diff --git a/apps/web/src/components/ai-sidebar/AiAgentSelector.tsx b/apps/web/src/components/ai-sidebar/AiAgentSelector.tsx
new file mode 100644
index 00000000..a24691ba
--- /dev/null
+++ b/apps/web/src/components/ai-sidebar/AiAgentSelector.tsx
@@ -0,0 +1,142 @@
+import { useEffect, useState } from "react";
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { ChevronDown, Loader2 } from "lucide-react";
+import { Link } from "react-router";
+import { WORKSPACE_SETTINGS_PATH } from "@/hooks/useWorkspaceRoute";
+import { useTranslation } from "react-i18next";
+import {
+  DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuLabel, DropdownMenuRadioGroup,
+  DropdownMenuRadioItem, DropdownMenuSeparator, DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
+import { api } from "@/lib/api";
+import {
+  AI_SIDEBAR_ADAPTER_PATH_KEY, aiSidebarAdapterFromStorage,
+  desktopAcpAvailable, listDesktopAcpAdapters, probeDesktopAcpAdapter, selectAiSidebarAgent,
+  type AiSidebarSource, type DesktopAcpAdapterId,
+} from "@/lib/desktop-acp";
+import { aiErrorMessage, formatProviderOrdinal, isLegacyProviderDisplayName } from "../settings/ai-provider-options";
+import { resolveBuiltinAgentModel } from "./builtin-agent-model";
+
+export function AiAgentSelector({ source, adapterId, disabled, onPendingChange, noteContext = false }: {
+  source: AiSidebarSource;
+  adapterId: DesktopAcpAdapterId | null;
+  disabled: boolean;
+  noteContext?: boolean;
+  onPendingChange: (pending: boolean) => void;
+}) {
+  const { t, i18n } = useTranslation();
+  const locale = i18n.resolvedLanguage ?? i18n.language;
+  const queryClient = useQueryClient();
+  const [open, setOpen] = useState(false);
+  const settings = useQuery({ queryKey: ["ai-settings", locale], queryFn: () => api.getAiSettings(locale), staleTime: 30_000 });
+  const desktop = desktopAcpAvailable();
+  const agents = useQuery({
+    queryKey: ["ai-sidebar-adapters"],
+    queryFn: async () => {
+      const listed = await listDesktopAcpAdapters();
+      const configured = aiSidebarAdapterFromStorage("antigravity", window.localStorage.getItem(AI_SIDEBAR_ADAPTER_PATH_KEY));
+      if (configured?.id === "antigravity" && configured.path) {
+        const checked = await probeDesktopAcpAdapter(configured);
+        return [...listed.filter((agent) => agent.id !== checked.id), checked];
+      }
+      return listed;
+    },
+    enabled: desktop && open,
+    staleTime: 0,
+  });
+  const mutation = useMutation({
+    mutationFn: async (value: string) => {
+      if (value.startsWith("agent:")) {
+        const id = value.slice(6) as DesktopAcpAdapterId;
+        if (!agents.data?.some((agent) => agent.id === id && agent.state === "available")) throw new Error(t("aiAssistant.agentSource.switchUnavailable"));
+        selectAiSidebarAgent("local", id);
+      } else {
+        if (value !== "builtin" && value.slice(6) !== settings.data?.defaultModelId) {
+          const updated = await api.updateDefaultAiModel(value.slice(6));
+          queryClient.setQueryData(["ai-settings", locale], updated);
+          await queryClient.invalidateQueries({ queryKey: ["ai-settings"] });
+        }
+        selectAiSidebarAgent("builtin");
+      }
+    },
+    onSuccess: () => setOpen(false),
+  });
+  useEffect(() => {
+    if (disabled) setOpen(false);
+  }, [disabled]);
+  const builtin = resolveBuiltinAgentModel(settings.data);
+  const provider = settings.data?.providers.find((item) => item.models.some((model) => model.id === settings.data?.defaultModelId));
+  const modelLabel = [provider?.displayName, builtin?.label].filter(Boolean).join(" · ") || t("aiModel.noDefaultModel");
+  const label = source === "local"
+    ? (adapterId ? t(`aiAssistant.agentSource.${adapterId}`) : t("aiAssistant.agentSource.local"))
+    : `${t("aiAssistant.agentSource.builtin")} · ${modelLabel}`;
+  const buttonLabel = source === "local" ? label : builtin?.label ?? t("aiModel.noDefaultModel");
+  const localHint = t(noteContext ? "aiAssistant.agentSource.switchNoteAgentHint" : "aiAssistant.agentSource.newAgentThread");
+  const selected = source === "local" ? `agent:${adapterId}` : settings.data?.defaultModelId ? `model:${settings.data.defaultModelId}` : "builtin";
+  const providers = (settings.data?.providers ?? []).map((provider, index) => {
+    const name = !provider.displayName || isLegacyProviderDisplayName(provider.displayName, provider.provider)
+      ? t("aiModel.defaultProviderName", { ordinal: formatProviderOrdinal(index + 1, locale) }) : provider.displayName;
+    return { ...provider, name };
+  }).filter((provider) => provider.models.length);
+  const localAgents = agents.data ?? [];
+  const choose = (value: string) => {
+    if (disabled || mutation.isPending) return;
+    if (value === selected) { setOpen(false); return; }
+    onPendingChange(true);
+    void mutation.mutateAsync(value).catch(() => undefined).finally(() => onPendingChange(false));
+  };
