diff --git a/backend/apps/agents/core/ws_manager.py b/backend/apps/agents/core/ws_manager.py
index 5b31aa54..b5ec0ee5 100644
--- a/backend/apps/agents/core/ws_manager.py
+++ b/backend/apps/agents/core/ws_manager.py
@@ -46,6 +46,8 @@ class ConnectionManager:
         self.active_dashboard_id: Optional[str] = None
         self.pending_futures: dict[str, asyncio.Future] = {}
         self.browser_futures: dict[str, asyncio.Future] = {}
+        # The Electron MAIN process (not the renderer) holds a single WS here. Cookie reads route to it so they don't ride the renderer, which macOS throttles when the window is backgrounded (the source of the session-borrow bridge's intermittent timeouts).
+        self.main_connection: Optional[WebSocket] = None
 
     async def connect_session(self, session_id: str, websocket: WebSocket):
         await websocket.accept()
@@ -57,6 +59,15 @@ class ConnectionManager:
         await websocket.accept()
         self.global_connections.append(websocket)
 
+    async def connect_main(self, websocket: WebSocket):
+        """Register the single Electron-main bridge socket (replaces any stale prior one)."""
+        await websocket.accept()
+        self.main_connection = websocket
+
+    def disconnect_main(self, websocket: WebSocket):
+        if self.main_connection is websocket:
+            self.main_connection = None
+
     def disconnect_session(self, session_id: str, websocket: WebSocket):
         if session_id in self.connections:
             self.connections[session_id] = [
@@ -213,11 +224,15 @@ class ConnectionManager:
     async def broadcast_global(self, event: str, data: dict):
         """Send to all dashboard connections; bypasses seq_log (dashboard resumes via full state refetch)."""
         payload = json.dumps({"event": event, "data": data})
+        dead: list[WebSocket] = []
         for ws in list(self.global_connections):
             try:
                 await ws.send_text(payload)
             except Exception:
-                pass
+                dead.append(ws)
+        # A renderer that reloaded without a clean close leaves a half-open socket here; a browser command broadcast into it is lost forever (the future then times out). Drop any socket that fails a send so the next command only targets live renderers.
+        for ws in dead:
+            self.disconnect_global(ws)
 
     async def send_approval_request(
         self, session_id: str, request_id: str, tool_name: str, tool_input: dict,
@@ -293,6 +308,27 @@ class ConnectionManager:
         finally:
             self.browser_futures.pop(request_id, None)
 
+    async def send_main_command(self, request_id: str, action: str, params: dict) -> dict:
+        """Send a command straight to the throttle-free Electron MAIN socket (cookie reads only); returns a not-connected error so the caller can fall back to the renderer."""
+        ws = self.main_connection
+        if ws is None:
+            return {"error": "Electron main bridge not connected"}
+        loop = asyncio.get_event_loop()
+        future = loop.create_future()
+        self.browser_futures[request_id] = future
+        payload = {"request_id": request_id, "action": action, "browser_id": "", "tab_id": "", "params": params}
+        try:
+            await ws.send_text(json.dumps({"event": "browser:command", "data": payload}))
+            done, _ = await asyncio.wait({future}, timeout=BROWSER_CMD_TIMEOUTS.get(action, BROWSER_CMD_TIMEOUT_DEFAULT))
+            if done:
+                return future.result()
+            return {"error": "Electron main bridge timed out"}
+        except Exception as e:
+            self.disconnect_main(ws)
+            return {"error": f"Electron main bridge send failed: {e}"}
+        finally:
+            self.browser_futures.pop(request_id, None)
+
     def resolve_browser_command(self, request_id: str, result: dict):
         """Resolve a pending browser command Future with the frontend's result."""
         future = self.browser_futures.get(request_id)
diff --git a/backend/main.py b/backend/main.py
index f493b22f..7c16cf89 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -363,6 +363,23 @@ async def websocket_dashboard(websocket: WebSocket):
         ws_manager.disconnect_global(websocket)
 
