Support concurrent chats (#1478)

Fixes #212 


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Add concurrent chat support with per-chat state, chat activity UI, IPC
per-chat handling, and accompanying tests.
> 
> - **Frontend (Chat concurrency)**
> - Replace global chat atoms with per-chat maps:
`chatMessagesByIdAtom`, `isStreamingByIdAtom`, `chatErrorByIdAtom`,
`chatStreamCountByIdAtom`, `recentStreamChatIdsAtom`.
> - Update `ChatPanel`, `ChatInput`, `MessagesList`,
`DyadMarkdownParser`, and `useVersions` to read/write per-chat state.
> - Add `useSelectChat` to centralize selecting/navigating chats; wire
into `ChatList`.
> - **UI**
> - Add chat activity popover: `ChatActivityButton` and list; integrate
into `preview_panel/ActionHeader` (renamed from `PreviewHeader`) and
swap in `TitleBar`.
> - **IPC/Main**
> - Send error payloads with `chatId` on `chat:response:error`; update
`ipc_client` to route errors per chat.
> - Persist streaming partial assistant content periodically; improve
cancellation/end handling.
> - Make `FileUploadsState` per-chat (`addFileUpload({chatId,fileId},
...)`, `clear(chatId)`, `getFileUploadsForChat(chatId)`); update
handlers/processors accordingly.
> - **Testing**
> - Add e2e `concurrent_chat.spec.ts` and snapshots; extend helpers
(`snapshotMessages` timeout, chat activity helpers).
> - Fake LLM server: support `tc=` with options, optional sleep delay to
simulate concurrency.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
9035f30b73a1f2e5a366a0cac1c63411742b16f3. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

e2e-tests/concurrent_chat.spec.ts

@@ -0,0 +1,25 @@
+import { test } from "./helpers/test_helper";
+import { expect } from "@playwright/test";
+
+test("concurrent chat", async ({ po }) => {
+  await po.setUp();
+  await po.sendPrompt("tc=chat1 [sleep=medium]", {
+    skipWaitForCompletion: true,
+  });
+  // Need a short wait otherwise the click on Apps tab is ignored.
+  await po.sleep(2_000);
+
+  await po.goToAppsTab();
+  await po.sendPrompt("tc=chat2");
+  await po.snapshotMessages();
+  await po.clickChatActivityButton();
+
+  // Chat #1 will be the last in the list
+  expect(
+    await po.page.getByTestId(`chat-activity-list-item-1`).textContent(),
+  ).toContain("Chat #1");
+  await po.page.getByTestId(`chat-activity-list-item-1`).click();
+  await po.snapshotMessages({ timeout: 12_000 });
+
+  //
+});

e2e-tests/helpers/test_helper.ts

@@ -400,7 +400,8 @@ export class PageObject {
 
   async snapshotMessages({
     replaceDumpPath = false,
-  }: { replaceDumpPath?: boolean } = {}) {
+    timeout,
+  }: { replaceDumpPath?: boolean; timeout?: number } = {}) {
     if (replaceDumpPath) {
       // Update page so that "[[dyad-dump-path=*]]" is replaced with a placeholder path
       // which is stable across runs.
@@ -417,7 +418,9 @@ export class PageObject {
         );
       });
     }
-    await expect(this.page.getByTestId("messages-list")).toMatchAriaSnapshot();
+    await expect(this.page.getByTestId("messages-list")).toMatchAriaSnapshot({
+      timeout,
+    });
   }
 
   async approveProposal() {
@@ -461,6 +464,16 @@ export class PageObject {
     await this.page.getByTestId(`${mode}-mode-button`).click();
   }
 
+  async clickChatActivityButton() {
+    await this.page.getByTestId("chat-activity-button").click();
+  }
+
+  async snapshotChatActivityList() {
+    await expect(
+      this.page.getByTestId("chat-activity-list"),
+    ).toMatchAriaSnapshot();
+  }
+
   async clickRecheckProblems() {
     await this.page.getByTestId("recheck-button").click();
   }

e2e-tests/snapshots/concurrent_chat.spec.ts_concurrent-chat-1.aria.yml

@@ -0,0 +1,8 @@
+- paragraph: tc=chat2
+- paragraph: chat2
+- button:
+  - img
+- img
+- text: less than a minute ago
+- button "Retry":
+  - img

e2e-tests/snapshots/concurrent_chat.spec.ts_concurrent-chat-2.aria.yml

@@ -0,0 +1,8 @@
+- paragraph: tc=chat1 [sleep=medium]
+- paragraph: chat1
+- button:
+  - img
+- img
+- text: less than a minute ago
+- button "Retry":
+  - img

src/app/TitleBar.tsx

@@ -20,7 +20,7 @@ import {
   TooltipContent,
   TooltipTrigger,
 } from "@/components/ui/tooltip";
-import { PreviewHeader } from "@/components/preview_panel/PreviewHeader";
+import { ActionHeader } from "@/components/preview_panel/ActionHeader";
 
 export const TitleBar = () => {
   const [selectedAppId] = useAtom(selectedAppIdAtom);
@@ -97,7 +97,7 @@ export const TitleBar = () => {
         {/* Preview Header */}
         {location.pathname === "/chat" && (
           <div className="flex-1 flex justify-end">
-            <PreviewHeader />
+            <ActionHeader />
           </div>
         )}
 

src/atoms/chatAtoms.ts

@@ -2,14 +2,14 @@ import type { Message } from "@/ipc/ipc_types";
 import { atom } from "jotai";
 import type { ChatSummary } from "@/lib/schemas";
 