+
+  return (
+    <div className="min-w-0 max-w-44 flex-1">
+      <DropdownMenu open={open} onOpenChange={(next) => {
+        if (mutation.isPending) return;
+        setOpen(next);
+        if (next) { mutation.reset(); void settings.refetch(); }
+      }}>
+        <DropdownMenuTrigger asChild>
+          <button type="button" disabled={disabled || mutation.isPending}
+            aria-label={`${t("aiAssistant.agentSource.switch")} · ${label}`}
+            className="flex w-full min-w-0 items-center gap-1 rounded-full px-2 py-1.5 text-xs text-slate-600 hover:bg-slate-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-slate-400 disabled:opacity-50">
+            <span className="truncate">{buttonLabel}</span>
+            {mutation.isPending ? <Loader2 className="size-3 shrink-0 animate-spin" /> : <ChevronDown className="size-3 shrink-0" />}
+          </button>
+        </DropdownMenuTrigger>
+        <DropdownMenuContent side="top" align="end" className="w-80 max-w-[calc(100vw-24px)]">
+          {settings.isError || mutation.isError ? <p role="alert" className="px-2 py-1 text-xs text-rose-600">{aiErrorMessage(mutation.error ?? settings.error, t("aiAssistant.agentSource.switchUnavailable"), t("aiModel.encryptionKeyMissing"), t("aiModel.savedCredentialsUnavailable"))}</p> : null}
+          <div className="max-h-72 overflow-y-auto">
+            <DropdownMenuRadioGroup value={selected} onValueChange={choose}>
+              {source === "local" ? <DropdownMenuRadioItem value="builtin" disabled={mutation.isPending} onSelect={(event) => event.preventDefault()}>{t("aiAssistant.agentSource.builtin")}</DropdownMenuRadioItem> : null}
+              {settings.isPending ? <p className="px-2 py-2 text-xs">{t("common.loading")}</p> : null}
+              {providers.map((provider) => (
+                <div key={provider.id}>
+                  <DropdownMenuLabel>{t("aiAssistant.agentSource.builtin")} · {provider.name}</DropdownMenuLabel>
+                  {provider.models.map((model) => <DropdownMenuRadioItem key={model.id} value={`model:${model.id}`}
+                    disabled={mutation.isPending || settings.data?.readOnly || !settings.data?.encryptionConfigured || !provider.isEnabled || provider.credentialsUnavailable}
+                    onSelect={(event) => event.preventDefault()}>
+                    <span className="min-w-0 break-words">{model.displayName || model.modelId}{!provider.isEnabled || provider.credentialsUnavailable ? <span className="ml-2 text-[10px] text-slate-500">{t("aiAssistant.agentSource.optionUnavailable")}</span> : null}</span>
+                  </DropdownMenuRadioItem>)}
+                </div>
+              ))}
+              {!settings.isPending && !providers.length ? <p className="px-2 py-2 text-xs text-slate-500">{t("aiAssistant.agentSource.noModels")}</p> : null}
+              {desktop ? <>
+                <DropdownMenuSeparator />
+                <DropdownMenuLabel>{t("aiAssistant.agentSource.local")}</DropdownMenuLabel>
+                <p className="px-2 pb-1 text-[11px] text-slate-500">{localHint}</p>
+                {agents.isPending ? <p className="px-2 py-2 text-xs">{t("common.loading")}</p> : null}
+                {agents.isError ? <p role="alert" className="px-2 py-2 text-xs text-rose-600">{t("aiAssistant.agentSource.switchUnavailable")}</p> : null}
+                {localAgents.map((agent) => <DropdownMenuRadioItem key={agent.id} value={`agent:${agent.id}`} disabled={mutation.isPending || agents.isFetching || agent.state !== "available"} onSelect={(event) => event.preventDefault()}>
+                  <span className="flex min-w-0 flex-1 flex-wrap justify-between gap-x-2"><span>{t(`aiAssistant.agentSource.${agent.id}`)}</span><span className="text-[10px] text-slate-500">{t(`aiAssistant.agentSource.states.${agent.state}`)}</span></span>
+                </DropdownMenuRadioItem>)}
+                {!agents.isPending && !agents.isError && !localAgents.length ? <p className="px-2 py-2 text-xs text-slate-500">{t("aiAssistant.agentSource.switchUnavailable")}</p> : null}
+              </> : null}
+            </DropdownMenuRadioGroup>
+          </div>
+          <DropdownMenuSeparator />
+          <DropdownMenuItem asChild disabled={mutation.isPending}>
+            <Link to={`${WORKSPACE_SETTINGS_PATH}?tab=ai`}>{t("aiAssistant.agentSource.configure")}</Link>
+          </DropdownMenuItem>
+        </DropdownMenuContent>
+      </DropdownMenu>
+    </div>
+  );
+}
diff --git a/apps/web/src/components/ai-sidebar/AiSidebar.tsx b/apps/web/src/components/ai-sidebar/AiSidebar.tsx
index 5189e878..abfde4b7 100644
--- a/apps/web/src/components/ai-sidebar/AiSidebar.tsx
+++ b/apps/web/src/components/ai-sidebar/AiSidebar.tsx
@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useMemo, useRef, useState, type ClipboardEvent, type MouseEvent, type PointerEvent as ReactPointerEvent, type RefObject } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState, type ClipboardEvent, type MouseEvent, type PointerEvent as ReactPointerEvent, type RefObject, type ReactNode } from "react";
