From a71222607e36d1a6efde856d7996a9e88f0b3856 Mon Sep 17 00:00:00 2001
From: Xubin Ren <52506698+Re-bin@users.noreply.github.com>
Date: Thu, 4 Jun 2026 12:23:57 +0800
Subject: [PATCH] feat(webui): polish desktop chat experience

---
 webui/src/App.tsx                             | 189 ++++-
 webui/src/components/CodeBlock.tsx            | 187 ++++-
 webui/src/components/FilePreviewPanel.tsx     | 289 +++++++
 webui/src/components/FileReferenceChip.tsx    |  63 +-
 webui/src/components/MarkdownText.tsx         |  11 +-
 webui/src/components/MarkdownTextRenderer.tsx |  50 +-
 webui/src/components/MessageBubble.tsx        |  19 +-
 .../src/components/settings/SettingsView.tsx  | 707 +++++++++++++-----
 .../thread/AgentActivityCluster.tsx           |  19 +-
 webui/src/components/thread/PromptRail.tsx    |  68 +-
 .../src/components/thread/ThreadComposer.tsx  |  71 +-
 webui/src/components/thread/ThreadHeader.tsx  |   9 +-
 .../src/components/thread/ThreadMessages.tsx  |  15 +-
 webui/src/components/thread/ThreadShell.tsx   | 219 +++++-
 .../src/components/thread/ThreadViewport.tsx  |   3 +
 .../components/thread/WorkspaceControls.tsx   |   4 +-
 .../thread/activity/FileEditRow.tsx           |  24 +-
 .../thread/activity/ReasoningRow.tsx          |   3 +
 webui/src/globals.css                         |  12 +-
 webui/src/hooks/useNanobotStream.ts           | 155 +++-
 webui/src/i18n/locales/en/common.json         |  39 +
 webui/src/i18n/locales/es/common.json         |  39 +
 webui/src/i18n/locales/fr/common.json         |  39 +
 webui/src/i18n/locales/id/common.json         |  39 +
 webui/src/i18n/locales/ja/common.json         |  39 +
 webui/src/i18n/locales/ko/common.json         |  39 +
 webui/src/i18n/locales/vi/common.json         |  39 +
 webui/src/i18n/locales/zh-CN/common.json      |  39 +
 webui/src/i18n/locales/zh-TW/common.json      |  39 +
 webui/src/lib/activity-timeline.ts            |  79 +-
 webui/src/lib/api.ts                          |  29 +
 webui/src/lib/nanobot-client.ts               |   2 +
 webui/src/lib/types.ts                        |  88 ++-
 webui/src/tests/api.test.ts                   |  25 +
 webui/src/tests/app-layout.test.tsx           |  56 +-
 webui/src/tests/code-block.test.tsx           |  19 +
 .../src/tests/markdown-text-renderer.test.tsx |  41 +-
 webui/src/tests/nanobot-client.test.ts        |  18 +
 webui/src/tests/settings-view.test.tsx        | 325 +++++++-
 webui/src/tests/thread-messages.test.tsx      | 183 ++++-
 webui/src/tests/thread-shell.test.tsx         |  79 +-
 webui/src/tests/thread-viewport.test.tsx      |  36 +
 webui/src/tests/useNanobotStream.test.tsx     |   7 +-
 43 files changed, 3021 insertions(+), 434 deletions(-)
 create mode 100644 webui/src/components/FilePreviewPanel.tsx

diff --git a/webui/src/App.tsx b/webui/src/App.tsx
index 8fa428a7b..4a104838d 100644
--- a/webui/src/App.tsx
+++ b/webui/src/App.tsx
@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { Menu, Moon, Sun } from "lucide-react";
+import { Moon, PanelLeft, Sun } from "lucide-react";
 import { useTranslation } from "react-i18next";
 import { DeleteConfirm } from "@/components/DeleteConfirm";
 import { RenameChatDialog } from "@/components/RenameChatDialog";
@@ -264,11 +264,17 @@ function normalizeWorkspaceScope(scope: WorkspaceScopePayload): WorkspaceScopePa
 
 function HostChrome({
   onToggleSidebar,
+  onSidebarPreviewEnter,
+  onSidebarPreviewLeave,
+  sidebarOpen = true,
   theme,
   onToggleTheme,
   showThemeButton = true,
 }: {
   onToggleSidebar?: () => void;
+  onSidebarPreviewEnter?: () => void;
+  onSidebarPreviewLeave?: () => void;
+  sidebarOpen?: boolean;
   theme: "light" | "dark";
   onToggleTheme: () => void;
   showThemeButton?: boolean;
@@ -276,21 +282,24 @@ function HostChrome({
   const { t } = useTranslation();
 
   return (
-    <header className="host-drag-region pointer-events-none absolute inset-x-0 top-0 z-40 flex h-11 items-start justify-between bg-transparent px-3 pt-2 text-foreground/90">
-      <div className="flex min-w-[8rem] items-center">
-        {onToggleSidebar ? (
-          <Button
-            type="button"
-            variant="ghost"
-            size="icon"
-            aria-label={t("thread.header.toggleSidebar")}
-            onClick={onToggleSidebar}
-            className="host-no-drag pointer-events-auto ml-[88px] h-8 w-8 rounded-xl text-muted-foreground/85 hover:bg-accent/40 hover:text-foreground"
-          >
-            <Menu className="h-4 w-4" />
-          </Button>
-        ) : null}
-      </div>
+    <header className="host-drag-region pointer-events-none absolute inset-x-0 top-0 z-40 h-11 bg-transparent text-foreground/90">
+      {onToggleSidebar ? (
+        <Button
+          type="button"
+          variant="ghost"
+          size="icon"
+          aria-label={t("thread.header.toggleSidebar")}
+          data-testid="host-sidebar-toggle"
+          onClick={onToggleSidebar}
+          onFocus={!sidebarOpen ? onSidebarPreviewEnter : undefined}
+          onBlur={!sidebarOpen ? onSidebarPreviewLeave : undefined}
+          onMouseEnter={!sidebarOpen ? onSidebarPreviewEnter : undefined}
+          onMouseLeave={!sidebarOpen ? onSidebarPreviewLeave : undefined}
+          className="host-no-drag pointer-events-auto absolute left-[88px] top-[8px] h-7 w-7 rounded-lg bg-transparent text-muted-foreground/85 shadow-none hover:bg-transparent hover:text-foreground"
+        >
+          <PanelLeft className="h-[15px] w-[15px]" strokeWidth={1.75} />
+        </Button>
+      ) : null}
       {showThemeButton ? (
         <Button
           type="button"
@@ -298,7 +307,7 @@ function HostChrome({
           size="icon"
           aria-label={t("thread.header.toggleTheme")}
           onClick={onToggleTheme}
-          className="host-no-drag pointer-events-auto h-8 w-8 rounded-full text-muted-foreground/85 hover:bg-accent/40 hover:text-foreground"
+          className="host-no-drag pointer-events-auto absolute right-3 top-2 h-8 w-8 rounded-full text-muted-foreground/85 hover:bg-accent/40 hover:text-foreground"
         >
           {theme === "dark" ? (
             <Sun className="h-4 w-4" />
@@ -307,7 +316,7 @@ function HostChrome({
           )}
         </Button>
       ) : (
-        <div aria-hidden className="host-no-drag pointer-events-none h-8 w-8" />
+        null
       )}
     </header>
   );
@@ -532,6 +541,7 @@ function Shell({
     useState<SettingsSectionKey>(initialRouteRef.current.settingsSection);
   const [hostSidebarOpen, setHostSidebarOpen] =
     useState<boolean>(readSidebarOpen);
+  const [hostSidebarPreviewOpen, setHostSidebarPreviewOpen] = useState(false);
   const [mobileSidebarOpen, setMobileSidebarOpen] = useState(false);
   const [sessionSearchOpen, setSessionSearchOpen] = useState(false);
   const [pendingDelete, setPendingDelete] = useState<{
@@ -560,6 +570,11 @@ function Shell({
     useState<Record<string, WorkspaceScopePayload>>({});
   const runningChatIdsRef = useRef<Set<string>>(new Set());
   const activeChatIdRef = useRef<string | null>(null);
+  const hostSidebarPreviewCloseTimerRef = useRef<number | null>(null);
+  const effectiveRuntimeSurface =
+    settingsSnapshot?.surface ?? settingsSnapshot?.runtime_surface ?? runtimeSurface;
+  const showHostChrome = effectiveRuntimeSurface === "native";
+  const showMainSidebar = view !== "settings";
 
   const navigate = useCallback(
     (route: ShellRoute, options?: { replace?: boolean }) => {
@@ -745,13 +760,74 @@ function Shell({
     });
   }, [client, loading, sessions]);
 
-  const closeHostSidebar = useCallback(() => {
-    setHostSidebarOpen(false);
+  const clearHostSidebarPreviewCloseTimer = useCallback(() => {
+    if (hostSidebarPreviewCloseTimerRef.current === null) return;
+    window.clearTimeout(hostSidebarPreviewCloseTimerRef.current);
+    hostSidebarPreviewCloseTimerRef.current = null;
   }, []);
 
+  const closeHostSidebarPreview = useCallback(() => {
+    clearHostSidebarPreviewCloseTimer();
+    setHostSidebarPreviewOpen(false);
+  }, [clearHostSidebarPreviewCloseTimer]);
+
+  const openHostSidebarPreview = useCallback(() => {
+    if (!showHostChrome || !showMainSidebar || hostSidebarOpen) return;
+    clearHostSidebarPreviewCloseTimer();
+    setHostSidebarPreviewOpen(true);
+  }, [
+    clearHostSidebarPreviewCloseTimer,
+    hostSidebarOpen,
+    showHostChrome,
+    showMainSidebar,
+  ]);
+
+  const scheduleHostSidebarPreviewClose = useCallback(() => {
+    clearHostSidebarPreviewCloseTimer();
+    if (!showHostChrome || !showMainSidebar || hostSidebarOpen) {
+      setHostSidebarPreviewOpen(false);
+      return;
+    }
+    hostSidebarPreviewCloseTimerRef.current = window.setTimeout(() => {
+      setHostSidebarPreviewOpen(false);
+      hostSidebarPreviewCloseTimerRef.current = null;
+    }, 160);
+  }, [
+    clearHostSidebarPreviewCloseTimer,
+    hostSidebarOpen,
+    showHostChrome,
+    showMainSidebar,
+  ]);
+
+  useEffect(() => {
+    return () => clearHostSidebarPreviewCloseTimer();
+  }, [clearHostSidebarPreviewCloseTimer]);
+
+  useEffect(() => {
+    if (!showHostChrome || !showMainSidebar || hostSidebarOpen) {
+      closeHostSidebarPreview();
+    }
+  }, [
+    closeHostSidebarPreview,
+    hostSidebarOpen,
+    showHostChrome,
+    showMainSidebar,
+  ]);
+
+  const closeHostSidebar = useCallback(() => {
+    closeHostSidebarPreview();
+    setHostSidebarOpen(false);
+  }, [closeHostSidebarPreview]);
+
   const openHostSidebar = useCallback(() => {
+    closeHostSidebarPreview();
     setHostSidebarOpen(true);
-  }, []);
+  }, [closeHostSidebarPreview]);
+
+  const toggleHostSidebar = useCallback(() => {
+    closeHostSidebarPreview();
+    setHostSidebarOpen((v) => !v);
+  }, [closeHostSidebarPreview]);
 
   const closeMobileSidebar = useCallback(() => {
     setMobileSidebarOpen(false);
@@ -762,11 +838,12 @@ function Shell({
       typeof window !== "undefined" &&
       window.matchMedia("(min-width: 1024px)").matches;
     if (isNativeHost) {
+      closeHostSidebarPreview();
       setHostSidebarOpen((v) => !v);
     } else {
       setMobileSidebarOpen((v) => !v);
     }
-  }, []);
+  }, [closeHostSidebarPreview]);
 
   const applyWorkspaceScope = useCallback(
     (scope: WorkspaceScopePayload) => {
@@ -1041,6 +1118,10 @@ function Shell({
     setMobileSidebarOpen(false);
   }, [activeKey, navigate]);
 