-// Atom to hold the chat history
+// Per-chat atoms implemented with maps keyed by chatId
-export const chatMessagesAtom = atom<Message[]>([]);
+export const chatMessagesByIdAtom = atom<Map<number, Message[]>>(new Map());
-export const chatErrorAtom = atom<string | null>(null);
+export const chatErrorByIdAtom = atom<Map<number, string | null>>(new Map());
 
 // Atom to hold the currently selected chat ID
 export const selectedChatIdAtom = atom<number | null>(null);
 
-export const isStreamingAtom = atom<boolean>(false);
+export const isStreamingByIdAtom = atom<Map<number, boolean>>(new Map());
 export const chatInputValueAtom = atom<string>("");
 export const homeChatInputValueAtom = atom<string>("");
 
@@ -17,5 +17,6 @@ export const homeChatInputValueAtom = atom<string>("");
 export const chatsAtom = atom<ChatSummary[]>([]);
 export const chatsLoadingAtom = atom<boolean>(false);
 
-// Used for scrolling to the bottom of the chat messages
+// Used for scrolling to the bottom of the chat messages (per chat)
-export const chatStreamCountAtom = atom<number>(0);
+export const chatStreamCountByIdAtom = atom<Map<number, number>>(new Map());
+export const recentStreamChatIdsAtom = atom<Set<number>>(new Set<number>());

src/components/ChatList.tsx

@@ -28,11 +28,12 @@ import { RenameChatDialog } from "@/components/chat/RenameChatDialog";
 import { DeleteChatDialog } from "@/components/chat/DeleteChatDialog";
 
 import { ChatSearchDialog } from "./ChatSearchDialog";
+import { useSelectChat } from "@/hooks/useSelectChat";
 
 export function ChatList({ show }: { show?: boolean }) {
   const navigate = useNavigate();
   const [selectedChatId, setSelectedChatId] = useAtom(selectedChatIdAtom);
-  const [selectedAppId, setSelectedAppId] = useAtom(selectedAppIdAtom);
+  const [selectedAppId] = useAtom(selectedAppIdAtom);
   const [, setIsDropdownOpen] = useAtom(dropdownOpenAtom);
 
   const { chats, loading, refreshChats } = useChats(selectedAppId);
@@ -51,6 +52,7 @@ export function ChatList({ show }: { show?: boolean }) {
 
   // search dialog state
   const [isSearchDialogOpen, setIsSearchDialogOpen] = useState(false);
+  const { selectChat } = useSelectChat();
 
   // Update selectedChatId when route changes
   useEffect(() => {
@@ -74,13 +76,8 @@ export function ChatList({ show }: { show?: boolean }) {
     chatId: number;
     appId: number;
   }) => {
-    setSelectedChatId(chatId);
+    selectChat({ chatId, appId });
-    setSelectedAppId(appId);
     setIsSearchDialogOpen(false);
-    navigate({
-      to: "/chat",
-      search: { id: chatId },
-    });
   };
 
   const handleNewChat = async () => {

src/components/ChatPanel.tsx

@@ -1,6 +1,9 @@
 import { useState, useRef, useEffect, useCallback } from "react";
-import { useAtom, useAtomValue } from "jotai";
+import { useAtomValue, useSetAtom } from "jotai";
-import { chatMessagesAtom, chatStreamCountAtom } from "../atoms/chatAtoms";
+import {
+  chatMessagesByIdAtom,
+  chatStreamCountByIdAtom,
+} from "../atoms/chatAtoms";
 import { IpcClient } from "@/ipc/ipc_client";
 
 import { ChatHeader } from "./chat/ChatHeader";
@@ -20,10 +23,11 @@ export function ChatPanel({
   isPreviewOpen,
   onTogglePreview,
 }: ChatPanelProps) {
-  const [messages, setMessages] = useAtom(chatMessagesAtom);
+  const messagesById = useAtomValue(chatMessagesByIdAtom);
+  const setMessagesById = useSetAtom(chatMessagesByIdAtom);
   const [isVersionPaneOpen, setIsVersionPaneOpen] = useState(false);
   const [error, setError] = useState<string | null>(null);
-  const streamCount = useAtomValue(chatStreamCountAtom);
+  const streamCountById = useAtomValue(chatStreamCountByIdAtom);
   // Reference to store the processed prompt so we don't submit it twice
 
   const messagesEndRef = useRef<HTMLDivElement | null>(null);
@@ -60,9 +64,10 @@ export function ChatPanel({
   };
 
   useEffect(() => {
+    const streamCount = chatId ? (streamCountById.get(chatId) ?? 0) : 0;
     console.log("streamCount", streamCount);
     scrollToBottom();
-  }, [streamCount]);
+  }, [chatId, chatId ? (streamCountById.get(chatId) ?? 0) : 0]);
 
   useEffect(() => {
     const container = messagesContainerRef.current;
@@ -82,17 +87,22 @@ export function ChatPanel({
 
   const fetchChatMessages = useCallback(async () => {
     if (!chatId) {
-      setMessages([]);
+      // no-op when no chat
       return;
     }
     const chat = await IpcClient.getInstance().getChat(chatId);
-    setMessages(chat.messages);
+    setMessagesById((prev) => {
-  }, [chatId, setMessages]);
+      const next = new Map(prev);
+      next.set(chatId, chat.messages);
+      return next;
+    });
+  }, [chatId, setMessagesById]);
 
   useEffect(() => {
     fetchChatMessages();
   }, [fetchChatMessages]);
 