 import { AnimatePresence } from "motion/react";
 import * as m from "motion/react-m";
 import { useTranslation } from "react-i18next";
@@ -48,6 +48,7 @@ import {
 } from "@/lib/ai-attachments";
 import { companionLocale } from "@/lib/companion-locale";
 import {
+  AI_SIDEBAR_SELECTION_EVENT,
   AI_SIDEBAR_LOCAL_THREAD_KEY,
   AI_SIDEBAR_LOCAL_THREADS_KEY,
   AI_SIDEBAR_OPEN_KEY,
@@ -58,6 +59,7 @@ import {
   readAiSidebarAdapter,
   readAiSidebarSource,
   subscribeDesktopAcp,
+  startsNewLocalAgentThread,
   type DesktopAcpEvent,
 } from "@/lib/desktop-acp";
 import {
@@ -84,7 +86,7 @@ import { CompanionQuestionForm } from "../CompanionQuestionForm";
 import { CompanionCreatedNoteLinks } from "../CompanionCreatedNoteLinks";
 import { AiSidebarMessage } from "./AiSidebarMessage";
 import { AiSidebarLocalProcess } from "./AiSidebarLocalProcess";
-import { BuiltinAgentStatus } from "./BuiltinAgentStatus";
+import { AiAgentSelector } from "./AiAgentSelector";
 import { InfographicSidebarSession, type InfographicSidebarController } from "./InfographicSidebarSession";
 import { memoIdFromSidebarLinkEvent } from "./sidebar-note-links";
 
@@ -565,6 +567,7 @@ function SidebarComposer({
   onStop,
   skillPrompt,
   focusToken,
+  aiSelector,
 }: {
   attachments: PendingAttachment[];
   attachmentError: string | null;
@@ -580,6 +583,7 @@ function SidebarComposer({
   onStop: () => void;
   skillPrompt: (id: SkillId, rest?: string) => string;
   focusToken: number;
+  aiSelector: ReactNode;
 }) {
   const { t } = useTranslation();
   const { textInput } = usePromptInputController();
@@ -665,7 +669,7 @@ function SidebarComposer({
           onPaste={onPaste}
         />
         <PromptInputFooter className="px-2.5 pb-2.5 pt-0">
-          <PromptInputTools>
+          <PromptInputTools className="shrink-0">
             <TooltipProvider delayDuration={300}>
               <Tooltip>
                 <TooltipTrigger asChild>
@@ -699,20 +703,23 @@ function SidebarComposer({
               </Button>
             ) : null}
           </PromptInputTools>
-          {busy ? (
-            <Button type="button" size="sm" variant="outline" onClick={onStop}>
-              {t("aiAssistant.sidebar.stop")}
-            </Button>
-          ) : (
-            <PromptInputSubmit
-              aria-label={t("companion.send")}
-              className="rounded-full border-slate-900 bg-slate-900 text-slate-50 hover:border-slate-800 hover:bg-slate-800 disabled:border-slate-100 disabled:bg-slate-100 disabled:text-slate-300"
-              disabled={locked || !draft.trim()}
-              variant="solid"
-            >
-              <ArrowUp className="size-4" />
-            </PromptInputSubmit>
-          )}
+          <div className="ml-auto flex min-w-0 flex-1 items-center justify-end gap-1">
+            {aiSelector}
+            {busy ? (
+              <Button type="button" size="sm" variant="outline" onClick={onStop}>
+                {t("aiAssistant.sidebar.stop")}
+              </Button>
+            ) : (
+              <PromptInputSubmit
+                aria-label={t("companion.send")}
+                className="rounded-full border-slate-900 bg-slate-900 text-slate-50 hover:border-slate-800 hover:bg-slate-800 disabled:border-slate-100 disabled:bg-slate-100 disabled:text-slate-300"
+                disabled={locked || !draft.trim()}
+                variant="solid"
+              >
+                <ArrowUp className="size-4" />
+              </PromptInputSubmit>
+            )}
+          </div>
         </PromptInputFooter>
       </PromptInput>
       <input
@@ -777,6 +784,9 @@ function AiSidebarSession({
   const [attachmentError, setAttachmentError] = useState<string | null>(null);
   const [conflicts, setConflicts] = useState<Record<string, string>>({});
   const [busy, setBusy] = useState(false);
+  const [selectionPending, setSelectionPending] = useState(false);
+  const selectionPendingRef = useRef(false);
+  const previousAgent = useRef({ source, adapterId: localAdapterId });
   const [acting, setActing] = useState(false);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
@@ -1000,18 +1010,32 @@ function AiSidebarSession({
 
   useEffect(() => {
     const syncSource = () => {
-      setSource(readAiSidebarSource());
-      setLocalAdapterId(readLocalAdapter()?.id ?? null);
+      if (locked.current) return;
+      const nextSource = readAiSidebarSource();
+      const nextAdapter = readLocalAdapter()?.id ?? null;
+      const previous = previousAgent.current;
+      if (startsNewLocalAgentThread(previous, { source: nextSource, adapterId: nextAdapter })) {
+        const id = createClientUuid();
+        setLocalThreadId(id);
+        localThreadIdRef.current = id;
+        writeStorage(AI_SIDEBAR_LOCAL_THREAD_KEY, id);
+      }