+  const onOpenModelSettings = useCallback(() => {
+    onOpenSettings("models");
+  }, [onOpenSettings]);
+
   const onOpenApps = useCallback(() => {
     setSessionSearchOpen(false);
     navigate({ view: "apps", activeKey, settingsSection: "apps" });
@@ -1238,11 +1319,13 @@ function Shell({
     archivedCount: sidebarState.archived_keys.length,
     defaultWorkspacePath: workspaces?.default_scope.project_path ?? null,
   };
-  const effectiveRuntimeSurface =
-    settingsSnapshot?.surface ?? settingsSnapshot?.runtime_surface ?? runtimeSurface;
-  const isNativeHostSetupSurface = effectiveRuntimeSurface === "native";
-  const showHostChrome = isNativeHostSetupSurface;
-  const showMainSidebar = view !== "settings";
+  const hostSidebarCollapsed = showHostChrome && !hostSidebarOpen;
+  const showHostSidebarPreview =
+    showMainSidebar && hostSidebarCollapsed && hostSidebarPreviewOpen;
+  const hostSidebarFlowWidth = showHostChrome
+    ? (hostSidebarOpen ? SIDEBAR_WIDTH : 0)
+    : (hostSidebarOpen ? SIDEBAR_WIDTH : SIDEBAR_RAIL_WIDTH);
+  const renderHostSidebarFlowContent = !showHostChrome || hostSidebarOpen;
 
   useEffect(() => {
     document.documentElement.classList.toggle("native-host", showHostChrome);
@@ -1261,7 +1344,10 @@ function Shell({
       >
         {showHostChrome ? (
           <HostChrome
-            onToggleSidebar={showMainSidebar ? toggleSidebar : undefined}
+            onToggleSidebar={showMainSidebar ? toggleHostSidebar : undefined}
+            onSidebarPreviewEnter={openHostSidebarPreview}
+            onSidebarPreviewLeave={scheduleHostSidebarPreviewClose}
+            sidebarOpen={hostSidebarOpen}
             theme={theme}
             onToggleTheme={toggle}
           />
@@ -1274,25 +1360,47 @@ function Shell({
           {/* Host sidebar: in normal flow, so the thread area width stays honest. */}
           {showMainSidebar ? (
             <aside
+              data-testid="host-sidebar-flow"
               className={cn(
                 "relative z-20 hidden shrink-0 overflow-hidden lg:block",
                 "transition-[width] duration-300 ease-out",
               )}
               style={{
-                width: hostSidebarOpen ? SIDEBAR_WIDTH : SIDEBAR_RAIL_WIDTH,
+                width: hostSidebarFlowWidth,
               }}
             >
-              <div
-                className={cn(
-                  "absolute inset-y-0 left-0 h-full w-full overflow-hidden",
-                  showHostChrome
-                    ? "host-sidebar-glass"
-                    : "bg-sidebar shadow-inner-right",
-                )}
-              >
+              {renderHostSidebarFlowContent ? (
+                <div
+                  className={cn(
+                    "absolute inset-y-0 left-0 h-full w-full overflow-hidden",
+                    showHostChrome
+                      ? "host-sidebar-glass"
+                      : "bg-sidebar shadow-inner-right",
+                  )}
+                >
+                  <Sidebar
+                    {...sidebarProps}
+                    collapsed={!showHostChrome && !hostSidebarOpen}
+                    hostChromeInset={showHostChrome}
+                    onCollapse={closeHostSidebar}
+                    onExpand={openHostSidebar}
+                  />
+                </div>
+              ) : null}
+            </aside>
+          ) : null}
+
+          {showHostSidebarPreview ? (
+            <aside
+              data-testid="host-sidebar-preview"
+              className="absolute inset-y-0 left-0 z-30 hidden overflow-hidden lg:block animate-in fade-in-0 slide-in-from-left-2 duration-150"
+              style={{ width: SIDEBAR_WIDTH }}
+              onMouseEnter={openHostSidebarPreview}
+              onMouseLeave={scheduleHostSidebarPreviewClose}
+            >
+              <div className="h-full w-full overflow-hidden host-sidebar-glass shadow-2xl">
                 <Sidebar
                   {...sidebarProps}
-                  collapsed={!hostSidebarOpen}
                   hostChromeInset={showHostChrome}
                   onCollapse={closeHostSidebar}
                   onExpand={openHostSidebar}
@@ -1335,7 +1443,7 @@ function Shell({
         <main
           className={cn(
             "relative flex h-full min-w-0 flex-1 flex-col overflow-hidden bg-background",
-            showHostChrome && "border-l border-border/55",
+            showHostChrome && hostSidebarOpen && "border-l border-border/55",
           )}
         >
             <div
@@ -1354,6 +1462,7 @@ function Shell({
                 theme={theme}
                 onToggleTheme={toggle}
                 hideSidebarToggleForHostChrome
+                hostChromeTitleInset={hostSidebarCollapsed}
                 hideThemeButton={showHostChrome}
                 hideHeader={false}
                 workspaceScope={activeWorkspaceScope}
@@ -1363,6 +1472,7 @@ function Shell({
                 workspaceError={workspaceError}
                 onWorkspaceScopeChange={applyWorkspaceScope}
                 settingsSnapshot={settingsSnapshot}
+                onOpenModelSettings={onOpenModelSettings}
               />
             </div>
             {view !== "chat" && (
@@ -1370,6 +1480,7 @@ function Shell({
                 <SettingsView
                   theme={theme}
                   initialSection={settingsInitialSection}
+                  initialSettings={settingsSnapshot}
                   showSidebar={view === "settings"}
                   onToggleTheme={toggle}
                   onBackToChat={onBackToChat}
diff --git a/webui/src/components/CodeBlock.tsx b/webui/src/components/CodeBlock.tsx
index 52d274c00..289726960 100644
--- a/webui/src/components/CodeBlock.tsx
+++ b/webui/src/components/CodeBlock.tsx
@@ -9,15 +9,33 @@ interface CodeBlockProps {
   language?: string;
   code: string;
   className?: string;
+  chrome?: "default" | "none";
   highlight?: boolean;
+  showLineNumbers?: boolean;
+  wrapLongLines?: boolean;
 }
 
 interface HighlightedCodeProps {
   language?: string;
   code: string;
   isDark: boolean;
+  chrome: "default" | "none";
+  showLineNumbers: boolean;
+  wrapLongLines: boolean;
 }
 
+const CODE_FONT_STACK = [
+  '"JetBrains Mono"',
+  '"SFMono-Regular"',
+  '"SF Mono"',
+  '"Fira Code"',
+  '"Cascadia Code"',
+  '"Source Code Pro"',
+  "Menlo",
+  "Consolas",
+  "monospace",
+].join(", ");
+
 const LazyHighlightedCode = lazy(async () => {
   const [
     { default: SyntaxHighlighter },
@@ -30,19 +48,56 @@ const LazyHighlightedCode = lazy(async () => {
   ]);
 
   return {
-    default({ language, code, isDark }: HighlightedCodeProps) {
+    default({
+      language,
+      code,
+      isDark,
+      chrome,
+      showLineNumbers,
+      wrapLongLines,
+    }: HighlightedCodeProps) {
+      const theme = isDark ? oneDark : oneLight;
+      const transparentTheme = chrome === "none" ? {
+        ...theme,
+        'pre[class*="language-"]': {
+          ...theme['pre[class*="language-"]'],
+          background: "transparent",
+        },
+        'code[class*="language-"]': {
+          ...theme['code[class*="language-"]'],
+          background: "transparent",
+        },
+      } : theme;
+
       return (
         <SyntaxHighlighter
           language={language || "text"}
-          style={isDark ? oneDark : oneLight}
+          style={transparentTheme}
           customStyle={{
+            background: chrome === "none" ? "transparent" : undefined,
             margin: 0,
-            padding: "1rem",
-            fontSize: "0.875rem",
-            lineHeight: 1.6,
+            padding: chrome === "none" ? "0.75rem 1rem" : "1rem",
+            fontFamily: CODE_FONT_STACK,
+            fontSize: chrome === "none" ? "13px" : "0.875rem",
+            lineHeight: chrome === "none" ? 1.55 : 1.6,
+            tabSize: 2,
+          }}
+          codeTagProps={{
+            style: chrome === "none" ? {
+              background: "transparent",
+              fontFamily: CODE_FONT_STACK,
+            } : undefined,
+          }}
+          lineNumberStyle={{
+            minWidth: "2.6em",
+            paddingRight: "1.15rem",
+            color: isDark ? "rgba(212, 212, 216, 0.45)" : "rgba(63, 63, 70, 0.68)",
+            fontFamily: CODE_FONT_STACK,
+            userSelect: "none",
           }}
           PreTag="pre"
-          wrapLongLines
+          showLineNumbers={showLineNumbers}
+          wrapLongLines={wrapLongLines}
         >
           {code}
         </SyntaxHighlighter>
@@ -51,13 +106,39 @@ const LazyHighlightedCode = lazy(async () => {
   };
 });
 
-function PlainCodeFallback({ code }: { code: string }) {
+function PlainCodeFallback({
+  code,
+  chrome,
+  showLineNumbers,
+}: {
+  code: string;
+  chrome: "default" | "none";
+  showLineNumbers: boolean;
+}) {
+  const lines = code.split("\n");
   return (
     <pre
-      className="m-0 overflow-x-auto whitespace-pre-wrap bg-background p-4 font-mono text-sm leading-[1.6] text-foreground/90"
+      className={cn(
+        "m-0 overflow-x-auto p-4 font-mono text-sm leading-[1.6] text-foreground/90",
+        showLineNumbers ? "whitespace-pre" : "whitespace-pre-wrap",
+        chrome === "default" ? "bg-background" : "bg-transparent",
+        chrome === "none" && "p-3 text-[13px] leading-[1.55]",
+      )}
       data-testid="plain-code-fallback"
     >
-      <code className="text-inherit">{code}</code>
+      <code className="text-inherit">
+        {showLineNumbers ? (
+          lines.map((line, index) => (
+            <span key={index} className="flex min-w-max">
+              <span className="w-10 shrink-0 select-none pr-4 text-right text-muted-foreground/60">
+                {index + 1}
+              </span>
+              <span className="whitespace-pre">{line || " "}</span>
+              {index < lines.length - 1 ? "\n" : null}
+            </span>
+          ))
+        ) : code}
+      </code>
     </pre>
   );
 }
@@ -66,11 +147,15 @@ export function CodeBlock({
   language,
   code,
   className,
+  chrome = "default",
   highlight = true,
+  showLineNumbers = false,
+  wrapLongLines = true,
 }: CodeBlockProps) {
   const { t } = useTranslation();
   const [copied, setCopied] = useState(false);
   const isDark = useThemeValue() === "dark";
+  const hasChrome = chrome === "default";
 