 
+@app.websocket("/ws/electron-main")
+async def websocket_electron_main(websocket: WebSocket):
+    """The Electron MAIN process (not the renderer) attaches here to serve partition-cookie
+    reads for the session-borrow bridge. Main doesn't throttle when the window is backgrounded,
+    so cookie reads over this socket don't hit the renderer's intermittent-timeout problem."""
+    if not p_ws_auth_ok(websocket):
+        return
+    await ws_manager.connect_main(websocket)
+    try:
+        while True:
+            msg = json.loads(await websocket.receive_text())
+            if msg.get("event") == "browser:result":
+                ws_manager.resolve_browser_command(msg.get("data", {}).get("request_id", ""), msg.get("data", {}))
+    except WebSocketDisconnect:
+        ws_manager.disconnect_main(websocket)
+
+
 @app.get("/api/dev/token")
 async def dev_token():
     """Hand the per-install token to the dev frontend, which has no Electron
@@ -508,19 +525,28 @@ P_SESSION_AUTH_COOKIES = {
 }
 
 
+async def p_read_session_cookies(domain: str) -> dict:
+    """Read a vetted platform's live partition cookies. Prefers the Electron MAIN bridge
+    (throttle-free) and falls back to the renderer when main hasn't attached or can't answer."""
+    if ws_manager.main_connection is not None:
+        result = await ws_manager.send_main_command(uuid4().hex, "get_session_cookies", {"domain": domain})
+        if not result.get("error"):
+            return result
+    return await ws_manager.send_browser_command(uuid4().hex, "get_session_cookies", "", {"domain": domain})
+
+
 @app.get("/api/browser-session/cookies")
 async def browser_session_cookies(domain: str = ""):
     """Hand a vetted platform's live partition cookies + UA to its own-session MCP shim.
 
     Auth is the standard localhost token (middleware). Cookies are read live from
-    Electron's persist:openswarm-browser partition via the dashboard bridge and are
-    never persisted server-side; the shim talks to the site as the user's browser.
+    Electron's persist:openswarm-browser partition and are never persisted server-side;
+    the shim talks to the site as the user's browser.
     """
     d = (domain or "").lower().strip().lstrip(".")
     if d not in P_SESSION_COOKIE_DOMAINS:
         return JSONResponse({"error": f"domain not allowed: {d or '(empty)'}", "cookies": []}, status_code=400)
-    rid = uuid4().hex
-    result = await ws_manager.send_browser_command(rid, "get_session_cookies", "", {"domain": d})
+    result = await p_read_session_cookies(d)
     if result.get("error"):
         return JSONResponse({"error": result["error"], "cookies": []})
     return JSONResponse({"cookies": result.get("cookies", []), "userAgent": result.get("userAgent", "")})
@@ -537,8 +563,7 @@ async def browser_session_status(domain: str = ""):
     d = (domain or "").lower().strip().lstrip(".")
     if d not in P_SESSION_COOKIE_DOMAINS:
         return JSONResponse({"error": f"domain not allowed: {d or '(empty)'}", "connected": False}, status_code=400)
-    rid = uuid4().hex
-    result = await ws_manager.send_browser_command(rid, "get_session_cookies", "", {"domain": d})
+    result = await p_read_session_cookies(d)
     if result.get("error"):
         return JSONResponse({"connected": False, "error": result["error"]})
     wanted = P_SESSION_AUTH_COOKIES.get(d, ())
diff --git a/electron/main.js b/electron/main.js
index e611a73e..30c138e0 100644
--- a/electron/main.js
+++ b/electron/main.js
@@ -1078,6 +1078,7 @@ function markBackendReady() {
     workflowsLifecycle.setBackend({ port: backendPort, token: authToken });
     workflowsLifecycle.startPolling();
   } catch (_) {}
+  try { connectMainBridge(); } catch (_) {}
 }
 
 function getAuthTokenFilePath() {
@@ -2778,7 +2779,7 @@ ipcMain.handle('browser:clear-data', async () => {
 
