diff --git a/apps/ade-cli/src/tuiClient/__tests__/multiChatLayout.test.ts b/apps/ade-cli/src/tuiClient/__tests__/multiChatLayout.test.ts
index 18be57639..132d66600 100644
--- a/apps/ade-cli/src/tuiClient/__tests__/multiChatLayout.test.ts
+++ b/apps/ade-cli/src/tuiClient/__tests__/multiChatLayout.test.ts
@@ -1,5 +1,44 @@
 import { describe, expect, it } from "vitest";
-import { canRenderMultiChatGrid, computeTileRects, focusedSessionIdForMultiView } from "../multiChatLayout";
+import {
+  canRenderMultiChatGrid,
+  computeTileRects,
+  focusedSessionIdForMultiView,
+  resolveOpenChatSessionIds,
+} from "../multiChatLayout";
+
+describe("resolveOpenChatSessionIds", () => {
+  const multiView = {
+    tiles: [
+      { sessionId: "tile-a", laneId: "lane-1" },
+      { sessionId: "tile-b", laneId: "lane-1" },
+    ],
+    focusedIndex: 0,
+  };
+
+  it("streams tile sessions when the grid is visible", () => {
+    expect(resolveOpenChatSessionIds({
+      gridViewActive: true,
+      multiView,
+      activeSessionId: "other-chat",
+    })).toEqual(new Set(["tile-a", "tile-b"]));
+  });
+
+  it("streams only the active chat when a resumable grid is hidden", () => {
+    expect(resolveOpenChatSessionIds({
+      gridViewActive: false,
+      multiView,
+      activeSessionId: "solo-chat",
+    })).toEqual(new Set(["solo-chat"]));
+  });
+
+  it("streams the active chat when no grid exists", () => {
+    expect(resolveOpenChatSessionIds({
+      gridViewActive: false,
+      multiView: null,
+      activeSessionId: "solo-chat",
+    })).toEqual(new Set(["solo-chat"]));
+  });
+});
 
 describe("multi chat layout", () => {
   it("computes the locked 1-6 tile patterns inside the available area", () => {
diff --git a/apps/ade-cli/src/tuiClient/app.tsx b/apps/ade-cli/src/tuiClient/app.tsx
index 9efb90e99..d0a4b3b66 100644
--- a/apps/ade-cli/src/tuiClient/app.tsx
+++ b/apps/ade-cli/src/tuiClient/app.tsx
@@ -183,6 +183,7 @@ import {
 } from "./hitTestRegistry";
 import {
   focusedSessionIdForMultiView,
+  resolveOpenChatSessionIds,
   type MultiViewState,
   type MultiViewTile,
 } from "./multiChatLayout";
@@ -5870,12 +5871,11 @@ export function AdeCodeApp({ project, forceEmbedded, requireSocket, socketPath }
   useEffect(() => {
     if (!connection) return;
     const unsubscribe = connection.onChatEvent((envelope) => {
-      const currentMultiView = multiViewRef.current;
-      const openSessionIds = new Set(
-        currentMultiView
-          ? currentMultiView.tiles.map((tile) => tile.sessionId)
-          : [activeSessionIdRef.current].filter((value): value is string => Boolean(value)),
-      );
+      const openSessionIds = resolveOpenChatSessionIds({
+        gridViewActive: gridViewActiveRef.current,
+        multiView: multiViewRef.current,
+        activeSessionId: activeSessionIdRef.current,
+      });
       if (!openSessionIds.has(envelope.sessionId)) {
         // Event for a session we're not displaying — refresh summaries (cheap,
         // dedup-guarded). Only the open-session token stream below is coalesced.
diff --git a/apps/ade-cli/src/tuiClient/multiChatLayout.ts b/apps/ade-cli/src/tuiClient/multiChatLayout.ts
index bbc775db8..9762120af 100644
--- a/apps/ade-cli/src/tuiClient/multiChatLayout.ts
+++ b/apps/ade-cli/src/tuiClient/multiChatLayout.ts
@@ -88,3 +88,15 @@ export function focusedSessionIdForMultiView(multiView: MultiViewState | null):
   if (!multiView) return null;
   return multiView.tiles[multiView.focusedIndex]?.sessionId ?? null;
 }
+
+/** Session ids that should receive live chat event streaming (not summary-only refresh). */
+export function resolveOpenChatSessionIds(args: {
+  gridViewActive: boolean;
+  multiView: MultiViewState | null;
+  activeSessionId: string | null;
+}): Set<string> {
+  if (args.gridViewActive && args.multiView) {
+    return new Set(args.multiView.tiles.map((tile) => tile.sessionId));
+  }
+  return args.activeSessionId ? new Set([args.activeSessionId]) : new Set();
+}