+      previousAgent.current = { source: nextSource, adapterId: nextAdapter };
+      setSource(nextSource);
+      setLocalAdapterId(nextAdapter);
+      if (previous.source !== nextSource || previous.adapterId !== nextAdapter) setError(null);
     };
     syncSource();
     if (!open) return;
     window.addEventListener("focus", syncSource);
     window.addEventListener("storage", syncSource);
+    window.addEventListener(AI_SIDEBAR_SELECTION_EVENT, syncSource);
     return () => {
       window.removeEventListener("focus", syncSource);
       window.removeEventListener("storage", syncSource);
+      window.removeEventListener(AI_SIDEBAR_SELECTION_EVENT, syncSource);
     };
-  }, [open]);
+  }, [open, busy]);
 
   useEffect(() => {
     if (!companionAvailable || source === "local") {
@@ -1103,7 +1127,7 @@ function AiSidebarSession({
 
   const launch = useCallback(async (message: string, options?: { includeCurrentNote?: boolean; readOnly?: boolean }): Promise<string> => {
     const text = message.trim();
-    if (!text || locked.current) throw new Error("busy");
+    if (!text || locked.current || selectionPendingRef.current) throw new Error("busy");
     const useCurrentNote = options?.includeCurrentNote ?? includeCurrentNote;
     const focusAtSend = focusRef.current;
     const mode = readAiSidebarSource();
@@ -1525,28 +1549,10 @@ function AiSidebarSession({
             if (companionThreads.some((thread) => thread.id === threadId)) rememberThread(createClientUuid());
           }}
         />
-        {source === "local" ? (
-          <TooltipProvider delayDuration={300}>
-            <Tooltip>
-              <TooltipTrigger asChild>
-                <span
-                  className="ml-auto min-w-0 max-w-[46%] shrink truncate rounded-sm text-right text-xs text-slate-500 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-slate-400"
-                  data-ai-local-agent=""
-                  tabIndex={0}
-                >
-                  {localAdapterId ? t(`aiAssistant.agentSource.${localAdapterId}`) : t("aiAssistant.sidebar.localStatus")}
-                </span>
-              </TooltipTrigger>
-              <TooltipContent className="max-w-xs">
-                <p>{localAdapterId ? t(`aiAssistant.agentSource.${localAdapterId}`) : t("aiAssistant.sidebar.localStatus")}</p>
-                <p className="mt-1">{t("aiAssistant.agentSource.localHint")}</p>
-              </TooltipContent>
-            </Tooltip>
-          </TooltipProvider>
-        ) : <BuiltinAgentStatus />}
         <Button
           type="button"
           size="icon-sm"
+          className="ml-auto shrink-0"
           variant="ghost"
           title={t("aiAssistant.sidebar.close")}
           aria-label={t("aiAssistant.sidebar.close")}
@@ -1716,7 +1722,7 @@ function AiSidebarSession({
             attachments={attachments}
             attachmentError={attachmentError}
             busy={running}
-            locked={acting}
+            locked={acting || selectionPending}
             includeCurrentNote={includeCurrentNote}
             currentNoteAvailable={Boolean(noteTitle?.trim() || contentMarkdown?.trim())}
             onIncludeCurrentNoteChange={setIncludeCurrentNote}
@@ -1726,6 +1732,17 @@ function AiSidebarSession({
             onLaunch={launch}
             onStop={() => { void stop(); }}
             skillPrompt={skillPrompt}
+            aiSelector={
+              <AiAgentSelector
+                source={source}
+                adapterId={localAdapterId}
+                disabled={running || acting || loading}
+                onPendingChange={(pending) => {
+                  selectionPendingRef.current = pending;
+                  setSelectionPending(pending);
+                }}
+              />
+            }
             focusToken={composerFocusToken}
           />
         </PromptInputProvider>
diff --git a/apps/web/src/components/ai-sidebar/InfographicSidebarSession.tsx b/apps/web/src/components/ai-sidebar/InfographicSidebarSession.tsx
index 5b1ca3a0..c3a2de0c 100644
--- a/apps/web/src/components/ai-sidebar/InfographicSidebarSession.tsx
+++ b/apps/web/src/components/ai-sidebar/InfographicSidebarSession.tsx
@@ -1,6 +1,6 @@
 import { useTranslation } from "react-i18next";
 import { ArrowUp, PanelRightClose, Sparkles, Undo2 } from "lucide-react";
-import type { MouseEvent } from "react";
+import { useState, type MouseEvent } from "react";
 import type { InfographicConversationTurn } from "@edgeever/shared";
 import { Button } from "@/components/ui/button";
 import { Conversation, ConversationContent, ConversationEmptyState, ConversationScrollButton } from "@/components/ai-elements/conversation";
@@ -47,7 +47,7 @@ export type InfographicSidebarController = {
   onStop: () => void;
 };
 
-function InfographicSidebarComposer({ session }: { session: InfographicSidebarController }) {