 // Hand the user's own logged-in cookies for a vetted social platform to its session-backed MCP shim (Reddit/X/TikTok). Reads from the browser partition's main-process cookie store, so httpOnly auth cookies (e.g. reddit_session) are included, which document.cookie can't see. Allowlisted domains ONLY, so this can never become a general cookie-theft surface; the backend re-checks the same allowlist before it ever calls this.
 const SESSION_COOKIE_DOMAINS = ['reddit.com', 'x.com', 'twitter.com', 'tiktok.com'];
-ipcMain.handle('get-partition-cookies', async (_e, domain) => {
+async function readPartitionCookies(domain) {
   const d = String(domain || '').toLowerCase().trim().replace(/^\./, '');
   if (!SESSION_COOKIE_DOMAINS.includes(d)) {
     return { cookies: [], userAgent: '', error: `domain not allowed: ${d || '(empty)'}` };
@@ -2795,7 +2796,38 @@ ipcMain.handle('get-partition-cookies', async (_e, domain) => {
   } catch (err) {
     return { cookies: [], userAgent: '', error: `cookie read failed: ${err && err.message}` };
   }
-});
+}
+ipcMain.handle('get-partition-cookies', (_e, domain) => readPartitionCookies(domain));
+
+// The renderer relays cookie reads for the session-borrow bridge, but macOS throttles it when the
+// window is backgrounded, so those reads intermittently time out. Main never throttles: hold our own
+// socket to the backend and answer get_session_cookies here. Cookie reads only; the renderer still
+// owns everything that needs a live webview (navigate/click/perform_action).
+let p_mainBridgeWs = null;
+let p_mainBridgeStopped = false;
+function connectMainBridge() {
+  if (p_mainBridgeStopped || !backendPort || !authToken || p_mainBridgeWs) return;
+  let ws;
+  try {
+    ws = new WebSocket(`ws://127.0.0.1:${backendPort}/ws/electron-main?token=${encodeURIComponent(authToken)}`);
+  } catch (_) {
+    setTimeout(connectMainBridge, 3000);
+    return;
+  }
+  p_mainBridgeWs = ws;
+  ws.addEventListener('message', async (ev) => {
+    let msg;
+    try { msg = JSON.parse(typeof ev.data === 'string' ? ev.data : ''); } catch (_) { return; }
+    if (!msg || msg.event !== 'browser:command') return;
+    const cmd = msg.data || {};
+    if (cmd.action !== 'get_session_cookies') return;
+    const result = await readPartitionCookies((cmd.params && cmd.params.domain) || '');
+    try { ws.send(JSON.stringify({ event: 'browser:result', data: { request_id: cmd.request_id, ...result } })); } catch (_) {}
+  });
+  const retry = () => { p_mainBridgeWs = null; if (!p_mainBridgeStopped) setTimeout(connectMainBridge, 3000); };
+  ws.addEventListener('close', retry);
+  ws.addEventListener('error', () => { try { ws.close(); } catch (_) { retry(); } });
+}
 
 ipcMain.handle('get-update-status', () => cachedUpdateStatus);
 
diff --git a/linter/config/config.json b/linter/config/config.json
index 20ae95f8..f3d7a864 100644
--- a/linter/config/config.json
+++ b/linter/config/config.json
@@ -68,6 +68,7 @@
       "backend/apps/agents/browser/browser_agent.py",
       "backend/apps/agents/browser_agent_mcp_server.py",
       "backend/apps/agents/browser/browser_schema.py",
+      "backend/apps/agents/core/ws_manager.py",
       "backend/apps/agents/manager/prompt/prompt_context.py",
       "backend/apps/agents/manager/prompt/attachments.py",
       "backend/apps/agents/providers/pricing.py",