+  const messages = chatId ? (messagesById.get(chatId) ?? []) : [];
   // Auto-scroll effect when messages change
   useEffect(() => {
     if (

src/components/chat/ChatActivity.tsx

@@ -0,0 +1,145 @@
+import { useEffect, useMemo, useState } from "react";
+
+import { Bell, Loader2, CheckCircle2 } from "lucide-react";
+import {
+  Popover,
+  PopoverContent,
+  PopoverTrigger,
+} from "@/components/ui/popover";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+import { getAllChats } from "@/lib/chat";
+import type { ChatSummary } from "@/lib/schemas";
+import { useAtomValue } from "jotai";
+import {
+  isStreamingByIdAtom,
+  recentStreamChatIdsAtom,
+} from "@/atoms/chatAtoms";
+import { useLoadApps } from "@/hooks/useLoadApps";
+import { useSelectChat } from "@/hooks/useSelectChat";
+
+export function ChatActivityButton() {
+  const [open, setOpen] = useState(false);
+  const isStreamingById = useAtomValue(isStreamingByIdAtom);
+  const isAnyStreaming = useMemo(() => {
+    for (const v of isStreamingById.values()) {
+      if (v) return true;
+    }
+    return false;
+  }, [isStreamingById]);
+  return (
+    <Popover open={open} onOpenChange={setOpen}>
+      <Tooltip>
+        <TooltipTrigger asChild>
+          <PopoverTrigger asChild>
+            <button
+              className="no-app-region-drag relative flex items-center justify-center p-1.5 rounded-md text-sm hover:bg-[var(--background-darkest)] transition-colors"
+              data-testid="chat-activity-button"
+            >
+              {isAnyStreaming && (
+                <span className="pointer-events-none absolute inset-0 flex items-center justify-center">
+                  <span className="block size-7 rounded-full border-3 border-blue-500/60 border-t-transparent animate-spin" />
+                </span>
+              )}
+              <Bell size={16} />
+            </button>
+          </PopoverTrigger>
+        </TooltipTrigger>
+        <TooltipContent>Recent chat activity</TooltipContent>
+      </Tooltip>
+      <PopoverContent
+        align="end"
+        className="w-80 p-0 max-h-[50vh] overflow-y-auto"
+      >
+        <ChatActivityList onSelect={() => setOpen(false)} />
+      </PopoverContent>
+    </Popover>
+  );
+}
+
+function ChatActivityList({ onSelect }: { onSelect?: () => void }) {
+  const [chats, setChats] = useState<ChatSummary[]>([]);
+  const [loading, setLoading] = useState(true);
+  const isStreamingById = useAtomValue(isStreamingByIdAtom);
+  const recentStreamChatIds = useAtomValue(recentStreamChatIdsAtom);
+  const apps = useLoadApps();
+  const { selectChat } = useSelectChat();
+  useEffect(() => {
+    let mounted = true;
+    (async () => {
+      try {
+        const all = await getAllChats();
+        if (!mounted) return;
+        const recent = Array.from(recentStreamChatIds)
+          .map((id) => all.find((c) => c.id === id))
+          .filter((c) => c !== undefined);
+        // Sort recent first
+        setChats([...recent].reverse());
+      } finally {
+        if (mounted) setLoading(false);
+      }
+    })();
+    return () => {
+      mounted = false;
+    };
+  }, [recentStreamChatIds]);
+
+  const rows = useMemo(() => chats.slice(0, 30), [chats]);
+
+  if (loading) {
+    return (
+      <div className="p-4 text-sm text-muted-foreground flex items-center gap-2">
+        <Loader2 size={16} className="animate-spin" />
+        Loading activity…
+      </div>
+    );
+  }
+
+  if (rows.length === 0) {
+    return (
+      <div className="p-4 text-sm text-muted-foreground">No recent chats</div>
+    );
+  }
+
+  return (
+    <div className="py-1" data-testid="chat-activity-list">
+      {rows.map((c) => {
+        const inProgress = isStreamingById.get(c.id) === true;
+        return (
+          <button
+            key={c.id}
+            className="w-full text-left px-3 py-2 flex items-center justify-between gap-2 rounded-md hover:bg-[var(--background-darker)] dark:hover:bg-[var(--background-lighter)] transition-colors"
+            onClick={() => {
+              onSelect?.();
+              selectChat({ chatId: c.id, appId: c.appId });
+            }}
+            data-testid={`chat-activity-list-item-${c.id}`}
+          >
+            <div className="min-w-0">
+              <div className="truncate text-sm font-medium">
+                {c.title ?? `Chat #${c.id}`}
+              </div>
+              <div className="text-xs text-muted-foreground">
+                {apps.apps.find((a) => a.id === c.appId)?.name}
+              </div>
+            </div>
+            <div className="flex items-center gap-2">
+              {inProgress ? (
+                <div className="flex items-center text-purple-600">
+                  <Loader2 size={16} className="animate-spin" />
+                </div>
+              ) : (
+                <div className="flex items-center text-emerald-600">
+                  <CheckCircle2 size={16} />
+                </div>
+              )}
+            </div>
+          </button>
+        );
+      })}
+    </div>
+  );
+}