   const onCopy = useCallback(() => {
     if (!navigator.clipboard) return;
@@ -83,47 +168,69 @@ export function CodeBlock({
   return (
     <div
       className={cn(
-        "overflow-hidden rounded-lg border",
-        isDark ? "border-white/10" : "border-black/10",
+        "overflow-hidden",
+        hasChrome && "rounded-lg border",
+        hasChrome && (isDark ? "border-white/10" : "border-black/10"),
         className,
       )}
     >
-      <div
-        className={cn(
-          "flex items-center justify-between px-4 py-1.5 text-xs font-medium",
-          isDark
-            ? "bg-zinc-800 text-zinc-300"
-            : "bg-zinc-100 text-zinc-600",
-        )}
-      >
-        <span className="lowercase font-mono">
-          {language || t("code.fallbackLanguage")}
-        </span>
-        <button
-          type="button"
-          onClick={onCopy}
+      {hasChrome ? (
+        <div
           className={cn(
-            "inline-flex items-center gap-1 rounded px-1.5 py-0.5 font-mono transition-colors",
+            "flex items-center justify-between px-4 py-1.5 text-xs font-medium",
             isDark
-              ? "text-zinc-400 hover:bg-zinc-700 hover:text-zinc-200"
-              : "text-zinc-500 hover:bg-zinc-200 hover:text-zinc-700",
+              ? "bg-zinc-800 text-zinc-300"
+              : "bg-zinc-100 text-zinc-600",
           )}
-          aria-label={t("code.copyAria")}
         >
-          {copied ? (
-            <Check className="h-3.5 w-3.5" />
-          ) : (
-            <Copy className="h-3.5 w-3.5" />
-          )}
-          <span>{copied ? t("code.copied") : t("code.copy")}</span>
-        </button>
-      </div>
+          <span className="lowercase font-mono">
+            {language || t("code.fallbackLanguage")}
+          </span>
+          <button
+            type="button"
+            onClick={onCopy}
+            className={cn(
+              "inline-flex items-center gap-1 rounded px-1.5 py-0.5 font-mono transition-colors",
+              isDark
+                ? "text-zinc-400 hover:bg-zinc-700 hover:text-zinc-200"
+                : "text-zinc-500 hover:bg-zinc-200 hover:text-zinc-700",
+            )}
+            aria-label={t("code.copyAria")}
+          >
+            {copied ? (
+              <Check className="h-3.5 w-3.5" />
+            ) : (
+              <Copy className="h-3.5 w-3.5" />
+            )}
+            <span>{copied ? t("code.copied") : t("code.copy")}</span>
+          </button>
+        </div>
+      ) : null}
       {highlight ? (
-        <Suspense fallback={<PlainCodeFallback code={code} />}>
-          <LazyHighlightedCode language={language} code={code} isDark={isDark} />
+        <Suspense
+          fallback={
+            <PlainCodeFallback
+              code={code}
+              chrome={chrome}
+              showLineNumbers={showLineNumbers}
+            />
+          }
+        >
+          <LazyHighlightedCode
+            language={language}
+            code={code}
+            isDark={isDark}
+            chrome={chrome}
+            showLineNumbers={showLineNumbers}
+            wrapLongLines={wrapLongLines}
+          />
         </Suspense>
       ) : (
-        <PlainCodeFallback code={code} />
+        <PlainCodeFallback
+          code={code}
+          chrome={chrome}
+          showLineNumbers={showLineNumbers}
+        />
       )}
     </div>
   );
diff --git a/webui/src/components/FilePreviewPanel.tsx b/webui/src/components/FilePreviewPanel.tsx
new file mode 100644
index 000000000..3eb935ffd
--- /dev/null
+++ b/webui/src/components/FilePreviewPanel.tsx
@@ -0,0 +1,289 @@
+import { useEffect, useMemo, useState } from "react";
+import type { CSSProperties, PointerEvent as ReactPointerEvent } from "react";
+import { AlertCircle, ChevronRight, FileText, Loader2, X } from "lucide-react";
+import { useTranslation } from "react-i18next";
+
+import { CodeBlock } from "@/components/CodeBlock";
+import {
+  splitFilePath,
+} from "@/components/FileReferenceChip";
+import { ApiError, fetchFilePreview } from "@/lib/api";
+import type { FilePreviewPayload } from "@/lib/types";
+import { cn } from "@/lib/utils";
+
+interface FilePreviewPanelProps {
+  sessionKey: string;
+  path: string;
+  token: string;
+  desktopWidth?: number;
+  isClosing?: boolean;
+  onResizeStart?: (event: ReactPointerEvent<HTMLButtonElement>) => void;
+  onClose: () => void;
+}
+
+type PreviewState =
+  | { status: "loading" }
+  | { status: "error"; message: string }
+  | { status: "ready"; payload: FilePreviewPayload };
+
+function supportsHoverCloseControl(): boolean {
+  if (typeof window === "undefined" || typeof window.matchMedia !== "function") return false;
+  return window.matchMedia("(hover: hover) and (pointer: fine)").matches;
+}
+
+export function FilePreviewPanel({
+  sessionKey,
+  path,
+  token,
+  desktopWidth = 544,
+  isClosing = false,
+  onResizeStart,
+  onClose,
+}: FilePreviewPanelProps) {
+  const { t } = useTranslation();
+  const [state, setState] = useState<PreviewState>({ status: "loading" });
+  const [entered, setEntered] = useState(false);
+  const [supportsHoverClose, setSupportsHoverClose] = useState(supportsHoverCloseControl);
+
+  useEffect(() => {
+    const frame = window.requestAnimationFrame(() => setEntered(true));
+    return () => window.cancelAnimationFrame(frame);
+  }, []);
+
+  useEffect(() => {
+    if (typeof window.matchMedia !== "function") return undefined;
+    const query = window.matchMedia("(hover: hover) and (pointer: fine)");
+    const update = () => setSupportsHoverClose(query.matches);
+    update();
+    if (typeof query.addEventListener === "function") {
+      query.addEventListener("change", update);
+      return () => query.removeEventListener("change", update);
+    }
+    query.addListener(update);
+    return () => query.removeListener(update);
+  }, []);
+
+  useEffect(() => {
+    let cancelled = false;
+    setState({ status: "loading" });
+    fetchFilePreview(token, sessionKey, path)
+      .then((payload) => {
+        if (!cancelled) setState({ status: "ready", payload });
+      })
+      .catch((error: unknown) => {
+        if (cancelled) return;
+        const message = error instanceof ApiError
+          ? (error.status === 404 && /API route not found/i.test(error.message)
+            ? t("filePreview.routeMissing", {
+              defaultValue: "File preview needs the latest gateway. Restart nanobot gateway and try again.",
+            })
+            : error.message)
+          : t("filePreview.failed", { defaultValue: "Could not preview this file." });
+        setState({ status: "error", message });
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [path, sessionKey, t, token]);
+
+  const displayPath = state.status === "ready" ? state.payload.display_path : path;
+  const previewPath = state.status === "ready" ? state.payload.path : displayPath;
+  const normalizedPreviewPath = previewPath.replace(/\\/g, "/");
+  const hasRootPrefix = normalizedPreviewPath.startsWith("/");
+  const { name } = splitFilePath(displayPath);
+  const breadcrumbs = useMemo(
+    () => normalizedPreviewPath.split("/").filter(Boolean),
+    [normalizedPreviewPath],
+  );
+  const compactBreadcrumbs = useMemo(
+    () => (breadcrumbs.length > 2 ? breadcrumbs.slice(-2) : breadcrumbs),
+    [breadcrumbs],
+  );
+  const hasCompactPrefix = breadcrumbs.length > compactBreadcrumbs.length;
+
+  return (
+    <aside
+      aria-label={t("filePreview.aria", { defaultValue: "File preview" })}
+      style={{
+        "--file-preview-width": `${desktopWidth}px`,
+        "--file-preview-slot-width": !entered || isClosing ? "0px" : `${desktopWidth}px`,
+      } as CSSProperties}
+      className={cn(
+        "absolute inset-y-0 right-0 z-30 w-[min(92vw,var(--file-preview-slot-width))] overflow-hidden",
+        "transition-[width] duration-300 ease-out will-change-[width]",
+        "md:relative md:z-auto md:w-[var(--file-preview-slot-width)] md:min-w-0 md:shrink-0",
+        isClosing && "pointer-events-none",
+      )}
+      data-testid="file-preview-panel"
+      data-file-preview-panel
+    >
+      <div
+        className={cn(
+          "absolute inset-y-0 right-0 flex w-[min(92vw,var(--file-preview-width))] flex-col overflow-hidden md:w-[var(--file-preview-width)]",
+          "border-l border-border/70 bg-background shadow-2xl md:shadow-none",
+          "transition-[opacity,transform] duration-300 ease-out will-change-transform",
+          !entered || isClosing ? "translate-x-full opacity-0" : "translate-x-0 opacity-100",
+          "motion-reduce:translate-x-0",
+        )}
+      >
+        {onResizeStart ? (
+          <button
+            type="button"
+            aria-label={t("filePreview.resize", { defaultValue: "Resize file preview" })}
+            className={cn(
+              "group absolute inset-y-0 left-0 z-20 hidden w-3 -translate-x-1/2 cursor-col-resize touch-none md:flex",
+              "items-stretch justify-center focus-visible:outline-none",
+            )}
+            onPointerDown={onResizeStart}
+          >
+            <span
+              aria-hidden
+              className={cn(
+                "h-full w-px bg-foreground/25 opacity-0 transition-opacity",
+                "group-hover:opacity-100 group-focus-visible:bg-ring group-focus-visible:opacity-100",
+              )}
+            />
+          </button>
+        ) : null}
+        <div className="flex min-h-0 flex-1 flex-col">
+          <div className="flex h-12 shrink-0 items-center gap-2 border-b border-border/60 px-3">
+            {supportsHoverClose ? (
+              <div
+                className={cn(
+                  "group inline-flex max-w-full min-w-0 items-center gap-2 rounded-[12px]",
+                  "bg-muted/70 px-2.5 py-1.5 text-sm font-medium",
+                )}
+                title={name || displayPath}
+              >
+                <button
+                  type="button"
+                  onClick={onClose}
+                  className={cn(
+                    "relative inline-flex h-5 w-5 shrink-0 items-center justify-center overflow-hidden rounded-full",
+                    "text-muted-foreground/75 transition-[background-color,color,opacity] duration-150 ease-out",
+                    "group-hover:bg-foreground group-hover:text-background group-hover:opacity-100",
+                    "group-focus-within:bg-foreground group-focus-within:text-background",
+                    "focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring",
+                  )}
+                  aria-label={t("filePreview.close", { defaultValue: "Close file preview" })}
+                >
+                  <FileText
+                    className={cn(
+                      "absolute h-4 w-4 transition-all duration-150 ease-out",
+                      "opacity-100 group-hover:scale-75 group-hover:opacity-0",
+                      "group-focus-within:scale-75 group-focus-within:opacity-0",
+                    )}
+                    aria-hidden
+                  />
+                  <X
+                    className={cn(
+                      "absolute h-3.5 w-3.5 scale-75 opacity-0 transition-all duration-150 ease-out",
+                      "group-hover:scale-100 group-hover:opacity-100",
+                      "group-focus-within:scale-100 group-focus-within:opacity-100",
+                    )}
+                    aria-hidden
+                  />
+                </button>
+                <span className="min-w-0 truncate">{name || displayPath}</span>
+              </div>
+            ) : (
+              <>
+                <button
+                  type="button"
+                  onClick={onClose}
+                  className={cn(
+                    "inline-flex h-10 w-10 shrink-0 items-center justify-center rounded-full",
+                    "text-muted-foreground transition-colors hover:bg-muted hover:text-foreground",
+                    "focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring",
+                  )}
+                  aria-label={t("filePreview.close", { defaultValue: "Close file preview" })}
+                >
+                  <X className="h-5 w-5" aria-hidden />
+                </button>
+                <span className="min-w-0 truncate text-sm font-medium">
+                  {name || displayPath}
+                </span>
+              </>
+            )}
+          </div>
+
+          <div className="flex min-h-0 flex-1 flex-col">
+            <div
+              className={cn(
+                "flex min-h-10 shrink-0 items-center gap-1.5 overflow-hidden",
+                "border-b border-border/45 px-4 text-[13px] text-muted-foreground",
+              )}
+              title={previewPath}
+            >
+              <div className="flex min-w-0 items-center gap-1.5">
+                {hasCompactPrefix ? (
+                  <span className="shrink-0 text-muted-foreground/55">...</span>
+                ) : hasRootPrefix ? (
+                  <span className="shrink-0 text-muted-foreground/55">/</span>
+                ) : null}
+                {compactBreadcrumbs.length > 0 ? (
+                  compactBreadcrumbs.map((part, index) => (
+                    <span key={`${part}-${index}`} className="flex min-w-0 items-center gap-1.5">
+                      {index > 0 || hasCompactPrefix || hasRootPrefix ? (
+                        <ChevronRight
+                          className="h-3 w-3 shrink-0 text-muted-foreground/40"
+                          aria-hidden
+                        />
+                      ) : null}
+                      <span
+                        className={cn(
+                          "min-w-0 truncate",
+                          index === compactBreadcrumbs.length - 1
+                            ? "font-medium text-foreground"
+                            : "max-w-[42vw] shrink text-muted-foreground/76",
+                        )}
+                      >
+                        {part}
+                      </span>
+                    </span>
+                  ))
+                ) : (
+                  <span className="truncate">{previewPath}</span>
+                )}
+              </div>
+            </div>
+
+            <div className="min-h-0 flex-1 overflow-auto">
+              {state.status === "loading" ? (
+                <div className="flex h-full items-center justify-center gap-2 text-sm text-muted-foreground">
+                  <Loader2 className="h-4 w-4 animate-spin" aria-hidden />
+                  {t("filePreview.loading", { defaultValue: "Loading preview..." })}
+                </div>
+              ) : state.status === "error" ? (
+                <div className="flex h-full items-center justify-center px-8 text-center text-sm text-muted-foreground">
+                  <div className="max-w-sm">
+                    <AlertCircle className="mx-auto mb-3 h-5 w-5 text-muted-foreground/70" aria-hidden />
+                    <p>{state.message}</p>
+                  </div>
+                </div>
+              ) : (
+                <div className="min-h-full">
+                  {state.payload.truncated ? (
+                    <div className="mx-4 mt-3 rounded-md border border-amber-500/25 bg-amber-500/10 px-3 py-2 text-xs text-amber-700 dark:text-amber-200">
+                      {t("filePreview.truncated", {
+                        defaultValue: "Preview is truncated because this file is large.",
+                      })}
+                    </div>
+                  ) : null}
+                  <CodeBlock
+                    language={state.payload.language}
+                    code={state.payload.content}
+                    chrome="none"
+                    showLineNumbers
+                    wrapLongLines={false}
+                    className="min-h-full"
+                  />
+                </div>
+              )}
+          </div>
+        </div>
+      </div>
+      </div>
+    </aside>
+  );
+}
diff --git a/webui/src/components/FileReferenceChip.tsx b/webui/src/components/FileReferenceChip.tsx
index 73bd76bf2..dac9baa7f 100644
--- a/webui/src/components/FileReferenceChip.tsx
+++ b/webui/src/components/FileReferenceChip.tsx
@@ -1,3 +1,5 @@
+import type { KeyboardEvent, MouseEvent } from "react";
+
 import {
   Tooltip,
   TooltipContent,
@@ -6,10 +8,11 @@ import {
 } from "@/components/ui/tooltip";
 import { cn } from "@/lib/utils";
 