+function InfographicSidebarComposer({ session, selectionPending, onPendingChange }: { session: InfographicSidebarController; selectionPending: boolean; onPendingChange: (pending: boolean) => void }) {
   const { t } = useTranslation();
   const { textInput } = usePromptInputController();
   const draft = textInput.value.trim();
@@ -56,39 +56,42 @@ function InfographicSidebarComposer({ session }: { session: InfographicSidebarCo
       inputGroupClassName="rounded-[22px] border-slate-200 bg-card shadow-sm has-[[data-slot=input-group-control]:focus-visible]:ring-0"
       onSubmit={async ({ text }) => {
         const raw = text.trim().slice(0, 1000);
-        if (!raw || session.generating) throw new Error("empty");
+        if (!raw || session.generating || selectionPending) throw new Error("empty");
         await session.onSubmit(raw);
       }}
     >
       <PromptInputTextarea
         className="min-h-20 px-4 pb-2 pt-4 text-[13px] leading-5 md:text-[13px]"
-        disabled={session.generating}
+        disabled={session.generating || selectionPending}
         maxLength={1000}
         placeholder={t(session.hasGraphic ? "infographic.refinePrompt" : "infographic.prompt")}
       />
       <PromptInputFooter className="px-2.5 pb-2.5 pt-0">
-        <PromptInputTools>
+        <PromptInputTools className="shrink-0">
           {session.canUndo ? (
-            <Button type="button" size="sm" variant="outline" disabled={session.generating} onClick={session.onUndo}>
+            <Button type="button" size="sm" variant="outline" disabled={session.generating || selectionPending} onClick={session.onUndo}>
               <Undo2 className="mr-1 h-3.5 w-3.5" />
               {t("infographic.undoGeneration")}
             </Button>
           ) : null}
         </PromptInputTools>
-        {session.generating ? (
-          <Button type="button" size="sm" variant="outline" onClick={session.onStop}>
-            {t("aiAssistant.sidebar.stop")}
-          </Button>
-        ) : (
-          <PromptInputSubmit
-            aria-label={t(session.hasGraphic ? "infographic.applyRefinement" : "infographic.generate")}
-            className="rounded-full border-slate-900 bg-slate-900 text-slate-50 hover:border-slate-800 hover:bg-slate-800 disabled:border-slate-100 disabled:bg-slate-100 disabled:text-slate-300"
-            disabled={!draft}
-            variant="solid"
-          >
-            <ArrowUp className="size-4" />
-          </PromptInputSubmit>
-        )}
+        <div className="ml-auto flex min-w-0 flex-1 items-center justify-end gap-1">
+          <SidebarAgentModeStatus disabled={session.generating} onPendingChange={onPendingChange} />
+          {session.generating ? (
+            <Button type="button" size="sm" variant="outline" onClick={session.onStop}>
+              {t("aiAssistant.sidebar.stop")}
+            </Button>
+          ) : (
+            <PromptInputSubmit
+              aria-label={t(session.hasGraphic ? "infographic.applyRefinement" : "infographic.generate")}
+              className="rounded-full border-slate-900 bg-slate-900 text-slate-50 hover:border-slate-800 hover:bg-slate-800 disabled:border-slate-100 disabled:bg-slate-100 disabled:text-slate-300"
+              disabled={!draft || selectionPending}
+              variant="solid"
+            >
+              <ArrowUp className="size-4" />
+            </PromptInputSubmit>
+          )}
+        </div>
       </PromptInputFooter>
     </PromptInput>
   );
@@ -119,6 +122,7 @@ export function InfographicSidebarSession({
   onOpenNote?: (memoId: string, notebookId: string) => void;
 }) {
   const { t, i18n } = useTranslation();
+  const [selectionPending, setSelectionPending] = useState(false);
   const title = noteTitle?.trim() || t("infographic.name");
   const openLinkedNote = (event: MouseEvent<HTMLElement>) => {
     const linkedId = memoIdFromSidebarLinkEvent(event);
@@ -139,7 +143,6 @@ export function InfographicSidebarSession({
           <Sparkles className="size-3.5 shrink-0" aria-hidden="true" />
           <span className="truncate">{title}</span>
         </span>
-        <SidebarAgentModeStatus />
         <Button
           type="button"
           size="icon-sm"
@@ -199,7 +202,7 @@ export function InfographicSidebarSession({
       {!session.readOnly ? (
         <div className="shrink-0 p-3">
           <PromptInputProvider>
-            <InfographicSidebarComposer session={session} />
+            <InfographicSidebarComposer session={session} selectionPending={selectionPending} onPendingChange={setSelectionPending} />
           </PromptInputProvider>
         </div>
       ) : null}
diff --git a/apps/web/src/components/ai-sidebar/SidebarAgentModeStatus.tsx b/apps/web/src/components/ai-sidebar/SidebarAgentModeStatus.tsx
index 8e6f98e8..3cc6f9e6 100644
--- a/apps/web/src/components/ai-sidebar/SidebarAgentModeStatus.tsx
+++ b/apps/web/src/components/ai-sidebar/SidebarAgentModeStatus.tsx
@@ -1,13 +1,8 @@
 import { useEffect, useState } from "react";