src/components/chat/ChatInput.tsx

@@ -24,7 +24,7 @@ import { useSettings } from "@/hooks/useSettings";
 import { IpcClient } from "@/ipc/ipc_client";
 import {
   chatInputValueAtom,
-  chatMessagesAtom,
+  chatMessagesByIdAtom,
   selectedChatIdAtom,
 } from "@/atoms/chatAtoms";
 import { atom, useAtom, useSetAtom, useAtomValue } from "jotai";
@@ -39,7 +39,7 @@ import {
   FileChange,
   SqlQuery,
 } from "@/lib/schemas";
-import type { Message } from "@/ipc/ipc_types";
+
 import { isPreviewOpenAtom } from "@/atoms/viewAtoms";
 import { useRunApp } from "@/hooks/useRunApp";
 import { AutoApproveSwitch } from "../AutoApproveSwitch";
@@ -80,7 +80,8 @@ export function ChatInput({ chatId }: { chatId?: number }) {
   const [showError, setShowError] = useState(true);
   const [isApproving, setIsApproving] = useState(false); // State for approving
   const [isRejecting, setIsRejecting] = useState(false); // State for rejecting
-  const [messages, setMessages] = useAtom<Message[]>(chatMessagesAtom);
+  const messagesById = useAtomValue(chatMessagesByIdAtom);
+  const setMessagesById = useSetAtom(chatMessagesByIdAtom);
   const setIsPreviewOpen = useSetAtom(isPreviewOpenAtom);
   const [showTokenBar, setShowTokenBar] = useAtom(showTokenBarAtom);
   const [selectedComponent, setSelectedComponent] = useAtom(
@@ -110,7 +111,7 @@ export function ChatInput({ chatId }: { chatId?: number }) {
   const { proposal, messageId } = proposalResult ?? {};
   useChatModeToggle();
 
-  const lastMessage = messages.at(-1);
+  const lastMessage = (chatId ? (messagesById.get(chatId) ?? []) : []).at(-1);
   const disableSendButton =
     lastMessage?.role === "assistant" &&
     !lastMessage.approvalState &&
@@ -126,12 +127,15 @@ export function ChatInput({ chatId }: { chatId?: number }) {
 
   const fetchChatMessages = useCallback(async () => {
     if (!chatId) {
-      setMessages([]);
       return;
     }
     const chat = await IpcClient.getInstance().getChat(chatId);
-    setMessages(chat.messages);
+    setMessagesById((prev) => {
-  }, [chatId, setMessages]);
+      const next = new Map(prev);
+      next.set(chatId, chat.messages);
+      return next;
+    });
+  }, [chatId, setMessagesById]);
 
   const handleSubmit = async () => {
     if (

src/components/chat/DyadMarkdownParser.tsx

@@ -12,7 +12,7 @@ import { DyadCodebaseContext } from "./DyadCodebaseContext";
 import { DyadThink } from "./DyadThink";
 import { CodeHighlight } from "./CodeHighlight";
 import { useAtomValue } from "jotai";
-import { isStreamingAtom } from "@/atoms/chatAtoms";
+import { isStreamingByIdAtom, selectedChatIdAtom } from "@/atoms/chatAtoms";
 import { CustomTagState } from "./stateTypes";
 import { DyadOutput } from "./DyadOutput";
 import { DyadProblemSummary } from "./DyadProblemSummary";
@@ -79,7 +79,8 @@ export const VanillaMarkdownParser = ({ content }: { content: string }) => {
 export const DyadMarkdownParser: React.FC<DyadMarkdownParserProps> = ({
   content,
 }) => {
-  const isStreaming = useAtomValue(isStreamingAtom);
+  const chatId = useAtomValue(selectedChatIdAtom);
+  const isStreaming = useAtomValue(isStreamingByIdAtom).get(chatId!) ?? false;
   // Extract content pieces (markdown and custom tags)
   const contentPieces = useMemo(() => {
     return parseCustomTags(content);

src/components/chat/MessagesList.tsx

@@ -13,7 +13,7 @@ import { useVersions } from "@/hooks/useVersions";
 import { selectedAppIdAtom } from "@/atoms/appAtoms";
 import { showError, showWarning } from "@/lib/toast";
 import { IpcClient } from "@/ipc/ipc_client";
-import { chatMessagesAtom } from "@/atoms/chatAtoms";
+import { chatMessagesByIdAtom } from "@/atoms/chatAtoms";
 import { useLanguageModelProviders } from "@/hooks/useLanguageModelProviders";
 import { useSettings } from "@/hooks/useSettings";
 import { useUserBudgetInfo } from "@/hooks/useUserBudgetInfo";
@@ -31,7 +31,7 @@ export const MessagesList = forwardRef<HTMLDivElement, MessagesListProps>(
     const { streamMessage, isStreaming } = useStreamChat();
     const { isAnyProviderSetup, isProviderSetup } = useLanguageModelProviders();
     const { settings } = useSettings();
-    const setMessages = useSetAtom(chatMessagesAtom);
+    const setMessagesById = useSetAtom(chatMessagesByIdAtom);
     const [isUndoLoading, setIsUndoLoading] = useState(false);
     const [isRetryLoading, setIsRetryLoading] = useState(false);
     const selectedChatId = useAtomValue(selectedChatIdAtom);
@@ -107,7 +107,11 @@ export const MessagesList = forwardRef<HTMLDivElement, MessagesListProps>(
                             await IpcClient.getInstance().getChat(
                               selectedChatId,
                             );
-                          setMessages(chat.messages);
+                          setMessagesById((prev) => {
+                            const next = new Map(prev);
+                            next.set(selectedChatId, chat.messages);
+                            return next;
+                          });
                         }
                       } else {
                         const chat =
@@ -120,7 +124,11 @@ export const MessagesList = forwardRef<HTMLDivElement, MessagesListProps>(
                             await IpcClient.getInstance().deleteMessages(
                               selectedChatId,
                             );
-                            setMessages([]);
+                            setMessagesById((prev) => {
+                              const next = new Map(prev);
+                              next.set(selectedChatId, []);
+                              return next;
+                            });
                           } catch (err) {
                             showError(err);
                           }