-type FileReferenceKind =
+export type FileReferenceKind =
   | "default"
   | "css"
   | "html"
+  | "javascript"
   | "json"
   | "markdown"
   | "notebook"
@@ -24,6 +27,8 @@ interface FileReferenceChipProps {
   active?: boolean;
   className?: string;
   textClassName?: string;
+  previewPath?: string;
+  onOpen?: (path: string) => void;
   testId?: string;
 }
 
@@ -34,12 +39,26 @@ export function FileReferenceChip({
   active = false,
   className,
   textClassName,
+  previewPath,
+  onOpen,
   testId = "inline-file-path",
 }: FileReferenceChipProps) {
   const { directory, name } = splitFilePath(path);
   const kind = fileKindForPath(path);
   const displayText = display === "path" ? path.replace(/\\/g, "/") : name;
   const fullPath = tooltipPath || path;
+  const targetPath = previewPath || tooltipPath || path;
+  const interactive = Boolean(onOpen);
+  const openPreview = (event: MouseEvent | KeyboardEvent) => {
+    if (!onOpen) return;
+    event.preventDefault();
+    event.stopPropagation();
+    onOpen(targetPath);
+  };
+  const onKeyDown = (event: KeyboardEvent) => {
+    if (event.key !== "Enter" && event.key !== " ") return;
+    openPreview(event);
+  };
   return (
     <TooltipProvider delayDuration={500} skipDelayDuration={100}>
       <Tooltip>
@@ -50,10 +69,18 @@ export function FileReferenceChip({
             <span
               data-testid={testId}
               aria-label={fullPath}
+              role={interactive ? "button" : undefined}
+              tabIndex={interactive ? 0 : undefined}
+              onClick={interactive ? openPreview : undefined}
+              onKeyDown={interactive ? onKeyDown : undefined}
               className={cn(
                 "inline-flex max-w-full items-baseline gap-[0.28em] font-medium leading-[inherit]",
                 "text-sky-600 transition-colors hover:text-sky-700",
                 "dark:text-sky-300 dark:hover:text-sky-200",
+                interactive && [
+                  "cursor-pointer rounded-[5px]",
+                  "focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-sky-400/45",
+                ],
               )}
             >
               <FileReferenceIcon kind={kind} />
@@ -110,7 +137,7 @@ export function isLikelyFilePath(value: string): boolean {
   return /\.[a-z0-9][a-z0-9_-]{0,12}$/i.test(name);
 }
 
-function splitFilePath(path: string): { directory: string; name: string } {
+export function splitFilePath(path: string): { directory: string; name: string } {
   const normalized = path.replace(/\\/g, "/");
   const slash = normalized.lastIndexOf("/");
   if (slash < 0) return { directory: "", name: path };
@@ -120,7 +147,7 @@ function splitFilePath(path: string): { directory: string; name: string } {
   };
 }
 
-function fileKindForPath(path: string): FileReferenceKind {
+export function fileKindForPath(path: string): FileReferenceKind {
   const normalized = path.toLowerCase();
   const name = normalized.split(/[\\/]/).pop() ?? normalized;
   const ext = name.includes(".") ? name.split(".").pop() ?? "" : "";
@@ -134,7 +161,13 @@ function fileKindForPath(path: string): FileReferenceKind {
     case "jsx":
     case "tsx":
       return "react";
+    case "js":
+    case "mjs":
+    case "cjs":
+      return "javascript";
     case "ts":
+    case "mts":
+    case "cts":
       return "typescript";
     case "html":
     case "htm":
@@ -156,7 +189,27 @@ function fileKindForPath(path: string): FileReferenceKind {
   }
 }
 
-function FileReferenceIcon({ kind }: { kind: FileReferenceKind }) {
+export function FileReferenceIcon({ kind }: { kind: FileReferenceKind }) {
+  if (kind === "python") {
+    return (
+      <svg
+        aria-hidden
+        className="h-[1em] w-[1em] shrink-0 translate-y-[0.12em]"
+        viewBox="0 0 24 24"
+      >
+        <path
+          d="M11.9 2.3c-3 0-4.5.8-4.5 2.3v2.1h4.8v.8H5.5C4 7.5 3 8.8 3 10.8v2.1c0 1.8 1.1 3 2.7 3h1.6v-2.3c0-1.7 1.4-3.1 3.1-3.1h4.2c1.3 0 2.3-1 2.3-2.3V4.6c0-1.4-1.5-2.3-4.6-2.3h-.4Z"
+          fill="#3776AB"
+        />
+        <path
+          d="M12.1 21.7c3 0 4.5-.8 4.5-2.3v-2.1h-4.8v-.8h6.7c1.5 0 2.5-1.3 2.5-3.3v-2.1c0-1.8-1.1-3-2.7-3h-1.6v2.3c0 1.7-1.4 3.1-3.1 3.1H9.4c-1.3 0-2.3 1-2.3 2.3v3.6c0 1.4 1.5 2.3 4.6 2.3h.4Z"
+          fill="#FFD43B"
+        />
+        <circle cx="9" cy="5.1" r="0.8" fill="#fff" />
+        <circle cx="15" cy="18.9" r="0.8" fill="#5C3B00" opacity="0.85" />
+      </svg>
+    );
+  }
   if (kind === "react") {
     return (
       <svg
@@ -234,6 +287,8 @@ function fileKindLabel(kind: FileReferenceKind): string {
       return "#";
     case "html":
       return "H";
+    case "javascript":
+      return "JS";
     case "json":
       return "{}";
     case "markdown":
diff --git a/webui/src/components/MarkdownText.tsx b/webui/src/components/MarkdownText.tsx
index bad9801ca..875f53032 100644
--- a/webui/src/components/MarkdownText.tsx
+++ b/webui/src/components/MarkdownText.tsx
@@ -16,6 +16,7 @@ interface MarkdownTextProps {
   children: string;
   className?: string;
   streaming?: boolean;
+  onOpenFilePreview?: (path: string) => void;
 }
 
 const loadMarkdownRenderer = () => import("@/components/MarkdownTextRenderer");
@@ -25,13 +26,19 @@ const MemoizedMarkdownRenderer = memo(function MemoizedMarkdownRenderer({
   source,
   className,
   highlightCode,
+  onOpenFilePreview,
 }: {
   source: string;
   className?: string;
   highlightCode: boolean;
+  onOpenFilePreview?: (path: string) => void;
 }) {
   return (
-    <LazyMarkdownRenderer className={className} highlightCode={highlightCode}>
+    <LazyMarkdownRenderer
+      className={className}
+      highlightCode={highlightCode}
+      onOpenFilePreview={onOpenFilePreview}
+    >
       {source}
     </LazyMarkdownRenderer>
   );
@@ -55,6 +62,7 @@ export function MarkdownText({
   children,
   className,
   streaming = false,
+  onOpenFilePreview,
 }: MarkdownTextProps) {
   const renderedSource = useStreamingMarkdownSource(children, streaming);
   const highlightCode = streaming
@@ -82,6 +90,7 @@ export function MarkdownText({
         source={renderedSource}
         className={className}
         highlightCode={highlightCode}
+        onOpenFilePreview={onOpenFilePreview}
       />
     </Suspense>
   );
diff --git a/webui/src/components/MarkdownTextRenderer.tsx b/webui/src/components/MarkdownTextRenderer.tsx
index 903597c6e..2ce9cfb5f 100644
--- a/webui/src/components/MarkdownTextRenderer.tsx
+++ b/webui/src/components/MarkdownTextRenderer.tsx
@@ -19,6 +19,7 @@ interface MarkdownTextRendererProps {
   children: string;
   className?: string;
   highlightCode?: boolean;
+  onOpenFilePreview?: (path: string) => void;
 }
 
 type MarkdownAstNode = {
@@ -187,6 +188,38 @@ function nodeText(value: ReactNode): string {
     .join("");
 }
 
+function cleanFileReferenceTarget(value: string): string {
+  let target = value.trim();
+  if (!target) return "";
+  try {
+    if (/^file:\/\//i.test(target)) {
+      target = decodeURIComponent(new URL(target).pathname);
+    } else {
+      target = decodeURIComponent(target);
+    }
+  } catch {
+    // Keep the raw value when URL/path decoding is not possible.
+  }
+  target = target.split("?", 1)[0]?.split("#", 1)[0]?.trim() ?? "";
+  if (!/^[A-Za-z]:[\\/]/.test(target)) {
+    target = target.replace(/:\d+(?::\d+)?$/, "");
+  }
+  return target;
+}
+
+function isPreviewableFileTarget(value: string): boolean {
+  if (isLikelyFilePath(value)) return true;
+  if (/^[a-z][a-z0-9+.-]*:\/\//i.test(value)) return false;
+  if (/[\\/]/.test(value)) return false;
+  return /^[^?#]+\.[a-z0-9][a-z0-9_-]{0,12}$/i.test(value);
+}
+
+function fileReferenceFromLink(href: string | undefined): string | null {
+  if (!href || /^https?:\/\//i.test(href) || href.startsWith("#")) return null;
+  const target = cleanFileReferenceTarget(href);
+  return isPreviewableFileTarget(target) ? target : null;
+}
+
 function linkPreviewParts(value: ReactNode): { text: string; href?: string } {
   let text = "";
   let href: string | undefined;
@@ -326,6 +359,7 @@ export default function MarkdownTextRenderer({
   children,
   className,
   highlightCode = true,
+  onOpenFilePreview,
 }: MarkdownTextRendererProps) {
   const components = useMemo<Components>(
     () => ({
@@ -344,7 +378,7 @@ export default function MarkdownTextRenderer({
         }
         const raw = String(kids).replace(/\n$/, "");
         if (isLikelyFilePath(raw)) {
-          return <FileReferenceChip path={raw} />;
+          return <FileReferenceChip path={raw} onOpen={onOpenFilePreview} />;
         }
         /** Plain fenced ``` blocks (no language) & wide one-liners: block monospace, not inline pill. */
         const widePlainBlock = raw.includes("\n") || raw.length > 120;
@@ -405,6 +439,18 @@ export default function MarkdownTextRenderer({
         );
       },
       a({ href, children: markdownChildren, ...props }) {
+        const filePath = fileReferenceFromLink(href);
+        if (filePath) {
+          const label = nodeText(markdownChildren).trim();
+          return (
+            <FileReferenceChip
+              path={label || filePath}
+              tooltipPath={filePath}
+              previewPath={filePath}
+              onOpen={onOpenFilePreview}
+            />
+          );
+        }
         return (
           <a
             href={href}
@@ -495,7 +541,7 @@ export default function MarkdownTextRenderer({
         );
       },
     }),
-    [highlightCode],
+    [highlightCode, onOpenFilePreview],
   );
 
   return (
diff --git a/webui/src/components/MessageBubble.tsx b/webui/src/components/MessageBubble.tsx
index 8e003ca67..5d4f137ae 100644
--- a/webui/src/components/MessageBubble.tsx
+++ b/webui/src/components/MessageBubble.tsx
@@ -33,6 +33,7 @@ interface MessageBubbleProps {
   showAssistantCopyAction?: boolean;
   cliApps?: CliAppInfo[];
   mcpPresets?: McpPresetInfo[];
+  onOpenFilePreview?: (path: string) => void;
 }
 