-import { useTranslation } from "react-i18next";
-import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from "@/components/ui/tooltip";
-import { readAiSidebarAdapter, readAiSidebarSource, type AiSidebarSource } from "@/lib/desktop-acp";
-import { BuiltinAgentStatus } from "./BuiltinAgentStatus";
+import { AI_SIDEBAR_SELECTION_EVENT, readAiSidebarAdapter, readAiSidebarSource, type AiSidebarSource } from "@/lib/desktop-acp";
+import { AiAgentSelector } from "./AiAgentSelector";
 
-const chipClassName = "ml-auto min-w-0 max-w-[46%] shrink-0 truncate rounded-sm text-right text-[11px] leading-4 text-slate-500 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-slate-400";
-
-export function SidebarAgentModeStatus() {
-  const { t } = useTranslation();
+export function SidebarAgentModeStatus({ disabled, onPendingChange }: { disabled: boolean; onPendingChange: (pending: boolean) => void }) {
   const [source, setSource] = useState<AiSidebarSource>(readAiSidebarSource);
   const [adapterId, setAdapterId] = useState(() => readAiSidebarAdapter()?.id ?? null);
 
@@ -19,30 +14,15 @@ export function SidebarAgentModeStatus() {
     sync();
     window.addEventListener("focus", sync);
     window.addEventListener("storage", sync);
+    window.addEventListener(AI_SIDEBAR_SELECTION_EVENT, sync);
     document.addEventListener("visibilitychange", sync);
     return () => {
       window.removeEventListener("focus", sync);
       window.removeEventListener("storage", sync);
+      window.removeEventListener(AI_SIDEBAR_SELECTION_EVENT, sync);
       document.removeEventListener("visibilitychange", sync);
     };
   }, []);
 
-  if (source !== "local") return <BuiltinAgentStatus />;
-
-  const label = adapterId ? t(`aiAssistant.agentSource.${adapterId}`) : t("aiAssistant.sidebar.localStatus");
-  return (
-    <TooltipProvider delayDuration={300}>
-      <Tooltip>
-        <TooltipTrigger asChild>
-          <span className={chipClassName} data-ai-local-agent="" tabIndex={0} aria-label={label}>
-            {label}
-          </span>
-        </TooltipTrigger>
-        <TooltipContent className="max-w-xs" side="bottom">
-          <p>{label}</p>
-          <p className="mt-1">{t("aiAssistant.agentSource.localHint")}</p>
-        </TooltipContent>
-      </Tooltip>
-    </TooltipProvider>
-  );
+  return <AiAgentSelector noteContext source={source} adapterId={adapterId} disabled={disabled} onPendingChange={onPendingChange} />;
 }
diff --git a/apps/web/src/components/dialogs/AiAssistantDialog.test.mjs b/apps/web/src/components/dialogs/AiAssistantDialog.test.mjs
index 1ff73a50..a7ae13af 100644
--- a/apps/web/src/components/dialogs/AiAssistantDialog.test.mjs
+++ b/apps/web/src/components/dialogs/AiAssistantDialog.test.mjs
@@ -16,15 +16,14 @@ describe("AI assistant modes", () => {
     expect(sidebar).not.toContain("hidden w-0");
     expect(sidebar).toContain("props.infographic ? (");
     expect(sidebar).toContain("<InfographicSidebarSession");
-    expect(sidebar).toContain("<BuiltinAgentStatus");
+    expect(sidebar).toContain("<AiAgentSelector");
     const infographic = readFileSync(new URL("../ai-sidebar/InfographicSidebarSession.tsx", import.meta.url), "utf8");
     const mode = readFileSync(new URL("../ai-sidebar/SidebarAgentModeStatus.tsx", import.meta.url), "utf8");
     const status = readFileSync(new URL("../ai-sidebar/BuiltinAgentStatus.tsx", import.meta.url), "utf8");
     const pane = readFileSync(new URL("../InfographicEditorPane.tsx", import.meta.url), "utf8");
     expect(infographic).toContain("<SidebarAgentModeStatus");
     expect(mode).toContain("readAiSidebarSource");
-    expect(mode).toContain("<BuiltinAgentStatus");
-    expect(mode).toContain('data-ai-local-agent=""');
+    expect(mode).toContain("<AiAgentSelector");
     expect(pane).toContain('readAiSidebarSource() === "local"');
     expect(pane).toContain("noteAccess: false");
     expect(status).toContain('data-ai-builtin-agent=""');
diff --git a/apps/web/src/components/settings/DesktopAcpAgentCard.tsx b/apps/web/src/components/settings/DesktopAcpAgentCard.tsx
index 8c93693f..527827a5 100644
--- a/apps/web/src/components/settings/DesktopAcpAgentCard.tsx
+++ b/apps/web/src/components/settings/DesktopAcpAgentCard.tsx
@@ -9,6 +9,7 @@ import {
   AI_SIDEBAR_ADAPTER_KEY,
   AI_SIDEBAR_ADAPTER_PATH_KEY,
   AI_SIDEBAR_SOURCE_KEY,
+  AI_SIDEBAR_SELECTION_EVENT,
   displayedDesktopAcpAdapter,
   listDesktopAcpAdapters,
   installDesktopAcpAdapter,
@@ -99,6 +100,17 @@ const DesktopAcpAgentCardBody = ({ bridge }: { bridge: boolean }) => {
     setAdapterId(readAdapterId());
     setAdapterPath(localStorage.getItem(AI_SIDEBAR_ADAPTER_PATH_KEY) ?? "");
     setReady(true);
+    const sync = () => {
+      setSource(bridge && readSource() === "local" ? "local" : "builtin");
+      setAdapterId(readAdapterId());
+      setAdapterPath(localStorage.getItem(AI_SIDEBAR_ADAPTER_PATH_KEY) ?? "");
+    };
+    window.addEventListener(AI_SIDEBAR_SELECTION_EVENT, sync);