src/components/preview_panel/ActionHeader.tsx

@@ -12,6 +12,7 @@ import {
   Wrench,
   Globe,
 } from "lucide-react";
+import { ChatActivityButton } from "@/components/chat/ChatActivity";
 import { motion } from "framer-motion";
 import { useEffect, useRef, useState, useCallback } from "react";
 
@@ -44,7 +45,7 @@ const BUTTON_CLASS_NAME =
   "no-app-region-drag cursor-pointer relative flex items-center gap-1 px-2 py-1 rounded-md text-[13px] font-medium z-10 hover:bg-[var(--background)]";
 
 // Preview Header component with preview mode toggle
-export const PreviewHeader = () => {
+export const ActionHeader = () => {
   const [previewMode, setPreviewMode] = useAtom(previewModeAtom);
   const [isPreviewOpen, setIsPreviewOpen] = useAtom(isPreviewOpenAtom);
   const selectedAppId = useAtomValue(selectedAppIdAtom);
@@ -58,7 +59,7 @@ export const PreviewHeader = () => {
   const { problemReport } = useCheckProblems(selectedAppId);
   const { restartApp, refreshAppIframe } = useRunApp();
 
-  const isCompact = windowWidth < 860;
+  const isCompact = windowWidth < 888;
 
   // Track window width
   useEffect(() => {
@@ -257,7 +258,9 @@ export const PreviewHeader = () => {
             "publish-mode-button",
           )}
         </div>
-        <div className="flex items-center">
+        {/* Chat activity bell */}
+        <div className="flex items-center gap-1">
+          <ChatActivityButton />
           <DropdownMenu>
             <DropdownMenuTrigger asChild>
               <button

src/hooks/useSelectChat.ts

@@ -0,0 +1,21 @@
+import { useSetAtom } from "jotai";
+import { selectedChatIdAtom } from "@/atoms/chatAtoms";
+import { selectedAppIdAtom } from "@/atoms/appAtoms";
+import { useNavigate } from "@tanstack/react-router";
+
+export function useSelectChat() {
+  const setSelectedChatId = useSetAtom(selectedChatIdAtom);
+  const setSelectedAppId = useSetAtom(selectedAppIdAtom);
+  const navigate = useNavigate();
+
+  return {
+    selectChat: ({ chatId, appId }: { chatId: number; appId: number }) => {
+      setSelectedChatId(chatId);
+      setSelectedAppId(appId);
+      navigate({
+        to: "/chat",
+        search: { id: chatId },
+      });
+    },
+  };
+}

src/hooks/useStreamChat.ts

@@ -4,12 +4,13 @@ import type {
   Message,
   FileAttachment,
 } from "@/ipc/ipc_types";
-import { useAtom, useSetAtom } from "jotai";
+import { useAtom, useAtomValue, useSetAtom } from "jotai";
 import {
-  chatErrorAtom,
+  chatErrorByIdAtom,
-  chatMessagesAtom,
+  chatMessagesByIdAtom,
-  chatStreamCountAtom,
+  chatStreamCountByIdAtom,
-  isStreamingAtom,
+  isStreamingByIdAtom,
+  recentStreamChatIdsAtom,
 } from "@/atoms/chatAtoms";
 import { IpcClient } from "@/ipc/ipc_client";
 import { isPreviewOpenAtom } from "@/atoms/viewAtoms";
@@ -35,20 +36,24 @@ export function getRandomNumberId() {
 export function useStreamChat({
   hasChatId = true,
 }: { hasChatId?: boolean } = {}) {
-  const [, setMessages] = useAtom(chatMessagesAtom);
+  const setMessagesById = useSetAtom(chatMessagesByIdAtom);
-  const [isStreaming, setIsStreaming] = useAtom(isStreamingAtom);
+  const isStreamingById = useAtomValue(isStreamingByIdAtom);
-  const [error, setError] = useAtom(chatErrorAtom);
+  const setIsStreamingById = useSetAtom(isStreamingByIdAtom);
+  const errorById = useAtomValue(chatErrorByIdAtom);
+  const setErrorById = useSetAtom(chatErrorByIdAtom);
   const setIsPreviewOpen = useSetAtom(isPreviewOpenAtom);
   const [selectedAppId] = useAtom(selectedAppIdAtom);
   const { refreshChats } = useChats(selectedAppId);
   const { refreshApp } = useLoadApp(selectedAppId);
-  const setStreamCount = useSetAtom(chatStreamCountAtom);
+
+  const setStreamCountById = useSetAtom(chatStreamCountByIdAtom);
   const { refreshVersions } = useVersions(selectedAppId);
   const { refreshAppIframe } = useRunApp();
   const { countTokens } = useCountTokens();
   const { refetchUserBudget } = useUserBudgetInfo();
   const { checkProblems } = useCheckProblems(selectedAppId);
   const { settings } = useSettings();
+  const setRecentStreamChatIds = useSetAtom(recentStreamChatIdsAtom);
   const posthog = usePostHog();
   let chatId: number | undefined;
 