 /**
@@ -49,6 +50,7 @@ export function MessageBubble({
   showAssistantCopyAction = true,
   cliApps = [],
   mcpPresets = [],
+  onOpenFilePreview,
 }: MessageBubbleProps) {
   const { t } = useTranslation();
   const [copied, setCopied] = useState(false);
@@ -142,13 +144,23 @@ export function MessageBubble({
   return (
     <div className={cn("w-full text-[15px]", baseAnim)} style={{ lineHeight: "var(--cjk-line-height)" }}>
       {hasReasoning ? (
-        <ReasoningBubble text={reasoning} streaming={reasoningStreaming} hasBodyBelow={!empty} />
+        <ReasoningBubble
+          text={reasoning}
+          streaming={reasoningStreaming}
+          hasBodyBelow={!empty}
+          onOpenFilePreview={onOpenFilePreview}
+        />
       ) : null}
       {empty && message.isStreaming && !hasReasoning ? (
         <TypingDots />
       ) : empty && message.isStreaming ? null : (
         <>
-          <MarkdownText streaming={!!message.isStreaming}>{message.content}</MarkdownText>
+          <MarkdownText
+            streaming={!!message.isStreaming}
+            onOpenFilePreview={onOpenFilePreview}
+          >
+            {message.content}
+          </MarkdownText>
           {media.length > 0 ? <MessageMedia media={media} align="left" /> : null}
           {showAssistantFooterRow ? (
             <div className="mt-2 flex min-h-8 flex-wrap items-center gap-x-2 gap-y-1 text-muted-foreground">
@@ -488,6 +500,7 @@ interface ReasoningBubbleProps {
   hasBodyBelow: boolean;
   /** When true, skip the slide-in wrapper (used inside ``AgentActivityCluster``). */
   embeddedInCluster?: boolean;
+  onOpenFilePreview?: (path: string) => void;
 }
 
 /**
@@ -509,6 +522,7 @@ export function ReasoningBubble({
   streaming,
   hasBodyBelow,
   embeddedInCluster = false,
+  onOpenFilePreview,
 }: ReasoningBubbleProps) {
   const { t } = useTranslation();
   const [userToggled, setUserToggled] = useState(false);
@@ -567,6 +581,7 @@ export function ReasoningBubble({
         >
           <MarkdownText
             streaming={streaming}
+            onOpenFilePreview={onOpenFilePreview}
             className={cn(
               "text-[12.5px] italic text-muted-foreground/88",
               "prose-p:my-1.5 prose-li:my-0.5",
diff --git a/webui/src/components/settings/SettingsView.tsx b/webui/src/components/settings/SettingsView.tsx
index 66792e7f0..31d3e3c57 100644
--- a/webui/src/components/settings/SettingsView.tsx
+++ b/webui/src/components/settings/SettingsView.tsx
@@ -13,6 +13,7 @@ import {
   Bot,
   Brain,
   Check,
+  CircleAlert,
   ChevronDown,
   ChevronLeft,
   ChevronRight,
@@ -70,9 +71,16 @@ import {
 } from "@/components/ui/dialog";
 import { Input } from "@/components/ui/input";
 import { Textarea } from "@/components/ui/textarea";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
 import {
   createModelConfiguration,
   fetchSettings,
+  fetchSettingsUsage,
   fetchCliApps,
   fetchMcpPresets,
   fetchProviderModels,
@@ -99,6 +107,7 @@ import {
   providerDisplayLabel,
 } from "@/lib/provider-brand";
 import { cn } from "@/lib/utils";
+import { shortWorkspacePath } from "@/lib/workspace";
 import { useClient } from "@/providers/ClientProvider";
 import type {
   CliAppInfo,
@@ -167,7 +176,6 @@ type ProviderApiType = "auto" | "chat_completions" | "responses";
 type ProviderForm = { apiKey: string; apiBase: string; apiType: ProviderApiType };
 type CustomMcpTransport = "stdio" | "streamableHttp" | "sse";
 
-const NANOBOT_ICON_SRC = "/brand/nanobot_icon.png";
 const CONTEXT_WINDOW_TOKEN_OPTIONS = [65_536, 262_144] as const;
 const DEFERRED_MODEL_LIST_PROVIDERS = new Set([
   "aihubmix",
@@ -265,6 +273,7 @@ const DEFAULT_CUSTOM_MCP_FORM: CustomMcpForm = {
 interface SettingsViewProps {
   theme: "light" | "dark";
   initialSection?: SettingsSectionKey;
+  initialSettings?: SettingsPayload | null;
   showSidebar?: boolean;
   onToggleTheme: () => void;
   onBackToChat: () => void;
@@ -311,9 +320,130 @@ function editableDefaultProvider(payload: SettingsPayload): string {
   return base?.provider ?? payload.agent.provider ?? payload.agent.resolved_provider ?? "";
 }
 
+function settingsProviderRow(
+  payload: SettingsPayload,
+  provider: string | null | undefined,
+): SettingsPayload["providers"][number] | null {
+  if (!provider) return null;
+  return payload.providers.find((row) => row.name === provider) ?? null;
+}
+
+function settingsProviderConfigured(
+  payload: SettingsPayload,
+  provider: string | null | undefined,
+): boolean {
+  const row = settingsProviderRow(payload, provider);
+  if (row) return row.configured;
+  return payload.agent.has_api_key;
+}
+
+const DEFAULT_AGENT_SETTINGS_DRAFT: AgentSettingsDraft = {
+  model: "",
+  provider: "",
+  modelPreset: "default",
+  presetLabel: "Default",
+  contextWindowTokens: 65_536,
+  timezone: "UTC",
+  botName: "nanobot",
+  botIcon: "",
+  toolHintMaxLength: 40,
+};
+
+const DEFAULT_WEB_SEARCH_FORM: WebSearchSettingsUpdate = {
+  provider: "duckduckgo",
+  apiKey: "",
+  baseUrl: "",
+  maxResults: 5,
+  timeout: 30,
+  useJinaReader: true,
+};
+
+const DEFAULT_IMAGE_GENERATION_FORM: ImageGenerationSettingsUpdate = {
+  enabled: false,
+  provider: "openrouter",
+  model: "openai/gpt-5.4-image-2",
+  defaultAspectRatio: "1:1",
+  defaultImageSize: "1K",
+  maxImagesPerTurn: 4,
+};
+
+const DEFAULT_NETWORK_SAFETY_FORM: NetworkSafetySettingsUpdate = {
+  webuiAllowLocalServiceAccess: true,
+  webuiDefaultAccessMode: "default",
+};
+
+function agentDraftFromPayload(payload: SettingsPayload): AgentSettingsDraft {
+  const fallbackDefault = defaultPreset(payload);
+  const activePresetName = modelPresetValue(payload);
+  const activePreset =
+    payload.model_presets.find((preset) => preset.name === activePresetName) ?? fallbackDefault;
+  return {
+    model: activePreset?.model ?? payload.agent.model,
+    provider: activePreset?.is_default
+      ? editableDefaultProvider(payload)
+      : activePreset?.provider ?? editableDefaultProvider(payload),
+    modelPreset: activePresetName,
+    presetLabel: activePreset?.label ?? activePresetName,
+    contextWindowTokens: normalizeContextWindowTokens(
+      activePreset?.context_window_tokens ?? payload.agent.context_window_tokens,
+    ),
+    timezone: payload.agent.timezone,
+    botName: payload.agent.bot_name,
+    botIcon: payload.agent.bot_icon,
+    toolHintMaxLength: payload.agent.tool_hint_max_length,
+  };
+}
+
+function webSearchFormFromPayload(
+  payload: SettingsPayload,
+  previous?: WebSearchSettingsUpdate,
+): WebSearchSettingsUpdate {
+  return {
+    provider: payload.web_search.provider,
+    apiKey: previous?.provider === payload.web_search.provider ? previous.apiKey ?? "" : "",
+    baseUrl: payload.web_search.base_url ?? "",
+    maxResults: payload.web_search.max_results,
+    timeout: payload.web_search.timeout,
+    useJinaReader: payload.web.fetch.use_jina_reader,
+  };
+}
+
+function imageGenerationFormFromPayload(payload: SettingsPayload): ImageGenerationSettingsUpdate {
+  return {
+    enabled: payload.image_generation.enabled,
+    provider: payload.image_generation.provider,
+    model: payload.image_generation.model,
+    defaultAspectRatio: payload.image_generation.default_aspect_ratio,
+    defaultImageSize: payload.image_generation.default_image_size,
+    maxImagesPerTurn: payload.image_generation.max_images_per_turn,
+  };
+}
+
+function networkSafetyFormFromPayload(payload: SettingsPayload): NetworkSafetySettingsUpdate {
+  return {
+    webuiAllowLocalServiceAccess:
+      payload.advanced.webui_allow_local_service_access ??
+      payload.advanced.allow_local_preview_access ??
+      true,
+    webuiDefaultAccessMode: visibleWebuiDefaultAccessMode(
+      payload.advanced.webui_default_access_mode,
+    ),
+  };
+}
+
+function pendingRestartSectionsFromPayload(payload: SettingsPayload): PendingRestartSections {
+  const sections = payload.restart_required_sections ?? [];
+  return {
+    runtime: sections.includes("runtime"),
+    browser: sections.includes("browser"),
+    image: sections.includes("image"),
+  };
+}
+
 export function SettingsView({
   theme,
   initialSection = "overview",
+  initialSettings = null,
   showSidebar = true,
   onToggleTheme,
   onBackToChat,
@@ -328,10 +458,10 @@ export function SettingsView({
 }: SettingsViewProps) {
   const { t } = useTranslation();
   const { token } = useClient();
-  const [settings, setSettings] = useState<SettingsPayload | null>(null);
+  const [settings, setSettings] = useState<SettingsPayload | null>(() => initialSettings);
   const [cliApps, setCliApps] = useState<CliAppsPayload | null>(null);
   const [mcpPresets, setMcpPresets] = useState<McpPresetsPayload | null>(null);
-  const [loading, setLoading] = useState(true);
+  const [loading, setLoading] = useState(() => initialSettings === null);
   const [cliAppsLoading, setCliAppsLoading] = useState(true);
   const [mcpPresetsLoading, setMcpPresetsLoading] = useState(true);
   const [saving, setSaving] = useState(false);
@@ -370,26 +500,18 @@ export function SettingsView({
     EMPTY_PENDING_RESTART_SECTIONS,
   );
   const [localPrefs, setLocalPrefs] = useState<LocalPreferences>(() => readLocalPreferences());
-  const [webSearchForm, setWebSearchForm] = useState<WebSearchSettingsUpdate>({
-    provider: "duckduckgo",
-    apiKey: "",
-    baseUrl: "",
-    maxResults: 5,
-    timeout: 30,
-    useJinaReader: true,
-  });
-  const [imageGenerationForm, setImageGenerationForm] = useState<ImageGenerationSettingsUpdate>({
-    enabled: false,
-    provider: "openrouter",
-    model: "openai/gpt-5.4-image-2",
-    defaultAspectRatio: "1:1",
-    defaultImageSize: "1K",
-    maxImagesPerTurn: 4,
-  });
-  const [networkSafetyForm, setNetworkSafetyForm] = useState<NetworkSafetySettingsUpdate>({
-    webuiAllowLocalServiceAccess: true,
-    webuiDefaultAccessMode: "default",
-  });
+  const [webSearchForm, setWebSearchForm] = useState<WebSearchSettingsUpdate>(() =>
+    initialSettings ? webSearchFormFromPayload(initialSettings) : DEFAULT_WEB_SEARCH_FORM,
+  );
+  const [imageGenerationForm, setImageGenerationForm] = useState<ImageGenerationSettingsUpdate>(
+    () =>
+      initialSettings
+        ? imageGenerationFormFromPayload(initialSettings)
+        : DEFAULT_IMAGE_GENERATION_FORM,
+  );
+  const [networkSafetyForm, setNetworkSafetyForm] = useState<NetworkSafetySettingsUpdate>(() =>
+    initialSettings ? networkSafetyFormFromPayload(initialSettings) : DEFAULT_NETWORK_SAFETY_FORM,
+  );
 
