isCancelled = true;
+      window.removeEventListener("storage", handleStorage);
+      window.removeEventListener("focus", handleFocus);
+      unlisten?.();
+    };
+  }, []);
+}

desktop/src/features/agents/lib/openAgentConversationWindow.ts

@@ -14,6 +14,14 @@ export type OpenAgentConversationWindowInput = {
   observerEvents?: readonly ObserverEvent[];
 };
 
+export const AGENT_WINDOW_ATTACH_EVENT = "agent-window-attach-request";
+export const AGENT_WINDOW_ATTACH_STORAGE_KEY = "buzz:agent-window-attach";
+
+export type AgentWindowAttachRequest = {
+  agentPubkey: string;
+  channelId: string;
+};
+
 const DEFAULT_WIDTH = 460;
 const DEFAULT_HEIGHT = 680;
 const MIN_WIDTH = 380;

desktop/src/features/agents/ui/AgentWindowScreen.tsx

@@ -1,5 +1,9 @@
 import * as React from "react";
-import { CircleDot, Octagon } from "lucide-react";
+import { isTauri } from "@tauri-apps/api/core";
+import { emit } from "@tauri-apps/api/event";
+import { getCurrentWebviewWindow } from "@tauri-apps/api/webviewWindow";
+import { Window } from "@tauri-apps/api/window";
+import { CircleDot, Octagon, PanelRightOpen } from "lucide-react";
 import { toast } from "sonner";
 
 import {
@@ -11,7 +15,12 @@ import {
   useActiveAgentTurnsBridge,
 } from "@/features/agents/activeAgentTurnsStore";
 import { isManagedAgentActive } from "@/features/agents/lib/managedAgentControlActions";
-import { agentConversationSeedStorageKey } from "@/features/agents/lib/openAgentConversationWindow";
+import {
+  AGENT_WINDOW_ATTACH_EVENT,
+  AGENT_WINDOW_ATTACH_STORAGE_KEY,
+  agentConversationSeedStorageKey,
+  type AgentWindowAttachRequest,
+} from "@/features/agents/lib/openAgentConversationWindow";
 import {
   seedAgentObserverEvents,
   useManagedAgentObserverBridge,
@@ -241,6 +250,37 @@ export function AgentWindowScreen({
     }
   }
 
+  async function handleAttachToMainWindow() {
+    if (!isTauri()) {
+      window.location.hash = `/channels/${encodeURIComponent(
+        channelId,
+      )}?agentSession=${encodeURIComponent(agentPubkey)}`;
+      return;
+    }
+
+    try {
+      const payload: AgentWindowAttachRequest = { agentPubkey, channelId };
+      window.localStorage.setItem(
+        AGENT_WINDOW_ATTACH_STORAGE_KEY,
+        JSON.stringify({ ...payload, writtenAt: Date.now() }),
+      );
+      await emit(AGENT_WINDOW_ATTACH_EVENT, payload);
+
+      const mainWindow = await Window.getByLabel("main");
+      await mainWindow?.unminimize().catch(() => {});
+      await mainWindow?.show().catch(() => {});
+      await mainWindow?.setFocus().catch(() => {});
+
+      await getCurrentWebviewWindow().close();
+    } catch (error) {
+      toast.error(
+        error instanceof Error
+          ? error.message
+          : "Failed to attach this activity to the main window.",
+      );
+    }
+  }
+
   const isLive = isManagedAgentActive(sessionAgent);
 
   return (
@@ -297,6 +337,25 @@ export function AgentWindowScreen({
             </TooltipContent>
           </Tooltip>
         ) : null}
+        <Tooltip>
+          <TooltipTrigger asChild>
+            <Button
+              aria-label="Attach activity to main window"
+              data-testid="agent-window-attach"
+              onClick={() => {
+                void handleAttachToMainWindow();
+              }}
+              size="icon"
+              type="button"
+              variant="ghost"
+            >
+              <PanelRightOpen className="h-4 w-4" />
+            </Button>
+          </TooltipTrigger>
+          <TooltipContent side="bottom" className="text-xs">
+            Attach activity to the main window.
+          </TooltipContent>
+        </Tooltip>
       </header>
 
       <div

desktop/src/features/channels/ui/ChannelPane.tsx

@@ -924,6 +924,14 @@ export const ChannelPane = React.memo(function ChannelPane({
                       onOpenProfilePanel(selectedAgent.pubkey)
                     }
                     onClose={onCloseAgentSession}
+                    onOpenWindow={
+                      onOpenAgentWindow
+                        ? () => {
+                            onOpenAgentWindow(selectedAgent.pubkey);
+                            onCloseAgentSession();
+                          }
+                        : undefined
+                    }
                     widthPx={threadPanelWidthPx}
                   />
                 );