+    window.addEventListener("storage", sync);
+    return () => {
+      window.removeEventListener(AI_SIDEBAR_SELECTION_EVENT, sync);
+      window.removeEventListener("storage", sync);
+    };
   }, [bridge]);
 
   useEffect(() => {
@@ -106,6 +118,7 @@ const DesktopAcpAgentCardBody = ({ bridge }: { bridge: boolean }) => {
     localStorage.setItem(AI_SIDEBAR_SOURCE_KEY, source);
     localStorage.setItem(AI_SIDEBAR_ADAPTER_KEY, adapterId);
     localStorage.setItem(AI_SIDEBAR_ADAPTER_PATH_KEY, adapterPath);
+    window.dispatchEvent(new Event(AI_SIDEBAR_SELECTION_EVENT));
   }, [adapterId, adapterPath, ready, source]);
 
   useEffect(() => {
diff --git a/apps/web/src/lib/desktop-acp.test.mjs b/apps/web/src/lib/desktop-acp.test.mjs
index 8bd52807..68612052 100644
--- a/apps/web/src/lib/desktop-acp.test.mjs
+++ b/apps/web/src/lib/desktop-acp.test.mjs
@@ -30,3 +30,48 @@ test("a prompt-time login failure takes priority over an earlier successful sess
   const earlierProbe = { id: "grokBuild", label: "Grok Build", state: "available" };
   expect(displayedDesktopAcpAdapter({ id: "grokBuild", path: "", listed: [current], probed: earlierProbe })).toBe(current);
 });
+
+test("switching into an external agent starts a fresh chat without changing built-in chats", async () => {
+  const { startsNewLocalAgentThread } = await import("./desktop-acp.ts");
+  const builtin = { source: "builtin", adapterId: "codex" };
+  const codex = { source: "local", adapterId: "codex" };
+  const claude = { source: "local", adapterId: "claudeCode" };
+  expect(startsNewLocalAgentThread(builtin, codex)).toBe(true);
+  expect(startsNewLocalAgentThread(codex, claude)).toBe(true);
+  expect(startsNewLocalAgentThread(codex, codex)).toBe(false);
+  expect(startsNewLocalAgentThread(codex, builtin)).toBe(false);
+});
+
+test("agent selection reuses preference keys, preserves the custom path and notifies only after saving", async () => {
+  const { selectAiSidebarAgent, AI_SIDEBAR_SELECTION_EVENT, AI_SIDEBAR_SOURCE_KEY, AI_SIDEBAR_ADAPTER_KEY, AI_SIDEBAR_ADAPTER_PATH_KEY } = await import("./desktop-acp.ts");
+  const previousWindow = globalThis.window;
+  const data = new Map([[AI_SIDEBAR_SOURCE_KEY, "builtin"], [AI_SIDEBAR_ADAPTER_KEY, "codex"], [AI_SIDEBAR_ADAPTER_PATH_KEY, "/custom/antigravity"]]);
+  const snapshots = [];
+  let fail = false;
+  globalThis.window = {
+    localStorage: {
+      getItem: key => data.get(key) ?? null,
+      setItem: (key, value) => {
+        if (fail && key === AI_SIDEBAR_SOURCE_KEY) { fail = false; throw new Error("storage full"); }
+        data.set(key, value);
+      },
+      removeItem: key => data.delete(key),
+    },
+    dispatchEvent: event => snapshots.push({ type: event.type, source: data.get(AI_SIDEBAR_SOURCE_KEY), adapter: data.get(AI_SIDEBAR_ADAPTER_KEY) }),
+  };
+  try {
+    selectAiSidebarAgent("local", "claudeCode");
+    expect(snapshots).toEqual([{ type: AI_SIDEBAR_SELECTION_EVENT, source: "local", adapter: "claudeCode" }]);
+    expect(data.get(AI_SIDEBAR_ADAPTER_PATH_KEY)).toBe("/custom/antigravity");
+    selectAiSidebarAgent("builtin");
+    expect(data.get(AI_SIDEBAR_ADAPTER_KEY)).toBe("claudeCode");
+    fail = true;
+    expect(() => selectAiSidebarAgent("local", "codex")).toThrow("storage full");
+    expect(data.get(AI_SIDEBAR_SOURCE_KEY)).toBe("builtin");
+    expect(data.get(AI_SIDEBAR_ADAPTER_KEY)).toBe("claudeCode");
+    expect(snapshots).toHaveLength(2);
+  } finally {
+    if (previousWindow === undefined) delete globalThis.window;
+    else globalThis.window = previousWindow;
+  }
+});
diff --git a/apps/web/src/lib/desktop-acp.ts b/apps/web/src/lib/desktop-acp.ts
index ce208309..19f889ef 100644
--- a/apps/web/src/lib/desktop-acp.ts
+++ b/apps/web/src/lib/desktop-acp.ts
@@ -75,9 +75,15 @@ export const AI_SIDEBAR_LOCAL_THREADS_KEY = "edgeever.aiSidebar.localThreads";
 export const AI_SIDEBAR_SOURCE_KEY = "edgeever.aiSidebar.source";
 export const AI_SIDEBAR_ADAPTER_KEY = "edgeever.aiSidebar.adapterId";
 export const AI_SIDEBAR_ADAPTER_PATH_KEY = "edgeever.aiSidebar.adapterPath";
+export const AI_SIDEBAR_SELECTION_EVENT = "edgeever:ai-sidebar-selection";
 
 export type AiSidebarSource = "builtin" | "local";
 
+export const startsNewLocalAgentThread = (
+  previous: { source: AiSidebarSource; adapterId: DesktopAcpAdapterId | null },
+  next: { source: AiSidebarSource; adapterId: DesktopAcpAdapterId | null },
+) => next.source === "local" && (previous.source !== "local" || previous.adapterId !== next.adapterId);
+
 const AI_SIDEBAR_ADAPTER_IDS = new Set<string>([
   "codex", "claudeCode", "antigravity", "openClaw", "hermesAgent", "grokBuild", "deepseekHarness", "piAgent", "workbuddyCn", "workbuddyIntl",
 ]);
@@ -111,6 +117,27 @@ export const readAiSidebarAdapter = () => aiSidebarAdapterFromStorage(
   readStorageItem(AI_SIDEBAR_ADAPTER_PATH_KEY),
 );
 
+// Keep the settings page and sidebar on the same existing preference keys.