   useEffect(() => {
     setActiveSection(initialSection);
@@ -404,17 +526,9 @@ export function SettingsView({
   );
   const [webSearchKeyVisible, setWebSearchKeyVisible] = useState(false);
   const [webSearchKeyEditing, setWebSearchKeyEditing] = useState(false);
-  const [form, setForm] = useState<AgentSettingsDraft>({
-    model: "",
-    provider: "",
-    modelPreset: "default",
-    presetLabel: "Default",
-    contextWindowTokens: 65_536,
-    timezone: "UTC",
-    botName: "nanobot",
-    botIcon: "",
-    toolHintMaxLength: 40,
-  });
+  const [form, setForm] = useState<AgentSettingsDraft>(() =>
+    initialSettings ? agentDraftFromPayload(initialSettings) : DEFAULT_AGENT_SETTINGS_DRAFT,
+  );
 
   const text = useCallback(
     (key: string, fallback: string, options?: Record<string, unknown>) =>
@@ -423,59 +537,27 @@ export function SettingsView({
   );
 
   const applyPayload = useCallback((payload: SettingsPayload) => {
-    const fallbackDefault = defaultPreset(payload);
-    const activePresetName = modelPresetValue(payload);
-    const activePreset =
-      payload.model_presets.find((preset) => preset.name === activePresetName) ?? fallbackDefault;
     setSettings(payload);
-    setForm({
-      model: activePreset?.model ?? payload.agent.model,
-      provider: activePreset?.is_default
-        ? editableDefaultProvider(payload)
-        : activePreset?.provider ?? editableDefaultProvider(payload),
-      modelPreset: activePresetName,
-      presetLabel: activePreset?.label ?? activePresetName,
-      contextWindowTokens: normalizeContextWindowTokens(
-        activePreset?.context_window_tokens ?? payload.agent.context_window_tokens,
-      ),
-      timezone: payload.agent.timezone,
-      botName: payload.agent.bot_name,
-      botIcon: payload.agent.bot_icon,
-      toolHintMaxLength: payload.agent.tool_hint_max_length,
-    });
-    setWebSearchForm((prev) => ({
-      provider: payload.web_search.provider,
-      apiKey: prev.provider === payload.web_search.provider ? prev.apiKey ?? "" : "",
-      baseUrl: payload.web_search.base_url ?? "",
-      maxResults: payload.web_search.max_results,
-      timeout: payload.web_search.timeout,
-      useJinaReader: payload.web.fetch.use_jina_reader,
-    }));
-    setImageGenerationForm({
-      enabled: payload.image_generation.enabled,
-      provider: payload.image_generation.provider,
-      model: payload.image_generation.model,
-      defaultAspectRatio: payload.image_generation.default_aspect_ratio,
-      defaultImageSize: payload.image_generation.default_image_size,
-      maxImagesPerTurn: payload.image_generation.max_images_per_turn,
-    });
-    setNetworkSafetyForm({
-      webuiAllowLocalServiceAccess: payload.advanced.webui_allow_local_service_access ?? payload.advanced.allow_local_preview_access ?? true,
-      webuiDefaultAccessMode: visibleWebuiDefaultAccessMode(payload.advanced.webui_default_access_mode),
-    });
+    setForm(agentDraftFromPayload(payload));
+    setWebSearchForm((prev) => webSearchFormFromPayload(payload, prev));
+    setImageGenerationForm(imageGenerationFormFromPayload(payload));
+    setNetworkSafetyForm(networkSafetyFormFromPayload(payload));
     if (payload.restart_required_sections) {
-      setPendingRestartSections({
-        runtime: payload.restart_required_sections.includes("runtime"),
-        browser: payload.restart_required_sections.includes("browser"),
-        image: payload.restart_required_sections.includes("image"),
-      });
+      setPendingRestartSections(pendingRestartSectionsFromPayload(payload));
     }
     onSettingsChange?.(payload);
   }, [onSettingsChange]);
 
+  useEffect(() => {
+    if (!initialSettings || settings !== null) return;
+    applyPayload(initialSettings);
+    setLoading(false);
+  }, [applyPayload, initialSettings, settings]);
+
   useEffect(() => {
     let cancelled = false;
-    setLoading(true);
+    const showLoading = settings === null;
+    if (showLoading) setLoading(true);
     fetchSettings(token)
       .then((payload) => {
         if (!cancelled) {
@@ -484,7 +566,7 @@ export function SettingsView({
         }
       })
       .catch((err) => {
-        if (!cancelled) setError((err as Error).message);
+        if (!cancelled && showLoading) setError((err as Error).message);
       })
       .finally(() => {
         if (!cancelled) setLoading(false);
@@ -494,6 +576,34 @@ export function SettingsView({
     };
   }, [applyPayload, token]);
 
+  const hasSettings = settings !== null;
+  useEffect(() => {
+    if (activeSection !== "overview" || !hasSettings) return;
+    let cancelled = false;
+    const refresh = () => {
+      fetchSettingsUsage(token)
+        .then((usage) => {
+          if (cancelled) return;
+          setSettings((current) => (current ? { ...current, usage } : current));
+        })
+        .catch(() => {});
+    };
+    void refresh();
+    const interval = window.setInterval(refresh, 5000);
+    const onFocus = () => refresh();
+    const onVisibilityChange = () => {
+      if (document.visibilityState === "visible") refresh();
+    };
+    window.addEventListener("focus", onFocus);
+    document.addEventListener("visibilitychange", onVisibilityChange);
+    return () => {
+      cancelled = true;
+      window.clearInterval(interval);
+      window.removeEventListener("focus", onFocus);
+      document.removeEventListener("visibilitychange", onVisibilityChange);
+    };
+  }, [activeSection, hasSettings, token]);
+
   useEffect(() => {
     if (activeSection !== "apps") return;
     let cancelled = false;
@@ -1135,8 +1245,6 @@ export function SettingsView({
           <OverviewSettings
             settings={settings}
             requiresRestart={hasPendingRestart}
-            onRestart={restartViaSettingsSurface}
-            isRestarting={isRestarting || hostEngineApplying}
             showBrandLogos={localPrefs.brandLogos}
             onSelectSection={selectSection}
           />
@@ -1354,10 +1462,10 @@ export function SettingsView({
           )}
         >
           <div className="mb-7">
-            <p className="mb-2 text-[13px] font-medium text-muted-foreground">
+            <p className="mb-2 text-[12px] font-normal text-muted-foreground">
               {t("settings.sidebar.title")}
             </p>
-            <h1 className="text-[28px] font-semibold leading-tight tracking-[-0.02em] text-foreground sm:text-[34px]">
+            <h1 className="text-[24px] font-normal leading-tight tracking-normal text-foreground sm:text-[28px]">
               {text(`settings.nav.${activeSection}`, titleForSection(activeSection))}
             </h1>
           </div>
@@ -1437,7 +1545,7 @@ function SettingsSidebar({
         {t("settings.backToChat")}
       </button>
       <div className="mb-3 px-1 md:mb-4 md:px-2">
-        <h2 className="text-[21px] font-semibold tracking-[-0.02em] text-foreground">
+        <h2 className="text-[18px] font-normal tracking-normal text-foreground">
           {t("settings.sidebar.title")}
         </h2>
       </div>
@@ -1488,15 +1596,11 @@ function SettingsSidebar({
 function OverviewSettings({
   settings,
   requiresRestart,
-  onRestart,
-  isRestarting,
   onSelectSection,
   showBrandLogos,
 }: {
   settings: SettingsPayload;
   requiresRestart: boolean;
-  onRestart?: () => void;
-  isRestarting?: boolean;
   onSelectSection: (section: SettingsSectionKey) => void;
   showBrandLogos: boolean;
 }) {
@@ -1504,6 +1608,16 @@ function OverviewSettings({
   const tx = (key: string, fallback: string) => t(key, { defaultValue: fallback });
   const activePreset = settings.agent.model_preset || "default";
   const activeProvider = settings.agent.resolved_provider ?? settings.agent.provider;
+  const activeProviderConfigured = settingsProviderConfigured(settings, activeProvider);
+  const activeProviderLabel = providerDisplayLabel(settings.providers, activeProvider);
+  const activeModelValue = activeProviderConfigured
+    ? settings.agent.model
+    : tx("settings.values.notConfigured", "Not configured");
+  const activeModelCaption = activeProviderConfigured
+    ? `${activeProvider} · ${activePreset}`
+    : activeProviderLabel || settings.agent.model
+      ? [activeProviderLabel, settings.agent.model].filter(Boolean).join(" · ")
+      : tx("settings.byok.noConfiguredProviders", "No configured providers");
   const webStatus = settings.web.enable
     ? tx("settings.values.enabled", "Enabled")
     : tx("settings.values.disabled", "Disabled");
@@ -1515,48 +1629,23 @@ function OverviewSettings({
       ? tx("settings.values.configured", "Configured")
       : tx("settings.values.notConfigured", "Not configured")
   }`;
+  const isNativeHost = (settings.surface ?? settings.runtime_surface) === "native";
+  const workspaceCaption = shortWorkspacePath(settings.runtime.workspace_path);
+  const runtimeTitle = isNativeHost
+    ? tx("settings.rows.engine", "Engine")
+    : tx("settings.rows.gateway", "Gateway");
+  const runtimeValue = isNativeHost
+    ? tx("settings.values.privateEngine", "Private engine")
+    : `${settings.runtime.gateway_host}:${settings.runtime.gateway_port}`;
+  const runtimeCaption = isNativeHost
+    ? tx("settings.values.unixSocket", "Unix socket")
+    : requiresRestart
+      ? tx("settings.values.restartPending", "Restart pending")
+      : tx("settings.values.ready", "Ready");
   return (
     <div className="space-y-7">
       <section>
-        <div className="overflow-hidden rounded-[22px] border border-border/45 bg-card/86 shadow-[0_18px_65px_rgba(15,23,42,0.075)] backdrop-blur-xl dark:border-white/10 dark:shadow-[0_18px_65px_rgba(0,0,0,0.24)]">
-          <div className="flex flex-col gap-4 px-5 py-5 sm:flex-row sm:items-center sm:justify-between">
-            <div className="flex min-w-0 items-center gap-3">
-              <NanobotBrandLogo size="lg" testId="overview-nanobot-logo" />
-              <div className="min-w-0">
-                <div className="text-[12px] font-medium text-muted-foreground">nanobot</div>
-                <div className="mt-0.5 truncate text-[18px] font-semibold leading-6 text-foreground">
-                  {settings.agent.model}
-                </div>
-                <div className="mt-0.5 truncate text-[13px] leading-5 text-muted-foreground">
-                  {activeProvider} · {activePreset}
-                </div>
-              </div>
-            </div>
-            <div className="flex flex-wrap items-center gap-2 sm:justify-end">
-              <StatusPill tone={requiresRestart ? "neutral" : "success"}>
-                {requiresRestart
-                  ? tx("settings.values.restartPending", "Restart pending")
-                  : tx("settings.values.ready", "Ready")}
-              </StatusPill>
-              {requiresRestart && onRestart ? (
-                <Button
-                  size="sm"
-                  variant="ghost"
-                  onClick={onRestart}
-                  disabled={isRestarting}
-                  className="rounded-full"
-                >
-                  {isRestarting ? (
-                    <Loader2 className="mr-1.5 h-3.5 w-3.5 animate-spin" aria-hidden />
-                  ) : (
-                    <RotateCcw className="mr-1.5 h-3.5 w-3.5" aria-hidden />
-                  )}
-                  {isRestarting ? t("app.system.restarting") : t("app.system.restart")}
-                </Button>
-              ) : null}
-            </div>
-          </div>
-        </div>
+        <TokenUsageHeatmap usage={settings.usage} />
       </section>
 