@@ -79,8 +84,22 @@ export function useStreamChat({
         return;
       }
 
-      setError(null);
+      setRecentStreamChatIds((prev) => {
-      setIsStreaming(true);
+        const next = new Set(prev);
+        next.add(chatId);
+        return next;
+      });
+
+      setErrorById((prev) => {
+        const next = new Map(prev);
+        next.set(chatId, null);
+        return next;
+      });
+      setIsStreamingById((prev) => {
+        const next = new Map(prev);
+        next.set(chatId, true);
+        return next;
+      });
 
       let hasIncrementedStreamCount = false;
       try {
@@ -91,11 +110,19 @@ export function useStreamChat({
           attachments,
           onUpdate: (updatedMessages: Message[]) => {
             if (!hasIncrementedStreamCount) {
-              setStreamCount((streamCount) => streamCount + 1);
+              setStreamCountById((prev) => {
+                const next = new Map(prev);
+                next.set(chatId, (prev.get(chatId) ?? 0) + 1);
+                return next;
+              });
               hasIncrementedStreamCount = true;
             }
 
-            setMessages(updatedMessages);
+            setMessagesById((prev) => {
+              const next = new Map(prev);
+              next.set(chatId, updatedMessages);
+              return next;
+            });
           },
           onEnd: (response: ChatResponseEnd) => {
             if (response.updatedFiles) {
@@ -117,7 +144,11 @@ export function useStreamChat({
             refetchUserBudget();
 
             // Keep the same as below
-            setIsStreaming(false);
+            setIsStreamingById((prev) => {
+              const next = new Map(prev);
+              next.set(chatId, false);
+              return next;
+            });
             refreshChats();
             refreshApp();
             refreshVersions();
@@ -125,10 +156,18 @@ export function useStreamChat({
           },
           onError: (errorMessage: string) => {
             console.error(`[CHAT] Stream error for ${chatId}:`, errorMessage);
-            setError(errorMessage);
+            setErrorById((prev) => {
+              const next = new Map(prev);
+              next.set(chatId, errorMessage);
+              return next;
+            });
 
             // Keep the same as above
-            setIsStreaming(false);
+            setIsStreamingById((prev) => {
+              const next = new Map(prev);
+              next.set(chatId, false);
+              return next;
+            });
             refreshChats();
             refreshApp();
             refreshVersions();
@@ -137,13 +176,25 @@ export function useStreamChat({
         });
       } catch (error) {
         console.error("[CHAT] Exception during streaming setup:", error);
-        setIsStreaming(false);
+        setIsStreamingById((prev) => {
-        setError(error instanceof Error ? error.message : String(error));
+          const next = new Map(prev);
+          if (chatId) next.set(chatId, false);
+          return next;
+        });
+        setErrorById((prev) => {
+          const next = new Map(prev);
+          if (chatId)
+            next.set(
+              chatId,
+              error instanceof Error ? error.message : String(error),
+            );
+          return next;
+        });
       }
     },
     [
-      setMessages,
+      setMessagesById,
-      setIsStreaming,
+      setIsStreamingById,
       setIsPreviewOpen,
       checkProblems,
       selectedAppId,
@@ -154,9 +205,25 @@ export function useStreamChat({
 
   return {
     streamMessage,
-    isStreaming,
+    isStreaming:
-    error,
+      hasChatId && chatId !== undefined
-    setError,
+        ? (isStreamingById.get(chatId) ?? false)
-    setIsStreaming,
+        : false,
+    error:
+      hasChatId && chatId !== undefined
+        ? (errorById.get(chatId) ?? null)
+        : null,
+    setError: (value: string | null) =>
+      setErrorById((prev) => {
+        const next = new Map(prev);
+        if (chatId !== undefined) next.set(chatId, value);
+        return next;
+      }),
+    setIsStreaming: (value: boolean) =>
+      setIsStreamingById((prev) => {
+        const next = new Map(prev);
+        if (chatId !== undefined) next.set(chatId, value);
+        return next;
+      }),
   };
 }

src/hooks/useVersions.ts

@@ -1,9 +1,9 @@
 import { useEffect } from "react";
-import { useAtom, useAtomValue } from "jotai";
+import { useAtom, useAtomValue, useSetAtom } from "jotai";
 import { versionsListAtom } from "@/atoms/appAtoms";
 import { IpcClient } from "@/ipc/ipc_client";
 
-import { chatMessagesAtom, selectedChatIdAtom } from "@/atoms/chatAtoms";
+import { chatMessagesByIdAtom, selectedChatIdAtom } from "@/atoms/chatAtoms";
 import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
 import type { RevertVersionResponse, Version } from "@/ipc/ipc_types";
 import { toast } from "sonner";
@@ -11,7 +11,7 @@ import { toast } from "sonner";
 export function useVersions(appId: number | null) {
   const [, setVersionsAtom] = useAtom(versionsListAtom);
   const selectedChatId = useAtomValue(selectedChatIdAtom);
-  const [, setMessages] = useAtom(chatMessagesAtom);
+  const setMessagesById = useSetAtom(chatMessagesByIdAtom);
   const queryClient = useQueryClient();
 
   const {
@@ -67,7 +67,11 @@ export function useVersions(appId: number | null) {
       });
       if (selectedChatId) {
         const chat = await IpcClient.getInstance().getChat(selectedChatId);
-        setMessages(chat.messages);
+        setMessagesById((prev) => {
+          const next = new Map(prev);
+          next.set(selectedChatId, chat.messages);
+          return next;
+        });
       }
       await queryClient.invalidateQueries({
         queryKey: ["problems", appId],

src/ipc/handlers/chat_stream_handlers.ts

@@ -206,7 +206,6 @@ export function registerChatStreamHandlers() {
   ipcMain.handle("chat:stream", async (event, req: ChatStreamParams) => {
     try {
       const fileUploadsState = FileUploadsState.getInstance();
-      fileUploadsState.initialize({ chatId: req.chatId });
 
