Preserve provider changes before sending

web/src/App.tsx

@@ -63,6 +63,10 @@ import {
   type WorkspaceItem,
 } from "@/lib/api";
 import { useSessionAuth } from "@/hooks/use-session-auth";
+import {
+  getChatModelSelection,
+  getChatModelSelectionSyncKey,
+} from "@/lib/chat-model-selection";
 import {
   resolveSidebarSelectionAfterRefresh,
   type SidebarSelection,
@@ -545,14 +549,6 @@ function normalizeEnabledTools(value: unknown, availableTools: ChatToolInfo[]) {
   );
 }
 
-function getChatModelSelection(chat: Pick<ChatSummary, "lastUsedProvider" | "lastUsedModel"> | Pick<ChatDetail, "lastUsedProvider" | "lastUsedModel"> | null) {
-  if (!chat?.lastUsedProvider || !chat.lastUsedModel?.trim()) return null;
-  return {
-    provider: chat.lastUsedProvider,
-    model: chat.lastUsedModel.trim(),
-  };
-}
-
 type ToolLogMetadata = {
   kind: "tool_call";
   toolCallId?: string;
@@ -1562,15 +1558,32 @@ export default function App() {
     return searches.find((search) => search.id === selectedItem.id) ?? null;
   }, [searches, selectedItem]);
 
-  useEffect(() => {
-    if (draftKind || selectedItem?.kind !== "chat") return;
+  const selectedChatModelSelection = useMemo(() => {
+    if (draftKind || selectedItem?.kind !== "chat") return null;
     const detailSelection = selectedChat?.id === selectedItem.id ? getChatModelSelection(selectedChat) : null;
     const summarySelection = getChatModelSelection(selectedChatSummary);
-    const nextSelection = detailSelection ?? summarySelection;
-    if (!nextSelection) return;
-    setProvider(nextSelection.provider);
-    setModel(nextSelection.model);
-  }, [draftKind, selectedChat, selectedChatSummary, selectedItem]);
+    return detailSelection ?? summarySelection;
+  }, [
+    draftKind,
+    selectedChat?.id,
+    selectedChat?.lastUsedModel,
+    selectedChat?.lastUsedProvider,
+    selectedChatSummary?.id,
+    selectedChatSummary?.lastUsedModel,
+    selectedChatSummary?.lastUsedProvider,
+    selectedItem?.id,
+    selectedItem?.kind,
+  ]);
+  const selectedChatModelSelectionSyncKey = getChatModelSelectionSyncKey(
+    selectedItem?.kind === "chat" ? selectedItem.id : null,
+    selectedChatModelSelection
+  );
+
+  useEffect(() => {
+    if (!selectedChatModelSelection) return;
+    setProvider(selectedChatModelSelection.provider);
+    setModel(selectedChatModelSelection.model);
+  }, [selectedChatModelSelectionSyncKey]);
 
   useEffect(() => {
     if (draftKind === "chat") return;