       <section>
@@ -1566,8 +1655,8 @@ function OverviewSettings({
             icon={Bot}
             valueLogoProvider={activeProvider}
             title={tx("settings.overview.model", "Current model")}
-            value={settings.agent.model}
-            caption={`${activeProvider} · ${activePreset}`}
+            value={activeModelValue}
+            caption={activeModelCaption}
             showBrandLogos={showBrandLogos}
             onClick={() => onSelectSection("models")}
           />
@@ -1603,20 +1692,16 @@ function OverviewSettings({
         <SettingsGroup>
           <OverviewListRow
             icon={Server}
-            title={tx("settings.rows.gateway", "Gateway")}
-            value={`${settings.runtime.gateway_host}:${settings.runtime.gateway_port}`}
-            caption={
-              requiresRestart
-                ? tx("settings.values.restartPending", "Restart pending")
-                : tx("settings.values.ready", "Ready")
-            }
+            title={runtimeTitle}
+            value={runtimeValue}
+            caption={runtimeCaption}
             onClick={() => onSelectSection("runtime")}
           />
           <OverviewListRow
             icon={HardDrive}
             title={tx("settings.overview.workspace", "Workspace")}
-            value={settings.runtime.workspace_path}
-            caption={settings.runtime.config_path}
+            value={tx("settings.values.defaultWorkspace", "Default workspace")}
+            caption={workspaceCaption}
             onClick={() => onSelectSection("runtime")}
           />
         </SettingsGroup>
@@ -1625,6 +1710,219 @@ function OverviewSettings({
   );
 }
 
+type TokenUsagePayload = NonNullable<SettingsPayload["usage"]>;
+type TokenUsageDay = TokenUsagePayload["days"][number];
+type TokenUsageCell = {
+  date: string;
+  total: number;
+  estimated: number;
+  requests: number;
+  sources: NonNullable<TokenUsageDay["sources"]>;
+  future: boolean;
+};
+type TokenUsageMonthLabel = {
+  label: string;
+  column: number;
+};
+
+const TOKEN_HEATMAP_CELLS = 371;
+const TOKEN_HEATMAP_COLUMNS = Math.ceil(TOKEN_HEATMAP_CELLS / 7);
+const TOKEN_USAGE_SOURCE_ORDER = ["user", "api", "cron", "dream", "system"] as const;
+
+function startOfUtcDay(date: Date): Date {
+  return new Date(Date.UTC(date.getUTCFullYear(), date.getUTCMonth(), date.getUTCDate()));
+}
+
+function addUtcDays(date: Date, days: number): Date {
+  const next = new Date(date);
+  next.setUTCDate(next.getUTCDate() + days);
+  return next;
+}
+
+function isoDay(date: Date): string {
+  return date.toISOString().slice(0, 10);
+}
+
+function buildTokenUsageCalendar(
+  days: TokenUsageDay[] | undefined,
+  monthFormatter: Intl.DateTimeFormat,
+): { cells: TokenUsageCell[]; monthLabels: TokenUsageMonthLabel[] } {
+  const byDate = new Map((days ?? []).map((day) => [day.date, day]));
+  const today = startOfUtcDay(new Date());
+  const end = addUtcDays(today, 6 - today.getUTCDay());
+  const start = addUtcDays(end, -(TOKEN_HEATMAP_CELLS - 1));
+  const seenMonths = new Set<string>();
+  const monthLabels: TokenUsageMonthLabel[] = [];
+
+  const cells = Array.from({ length: TOKEN_HEATMAP_CELLS }, (_, index) => {
+    const date = addUtcDays(start, index);
+    const key = isoDay(date);
+    const row = byDate.get(key);
+    const monthKey = key.slice(0, 7);
+    if (!seenMonths.has(monthKey)) {
+      seenMonths.add(monthKey);
+      monthLabels.push({
+        label: monthFormatter.format(date),
+        column: Math.floor(index / 7) + 1,
+      });
+    }
+    return {
+      date: key,
+      total: row?.total_tokens ?? 0,
+      estimated: row?.estimated_tokens ?? 0,
+      requests: row?.requests ?? 0,
+      sources: row?.sources ?? {},
+      future: date > today,
+    };
+  });
+  return { cells, monthLabels };
+}
+
+function tokenUsageSourceLabel(
+  source: string,
+  tx: (key: string, fallback: string, values?: Record<string, unknown>) => string,
+): string {
+  if (source === "user") return tx("settings.usage.sources.user", "Chat");
+  if (source === "api") return tx("settings.usage.sources.api", "API");
+  if (source === "cron") return tx("settings.usage.sources.cron", "Automations");
+  if (source === "dream") return tx("settings.usage.sources.dream", "Memory");
+  return tx("settings.usage.sources.system", "System");
+}
+
+function tokenUsageSourceBreakdown(
+  cell: TokenUsageCell,
+  tx: (key: string, fallback: string, values?: Record<string, unknown>) => string,
+): string {
+  const known = TOKEN_USAGE_SOURCE_ORDER.filter((source) => cell.sources[source]?.total_tokens > 0);
+  const extra = Object.keys(cell.sources)
+    .filter((source) => !TOKEN_USAGE_SOURCE_ORDER.includes(source as typeof TOKEN_USAGE_SOURCE_ORDER[number]))
+    .filter((source) => cell.sources[source]?.total_tokens > 0)
+    .sort();
+  return [...known, ...extra]
+    .map((source) => {
+      const label = tokenUsageSourceLabel(source, tx);
+      const tokens = formatCompactTokens(cell.sources[source]?.total_tokens ?? 0);
+      return `${label} ${tokens}`;
+    })
+    .join(" · ");
+}
+
+function formatCompactTokens(tokens: number): string {
+  if (tokens >= 1_000_000) return `${(tokens / 1_000_000).toFixed(tokens >= 10_000_000 ? 0 : 1)}M`;
+  if (tokens >= 1_000) return `${(tokens / 1_000).toFixed(tokens >= 10_000 ? 0 : 1)}K`;
+  return String(tokens);
+}
+
+function tokenUsageLevel(tokens: number, max: number): number {
+  if (tokens <= 0 || max <= 0) return 0;
+  const ratio = tokens / max;
+  if (ratio >= 0.75) return 4;
+  if (ratio >= 0.45) return 3;
+  if (ratio >= 0.2) return 2;
+  return 1;
+}
+
+function tokenUsageCellClass(level: number, future: boolean): string {
+  if (future) return "bg-transparent ring-1 ring-neutral-200/70 dark:ring-white/[0.045]";
+  if (level === 4) return "bg-sky-300 dark:bg-sky-300";
+  if (level === 3) return "bg-sky-400/85 dark:bg-sky-500/80";
+  if (level === 2) return "bg-sky-500/60 dark:bg-sky-700/85";
+  if (level === 1) return "bg-sky-500/30 dark:bg-sky-900/80";
+  return "bg-neutral-200/70 ring-1 ring-black/[0.025] dark:bg-white/[0.08] dark:ring-white/[0.035]";
+}
+
+function TokenUsageHeatmap({ usage }: { usage?: TokenUsagePayload }) {
+  const { t, i18n } = useTranslation();
+  const tx = (key: string, fallback: string, values?: Record<string, unknown>) =>
+    t(key, { defaultValue: fallback, ...(values ?? {}) });
+  const monthFormatter = useMemo(
+    () => new Intl.DateTimeFormat(i18n.language, { month: "short", timeZone: "UTC" }),
+    [i18n.language],
+  );
+  const { cells, monthLabels } = useMemo(
+    () => buildTokenUsageCalendar(usage?.days, monthFormatter),
+    [monthFormatter, usage?.days],
+  );
+  const maxTokens = Math.max(0, ...cells.map((cell) => cell.total));
+
+  return (
+    <div className="overflow-x-auto pb-1 [scrollbar-width:none] [&::-webkit-scrollbar]:hidden">
+      <div className="mx-auto w-full min-w-[760px] max-w-[1054px] px-0.5">
+        <div className="mb-2 flex justify-end">
+          <span className="text-[11px] font-normal leading-none text-muted-foreground/64">
+            {tx("settings.usage.shortTitle", "Token Usage")}
+          </span>
+        </div>
+        <div
+          className="mb-2 grid h-4 gap-1.5 text-[10px] font-normal leading-4 text-muted-foreground/62"
+          style={{ gridTemplateColumns: `repeat(${TOKEN_HEATMAP_COLUMNS}, minmax(0, 1fr))` }}
+          aria-hidden
+        >
+          {monthLabels.map((month) => (
+            <span
+              key={`${month.label}-${month.column}`}
+              className="truncate"
+              style={{ gridColumnStart: month.column, gridColumnEnd: "span 4" }}
+            >
+              {month.label}
+            </span>
+          ))}
+        </div>
+        <div
+          className="grid grid-flow-col grid-rows-7 gap-1.5"
+          style={{ gridTemplateColumns: `repeat(${TOKEN_HEATMAP_COLUMNS}, minmax(0, 1fr))` }}
+          aria-label={tx("settings.usage.title", "Token activity")}
+        >
+          <TooltipProvider delayDuration={120} skipDelayDuration={80}>
+            {cells.map((cell) => {
+              const level = tokenUsageLevel(cell.total, maxTokens);
+              const baseLabel = cell.future
+                ? cell.date
+                : tx("settings.usage.cellTitle", "{{date}}: {{tokens}} tokens, {{requests}} requests", {
+                    date: cell.date,
+                    tokens: formatCompactTokens(cell.total),
+                    requests: cell.requests,
+                  });
+              const label = cell.future || cell.estimated <= 0
+                ? baseLabel
+                : `${baseLabel} · ${
+                    cell.estimated >= cell.total
+                      ? tx("settings.usage.estimated", "estimated")
+                      : tx("settings.usage.includesEstimates", "includes estimates")
+                  }`;
+              const breakdown = cell.future ? "" : tokenUsageSourceBreakdown(cell, tx);
+              const ariaLabel = breakdown ? `${label} · ${breakdown}` : label;
+              return (
+                <Tooltip key={cell.date}>
+                  <TooltipTrigger asChild>
+                    <span
+                      aria-label={ariaLabel}
+                      className={cn(
+                        "aspect-square w-full rounded-[4px] transition-transform hover:scale-110",
+                        tokenUsageCellClass(level, cell.future),
+                      )}
+                    />
+                  </TooltipTrigger>
+                  <TooltipContent
+                    side="top"
+                    align="center"
+                    className="rounded-[10px] border-border/45 bg-popover px-2.5 py-1.5 text-[11px] font-normal text-popover-foreground shadow-lg"
+                  >
+                    <span className="block">{label}</span>
+                    {breakdown ? (
+                      <span className="mt-1 block text-muted-foreground">{breakdown}</span>
+                    ) : null}
+                  </TooltipContent>
+                </Tooltip>
+              );
+            })}
+          </TooltipProvider>
+        </div>
+      </div>
+    </div>
+  );
+}
+
 function AppearanceSettings({
   theme,
   onToggleTheme,
@@ -1885,9 +2183,8 @@ function ModelsSettings({
   const { t } = useTranslation();
   const tx = (key: string, fallback: string) => t(key, { defaultValue: fallback });
   const configuredProviders = settings.providers.filter((provider) => provider.configured);
-  const oauthProviders = settings.providers.filter((provider) => provider.auth_type === "oauth");
   const showAutoProvider = defaultPreset(settings)?.provider === "auto" || form.provider === "auto";
-  const selectableProviders = uniqueProviders([...configuredProviders, ...oauthProviders]);
+  const selectableProviders = uniqueProviders(configuredProviders);
   const providerOptions = showAutoProvider
     ? [{ name: "auto", label: tx("settings.values.auto", "Auto") }, ...selectableProviders]
     : selectableProviders;
@@ -1900,6 +2197,7 @@ function ModelsSettings({
   const selectedProviderNeedsSignIn =
     selectedProvider?.auth_type === "oauth" && !selectedProvider.configured;
   const selectedProviderSigningIn = providerSaving === selectedProvider?.name;
+  const selectedProviderConfigured = settingsProviderConfigured(settings, form.provider);
   const modelFieldsMissing =
     !form.model.trim() ||
     !form.provider.trim() ||
@@ -1918,6 +2216,7 @@ function ModelsSettings({
               settings={settings}
               draftModel={form.model}
               draftProvider={form.provider}
+              providerConfigured={selectedProviderConfigured}
               showProviderLogos={showBrandLogos}
               onChange={(modelPreset) => {
                 const nextPreset = settings.model_presets.find((preset) => preset.name === modelPreset);
@@ -4060,10 +4359,12 @@ function RuntimeSettings({
       <section>
         <SettingsSectionTitle>{t("settings.sections.system")}</SettingsSectionTitle>
         <SettingsGroup>
-          <ReadOnlyRow
-            title={tx("settings.rows.gateway", "Gateway")}
-            value={`${settings.runtime.gateway_host}:${settings.runtime.gateway_port}`}
-          />
+          {!isNativeHost ? (
+            <ReadOnlyRow
+              title={tx("settings.rows.gateway", "Gateway")}
+              value={`${settings.runtime.gateway_host}:${settings.runtime.gateway_port}`}
+            />
+          ) : null}
           <ReadOnlyRow title={t("settings.rows.configPath")} value={settings.runtime.config_path} />
           <ReadOnlyRow title={tx("settings.rows.workspacePath", "Default workspace")} value={settings.runtime.workspace_path} />
           {onRestart && !requiresRestartPending ? (
@@ -4369,7 +4670,14 @@ function ModelIdPicker({
   const [error, setError] = useState<string | null>(null);
   const effectiveProvider =
     provider === "auto" ? settings.agent.resolved_provider ?? provider : provider;
-  const canFetchModels = Boolean(effectiveProvider && effectiveProvider !== "auto");
+  const hasConcreteProvider = Boolean(effectiveProvider && effectiveProvider !== "auto");
+  const providerRow = settingsProviderRow(settings, effectiveProvider);
+  const providerConfigured = settingsProviderConfigured(settings, effectiveProvider);
+  const providerRequiresConfiguration = hasConcreteProvider && !providerConfigured;
+  const providerUsesManualModelIds =
+    hasConcreteProvider && providerConfigured && providerRow?.auth_type === "oauth";
+  const canFetchModels =
+    hasConcreteProvider && providerConfigured && !providerUsesManualModelIds;
   const normalizedQuery = query.trim().toLowerCase();
   const providerModels = payload?.models ?? [];
   const visibleModels = providerModels
@@ -4390,13 +4698,15 @@ function ModelIdPicker({
   const hasModelList = payload?.status === "available";
   const showModels = Boolean(hasModelList && payload && (!isCatalog || normalizedQuery));
   const customCandidate = query.trim();
+  const allowCustomModel = !providerRequiresConfiguration;
   const exactQueryMatch = providerModels.some((model) => model.id === customCandidate);
   const providerModelCount = payload?.model_count ?? providerModels.length;
+  const modelUnconfigured = !value.trim() || !providerConfigured;
 