       // Create an AbortController for this stream
       const abortController = new AbortController();
@@ -288,10 +287,13 @@ export function registerChatStreamHandlers() {
             // For upload-to-codebase, create a unique file ID and store the mapping
             const fileId = `DYAD_ATTACHMENT_${index}`;
 
-            fileUploadsState.addFileUpload(fileId, {
+            fileUploadsState.addFileUpload(
+              { chatId: req.chatId, fileId },
+              {
                 filePath,
                 originalName: attachment.name,
-            });
+              },
+            );
 
             // Add instruction for AI to use dyad-write tag
             attachmentInfo += `\n\nFile to upload to codebase: ${attachment.name} (file id: ${fileId})\n`;
@@ -793,10 +795,10 @@ This conversation includes one or more image attachments. When the user uploads
               const requestIdPrefix = isEngineEnabled
                 ? `[Request ID: ${dyadRequestId}] `
                 : "";
-              event.sender.send(
+              event.sender.send("chat:response:error", {
-                "chat:response:error",
+                chatId: req.chatId,
-                `Sorry, there was an error from the AI: ${requestIdPrefix}${message}`,
+                error: `Sorry, there was an error from the AI: ${requestIdPrefix}${message}`,
-              );
+              });
               // Clean up the abort controller
               activeStreams.delete(req.chatId);
             },
@@ -804,6 +806,8 @@ This conversation includes one or more image attachments. When the user uploads
           });
         };
 
+        let lastDbSaveAt = 0;
+
         const processResponseChunkUpdate = async ({
           fullResponse,
         }: {
@@ -823,6 +827,16 @@ This conversation includes one or more image attachments. When the user uploads
           }
           // Store the current partial response
           partialResponses.set(req.chatId, fullResponse);
+          // Save to DB (in case user is switching chats during the stream)
+          const now = Date.now();
+          if (now - lastDbSaveAt >= 150) {
+            await db
+              .update(messages)
+              .set({ content: fullResponse })
+              .where(eq(messages.id, placeholderAssistantMessage.id));
+
+            lastDbSaveAt = now;
+          }
 
           // Update the placeholder assistant message content in the messages array
           const currentMessages = [...updatedChat.messages];
@@ -1143,11 +1157,10 @@ ${problemReport.problems
           });
 
           if (status.error) {
-            safeSend(
+            safeSend(event.sender, "chat:response:error", {
-              event.sender,
+              chatId: req.chatId,
-              "chat:response:error",
+              error: `Sorry, there was an error applying the AI's changes: ${status.error}`,
-              `Sorry, there was an error applying the AI's changes: ${status.error}`,
+            });
-            );
           }
 
           // Signal that the stream has completed
@@ -1190,15 +1203,14 @@ ${problemReport.problems
       return req.chatId;
     } catch (error) {
       logger.error("Error calling LLM:", error);
-      safeSend(
+      safeSend(event.sender, "chat:response:error", {
-        event.sender,
+        chatId: req.chatId,
-        "chat:response:error",
+        error: `Sorry, there was an error processing your request: ${error}`,
-        `Sorry, there was an error processing your request: ${error}`,
+      });
-      );
       // Clean up the abort controller
       activeStreams.delete(req.chatId);
       // Clean up file uploads state on error
-      FileUploadsState.getInstance().clear();
+      FileUploadsState.getInstance().clear(req.chatId);
       return "error";
     }
   });
@@ -1222,6 +1234,11 @@ ${problemReport.problems
       updatedFiles: false,
     } satisfies ChatResponseEnd);
 
+    // Clean up uploads state for this chat
+    try {
+      FileUploadsState.getInstance().clear(chatId);
+    } catch {}
+
     return true;
   });
 }

src/ipc/ipc_client.ts

@@ -189,15 +189,27 @@ export class IpcClient {
       }
     });
 
-    this.ipcRenderer.on("chat:response:error", (error) => {
+    this.ipcRenderer.on("chat:response:error", (payload) => {
       console.debug("chat:response:error");
-      if (typeof error === "string") {
+      if (
-        for (const [chatId, callbacks] of this.chatStreams.entries()) {
+        payload &&
+        typeof payload === "object" &&
+        "chatId" in payload &&
+        "error" in payload
+      ) {
+        const { chatId, error } = payload as { chatId: number; error: string };
+        const callbacks = this.chatStreams.get(chatId);
+        if (callbacks) {
           callbacks.onError(error);
           this.chatStreams.delete(chatId);
+        } else {
+          console.warn(
+            `[IPC] No callbacks found for chat ${chatId} on error`,
+            this.chatStreams,
+          );
         }
       } else {
-        console.error("[IPC] Invalid error data received:", error);
+        console.error("[IPC] Invalid error data received:", payload);
       }
     });
 