+export const selectAiSidebarAgent = (source: AiSidebarSource, adapterId?: DesktopAcpAdapterId) => {
+  const storage = window.localStorage;
+  const previousSource = storage.getItem(AI_SIDEBAR_SOURCE_KEY);
+  const previousAdapter = storage.getItem(AI_SIDEBAR_ADAPTER_KEY);
+  try {
+    if (adapterId) storage.setItem(AI_SIDEBAR_ADAPTER_KEY, adapterId);
+    storage.setItem(AI_SIDEBAR_SOURCE_KEY, source);
+  } catch (error) {
+    try {
+      const preferences: Array<[string, string | null]> = [[AI_SIDEBAR_SOURCE_KEY, previousSource], [AI_SIDEBAR_ADAPTER_KEY, previousAdapter]];
+      for (const [key, value] of preferences) {
+        if (value === null) storage.removeItem(key);
+        else storage.setItem(key, value);
+      }
+    } catch { /* Report the original preference-write failure. */ }
+    throw error;
+  }
+  window.dispatchEvent(new Event(AI_SIDEBAR_SELECTION_EVENT));
+};
+
 const bridge = () => (typeof window === "undefined" ? undefined : window.edgeeverDesktop);
 
 export const desktopAcpAvailable = () => Boolean(bridge()?.listAcpAdapters);
diff --git a/packages/shared/src/i18n/en-US.ts b/packages/shared/src/i18n/en-US.ts
index f974e714..fed9fd42 100644
--- a/packages/shared/src/i18n/en-US.ts
+++ b/packages/shared/src/i18n/en-US.ts
@@ -1487,6 +1487,15 @@ export const enUS = {
       imageSaveFailed: "The image could not be saved locally. Download it now; it may be lost when you close this page.",
     },
     agentSource: {
+      configure: "Configure models and agents",
+      switchNoteAgentHint: "The selected agent will handle subsequent edits to this infographic.",
+      optionUnavailable: "Unavailable",
+
+      switch: "Switch AI",
+      newAgentThread: "Switching to another agent starts a new chat. Previous chats remain in history.",
+      noModels: "Configure AI models in Settings.",
+      switchUnavailable: "Agent unavailable. Check its connection in Settings.",
+
       title: "Agent mode",
       description: "Use the built-in Agent, or connect to an Agent (ACP) running on this machine.",
       localDisabled: "Requires the desktop app.",
diff --git a/packages/shared/src/i18n/ja.ts b/packages/shared/src/i18n/ja.ts
index 90707877..55317453 100644
--- a/packages/shared/src/i18n/ja.ts
+++ b/packages/shared/src/i18n/ja.ts
@@ -1487,6 +1487,15 @@ export const ja = {
       imageSaveFailed: "画像を端末に保存できませんでした。今すぐダウンロードしてください。ページを閉じると失われる可能性があります。",
     },
     agentSource: {
+      configure: "モデルと Agent を設定",
+      switchNoteAgentHint: "選択した Agent が、このインフォグラフィックの次の編集を処理します。",
+      optionUnavailable: "利用不可",
+
+      switch: "AI を切り替え",
+      newAgentThread: "外部 Agent への切り替えは新しい会話を開始します。以前の会話は履歴に残ります。",
+      noModels: "設定で AI モデルを構成してください。",
+      switchUnavailable: "Agent は利用できません。設定で接続を確認してください。",
+
       title: "エージェントの動作モード",
       description: "内蔵 Agent を使用するか、このマシンで動作する Agent (ACP) に接続します。",
       localDisabled: "デスクトップアプリが必要です。",
diff --git a/packages/shared/src/i18n/pl.ts b/packages/shared/src/i18n/pl.ts
index e98624dc..6e5adbd3 100644
--- a/packages/shared/src/i18n/pl.ts
+++ b/packages/shared/src/i18n/pl.ts
@@ -1487,6 +1487,15 @@ export const pl = {
       imageSaveFailed: "Nie udało się zapisać obrazu lokalnie. Pobierz go teraz — może zostać utracony po zamknięciu tej strony.",
     },
     agentSource: {
+      configure: "Konfiguruj modele i agentów",
+      switchNoteAgentHint: "Wybrany agent obsłuży kolejne zmiany tej infografiki.",
+      optionUnavailable: "Niedostępny",
+
+      switch: "Zmień AI",
+      newAgentThread: "Zmiana na zewnętrznego agenta rozpoczyna nową rozmowę. Poprzednie rozmowy pozostają w historii.",
+      noModels: "Skonfiguruj modele AI w ustawieniach.",
+      switchUnavailable: "Agent jest niedostępny. Sprawdź połączenie w ustawieniach.",
+
       title: "Tryb agenta",
       description: "Użyj wbudowanego agenta lub połącz się z agentem (ACP) działającym na tym komputerze.",
       localDisabled: "Wymaga aplikacji desktopowej.",
diff --git a/packages/shared/src/i18n/zh-CN.ts b/packages/shared/src/i18n/zh-CN.ts
index fa40948d..727429aa 100644
--- a/packages/shared/src/i18n/zh-CN.ts
+++ b/packages/shared/src/i18n/zh-CN.ts
@@ -1487,6 +1487,15 @@ export const zhCN = {
       imageSaveFailed: "图片暂时无法保存到本机。请先下载图片，关闭页面后可能无法找回。",
     },
     agentSource: {
+      configure: "配置模型与 Agent",
+      switchNoteAgentHint: "切换后由所选 Agent 继续处理当前信息图。",
+      optionUnavailable: "不可用",
+
+      switch: "切换 AI",
+      newAgentThread: "切换外部 Agent 会开启新对话，原对话保留在历史中。",
+      noModels: "请在设置中配置 AI 模型。",
+      switchUnavailable: "Agent 暂不可用，请在设置中检查连接。",
+
       title: "Agent 运行模式",
       description: "使用应用内置 Agent，或连接本机运行的 Agent (ACP)。",
       localDisabled: "仅支持桌面客户端。",