src/ipc/processors/response_processor.ts

@@ -68,7 +68,7 @@ export async function processFullResponseActions(
 }> {
   const fileUploadsState = FileUploadsState.getInstance();
   const fileUploadsMap = fileUploadsState.getFileUploadsForChat(chatId);
-  fileUploadsState.clear();
+  fileUploadsState.clear(chatId);
   logger.log("processFullResponseActions for chatId", chatId);
   // Get the app associated with the chat
   const chatWithApp = await db.query.chats.findFirst({

src/ipc/utils/file_uploads_state.ts

@@ -9,8 +9,8 @@ export interface FileUploadInfo {
 
 export class FileUploadsState {
   private static instance: FileUploadsState;
-  private currentChatId: number | null = null;
+  // Map of chatId -> (fileId -> fileInfo)
-  private fileUploadsMap = new Map<string, FileUploadInfo>();
+  private uploadsByChat = new Map<number, Map<string, FileUploadInfo>>();
 
   private constructor() {}
 
@@ -22,45 +22,54 @@ export class FileUploadsState {
   }
 
   /**
-   * Initialize file uploads state for a specific chat and message
+   * Ensure a map exists for a chatId
    */
-  public initialize({ chatId }: { chatId: number }): void {
+  private ensureChat(chatId: number): Map<string, FileUploadInfo> {
-    this.currentChatId = chatId;
+    let map = this.uploadsByChat.get(chatId);
-    this.fileUploadsMap.clear();
+    if (!map) {
-    logger.debug(`Initialized file uploads state for chat ${chatId}`);
+      map = new Map<string, FileUploadInfo>();
+      this.uploadsByChat.set(chatId, map);
+    }
+    return map;
   }
 
   /**
-   * Add a file upload mapping
+   * Add a file upload mapping to a specific chat
    */
-  public addFileUpload(fileId: string, fileInfo: FileUploadInfo): void {
+  public addFileUpload(
-    this.fileUploadsMap.set(fileId, fileInfo);
+    { chatId, fileId }: { chatId: number; fileId: string },
-    logger.log(`Added file upload: ${fileId} -> ${fileInfo.originalName}`);
+    fileInfo: FileUploadInfo,
+  ): void {
+    const map = this.ensureChat(chatId);
+    map.set(fileId, fileInfo);
+    logger.log(
+      `Added file upload for chat ${chatId}: ${fileId} -> ${fileInfo.originalName}`,
+    );
   }
 
   /**
-   * Get the current file uploads map
+   * Get a copy of the file uploads map for a specific chat
    */
   public getFileUploadsForChat(chatId: number): Map<string, FileUploadInfo> {
-    if (this.currentChatId !== chatId) {
+    const map = this.uploadsByChat.get(chatId);
-      return new Map();
+    return new Map(map ?? []);
   }
-    return new Map(this.fileUploadsMap);
+
+  // Removed getCurrentChatId(): no longer applicable in per-chat state
+
+  /**
+   * Clear state for a specific chat
+   */
+  public clear(chatId: number): void {
+    this.uploadsByChat.delete(chatId);
+    logger.debug(`Cleared file uploads state for chat ${chatId}`);
   }
 
   /**
-   * Get current chat ID
+   * Clear all uploads (primarily for tests or full reset)
    */
-  public getCurrentChatId(): number | null {
+  public clearAll(): void {
-    return this.currentChatId;
+    this.uploadsByChat.clear();
-  }
+    logger.debug("Cleared all file uploads state");
-
-  /**
-   * Clear the current state
-   */
-  public clear(): void {
-    this.currentChatId = null;
-    this.fileUploadsMap.clear();
-    logger.debug("Cleared file uploads state");
   }
 }

testing/fake-llm-server/chatCompletionHandler.ts

@@ -6,7 +6,7 @@ import { CANNED_MESSAGE, createStreamChunk } from ".";
 let globalCounter = 0;
 
 export const createChatCompletionHandler =
-  (prefix: string) => (req: Request, res: Response) => {
+  (prefix: string) => async (req: Request, res: Response) => {
     const { stream = false, messages = [] } = req.body;
     console.log("* Received messages", messages);
 
@@ -42,6 +42,14 @@ DYAD_ATTACHMENT_0
       messageContent += "\n\n" + generateDump(req);
     }
 
+    if (
+      lastMessage &&
+      typeof lastMessage.content === "string" &&
+      lastMessage.content.includes("[sleep=medium]")
+    ) {
+      await new Promise((resolve) => setTimeout(resolve, 10_000));
+    }
+
     // TS auto-fix prefixes
     if (
       lastMessage &&
@@ -145,7 +153,8 @@ export default Index;
       typeof lastMessage.content === "string" &&
       lastMessage.content.startsWith("tc=")
     ) {
-      const testCaseName = lastMessage.content.slice(3); // Remove "tc=" prefix
+      const testCaseName = lastMessage.content.slice(3).split("[")[0].trim(); // Remove "tc=" prefix
+      console.error(`* Loading test case: ${testCaseName}`);
       const testFilePath = path.join(
         __dirname,
         "..",
@@ -162,7 +171,7 @@ export default Index;
           messageContent = fs.readFileSync(testFilePath, "utf-8");
           console.log(`* Loaded test case: ${testCaseName}`);
         } else {
-          console.log(`* Test case file not found: ${testFilePath}`);
+          console.error(`* Test case file not found: ${testFilePath}`);
           messageContent = `Error: Test case file not found: ${testCaseName}.md`;
         }
       } catch (error) {