   useEffect(() => {
     if (!open) return;
-    setQuery("");
-  }, [open, effectiveProvider]);
+    setQuery(providerUsesManualModelIds || !hasConcreteProvider ? value : "");
+  }, [open, effectiveProvider, hasConcreteProvider, providerUsesManualModelIds, value]);
 
   useEffect(() => {
     if (!open || !shouldFetchModels) {
@@ -4443,7 +4753,11 @@ function ModelIdPicker({
       )}
     >
       <span className="flex min-w-0 items-center gap-2">
-        <ProviderPickerIcon provider={effectiveProvider} showBrandLogos={showProviderLogos} />
+        <ProviderPickerIcon
+          provider={effectiveProvider}
+          showBrandLogos={showProviderLogos}
+          unconfigured={!providerConfigured}
+        />
         <span className="min-w-0 truncate font-medium text-foreground">
           {model.label ?? model.id}
         </span>
@@ -4467,7 +4781,11 @@ function ModelIdPicker({
           )}
         >
           <span className="flex min-w-0 items-center gap-2">
-            <ProviderPickerIcon provider={effectiveProvider} showBrandLogos={showProviderLogos} />
+            <ProviderPickerIcon
+              provider={effectiveProvider}
+              showBrandLogos={showProviderLogos}
+              unconfigured={modelUnconfigured}
+            />
             <span
               className={cn(
                 "min-w-0 truncate font-medium",
@@ -4500,7 +4818,15 @@ function ModelIdPicker({
           </div>
         </div>
 
-        {!canFetchModels ? (
+        {providerRequiresConfiguration ? (
+          <div className="px-2 py-1.5 text-[11px] leading-4 text-muted-foreground">
+            {tx("settings.models.providerNotConfigured", "Configure this provider before loading models.")}
+          </div>
+        ) : providerUsesManualModelIds ? (
+          <div className="px-2 py-1.5 text-[11px] leading-4 text-muted-foreground">
+            {tx("settings.models.unsupportedModelList", "Type a model ID manually.")}
+          </div>
+        ) : !canFetchModels ? (
           <div className="px-2 py-1.5 text-[11px] leading-4 text-muted-foreground">
             {tx("settings.models.autoProviderCustomOnly", "Auto provider mode uses custom model IDs.")}
           </div>
@@ -4544,7 +4870,7 @@ function ModelIdPicker({
           </div>
         ) : null}
 
-        {customCandidate && !exactQueryMatch && customCandidate !== value ? (
+        {allowCustomModel && customCandidate && !exactQueryMatch && customCandidate !== value ? (
           <>
             {showModels ? <DropdownMenuSeparator /> : null}
             <DropdownMenuItem
@@ -4581,17 +4907,31 @@ function formatContextWindow(tokens: number): string {
 function ProviderPickerIcon({
   provider,
   showBrandLogos,
+  unconfigured = false,
 }: {
   provider: string;
   showBrandLogos: boolean;
+  unconfigured?: boolean;
 }) {
   const [logoIndex, setLogoIndex] = useState(0);
   const brand = providerBrand(provider);
-  const Icon = PROVIDER_ICONS[provider] ?? Sparkles;
+  const Icon = PROVIDER_ICONS[provider] ?? Hexagon;
   const logoUrl = brand?.logoUrls[logoIndex];
 
   useEffect(() => setLogoIndex(0), [provider]);
 
+  if (unconfigured) {
+    return (
+      <span
+        data-testid="provider-picker-unconfigured-icon"
+        className="grid h-5 w-5 shrink-0 place-items-center text-amber-700 dark:text-amber-200"
+        aria-hidden
+      >
+        <CircleAlert className="h-4 w-4" strokeWidth={1.8} />
+      </span>
+    );
+  }
+
   if (showBrandLogos && logoUrl) {
     return (
       <span
@@ -4901,32 +5241,6 @@ function ProviderIcon({
   );
 }
 
-function NanobotBrandLogo({
-  size = "sm",
-  testId,
-}: {
-  size?: "sm" | "lg";
-  testId?: string;
-}) {
-  return (
-    <span
-      data-testid={testId}
-      className={cn(
-        "grid shrink-0 place-items-center overflow-hidden border border-border/45 bg-background shadow-[inset_0_0_0_1px_rgba(0,0,0,0.025)]",
-        size === "lg" ? "h-12 w-12 rounded-[16px]" : "h-9 w-9 rounded-[12px]",
-      )}
-      aria-hidden
-    >
-      <img
-        src={NANOBOT_ICON_SRC}
-        alt=""
-        className={cn("select-none object-contain", size === "lg" ? "h-10 w-10" : "h-7 w-7")}
-        draggable={false}
-      />
-    </span>
-  );
-}
-
 function OverviewRowIcon({
   icon: Icon,
 }: {
@@ -5090,6 +5404,7 @@ function ModelPresetPicker({
   settings,
   draftModel,
   draftProvider,
+  providerConfigured,
   showProviderLogos,
   onChange,
   onCreateConfiguration,
@@ -5099,6 +5414,7 @@ function ModelPresetPicker({
   settings: SettingsPayload;
   draftModel: string;
   draftProvider: string;
+  providerConfigured: boolean;
   showProviderLogos: boolean;
   onChange: (preset: string) => void;
   onCreateConfiguration: () => void;
@@ -5126,6 +5442,7 @@ function ModelPresetPicker({
               settings={settings}
               draftModel={draftModel}
               draftProvider={draftProvider}
+              forceUnconfigured={selectedPreset?.is_default ? !providerConfigured : undefined}
               showProviderLogos={showProviderLogos}
               compact
             />
@@ -5190,6 +5507,7 @@ function ModelPresetOptionContent({
   settings,
   draftModel,
   draftProvider,
+  forceUnconfigured,
   showProviderLogos,
   compact = false,
 }: {
@@ -5197,27 +5515,50 @@ function ModelPresetOptionContent({
   settings: SettingsPayload;
   draftModel: string;
   draftProvider: string;
+  forceUnconfigured?: boolean;
   showProviderLogos: boolean;
   compact?: boolean;
 }) {
+  const { t } = useTranslation();
+  const tx = (key: string, fallback: string) => t(key, { defaultValue: fallback });
   const provider = modelPresetProviderKey(preset, settings, {
     draftProvider: preset.is_default ? draftProvider : undefined,
   });
   const model = preset.is_default ? draftModel : preset.model;
   const providerName = providerDisplayLabel(settings.providers, provider);
+  const providerConfigured =
+    forceUnconfigured === undefined
+      ? settingsProviderConfigured(settings, provider)
+      : !forceUnconfigured;
+  const title = providerConfigured ? model || preset.label : tx("settings.values.notConfigured", "Not configured");
+  const caption = providerConfigured
+    ? `${providerName}${preset.label ? ` · ${preset.label}` : ""}`
+    : providerName || model || preset.label
+      ? [providerName, model || preset.label].filter(Boolean).join(" · ")
+      : tx("settings.byok.noConfiguredProviders", "No configured providers");
   return (
     <span className="flex min-w-0 items-center gap-2.5">
-      <ProviderPickerIcon provider={provider} showBrandLogos={showProviderLogos} />
+      <ProviderPickerIcon
+        provider={provider}
+        showBrandLogos={showProviderLogos}
+        unconfigured={!providerConfigured}
+      />
       <span className="min-w-0 text-left leading-tight">
-        <span className="block truncate font-medium text-foreground">{model || preset.label}</span>
+        <span
+          className={cn(
+            "block truncate font-medium",
+            providerConfigured ? "text-foreground" : "text-amber-800 dark:text-amber-200",
+          )}
+        >
+          {title}
+        </span>
         <span
           className={cn(
             "mt-0.5 block truncate text-muted-foreground",
             compact ? "text-[11.5px]" : "text-[12px]",
           )}
         >
-          {providerName}
-          {preset.label ? ` · ${preset.label}` : ""}
+          {caption}
         </span>
       </span>
     </span>
diff --git a/webui/src/components/thread/AgentActivityCluster.tsx b/webui/src/components/thread/AgentActivityCluster.tsx
index aaf5a7be0..0210b0559 100644
--- a/webui/src/components/thread/AgentActivityCluster.tsx
+++ b/webui/src/components/thread/AgentActivityCluster.tsx
@@ -173,6 +173,7 @@ interface AgentActivityClusterProps {
   turnLatencyMs?: number;
   cliApps?: CliAppInfo[];
   mcpPresets?: McpPresetInfo[];
+  onOpenFilePreview?: (path: string) => void;
 }
 
 /**
@@ -186,6 +187,7 @@ export function AgentActivityCluster({
   turnLatencyMs,
   cliApps = [],
   mcpPresets = [],
+  onOpenFilePreview,
 }: AgentActivityClusterProps) {
   const { t } = useTranslation();
   const fileEdits = useMemo(
@@ -423,6 +425,7 @@ export function AgentActivityCluster({
         added={added}
         deleted={deleted}
         hasDiffStats={hasDiffStats}
+        onOpenFilePreview={onOpenFilePreview}
       />
     );
   }
@@ -449,6 +452,8 @@ export function AgentActivityCluster({
           <FileReferenceChip
             path={singleFilePath}
             tooltipPath={singleFileTooltipPath}
+            previewPath={singleFileTooltipPath || singleFilePath}
+            onOpen={onOpenFilePreview}
             active={hasLiveEditingFiles}
             className="-my-0.5 min-w-0"
             textClassName="text-xs"
@@ -494,6 +499,7 @@ export function AgentActivityCluster({
                       key={m.id}
                       text={m.reasoning ?? ""}
                       streaming={isTurnStreaming && !!m.reasoningStreaming}
+                      onOpenFilePreview={onOpenFilePreview}
                     />
                   );
                 }
@@ -510,7 +516,12 @@ export function AgentActivityCluster({
                 }
                 return null;
               })}
-              {fileEdits.length ? <FileEditGroup edits={fileEdits} /> : null}
+              {fileEdits.length ? (
+                <FileEditGroup
+                  edits={fileEdits}
+                  onOpenFilePreview={onOpenFilePreview}
+                />
+              ) : null}
             </div>
           </div>
         </div>
@@ -537,6 +548,7 @@ function FileEditFlatActivity({
   added,
   deleted,
   hasDiffStats,
+  onOpenFilePreview,
 }: {
   edits: FileEditSummary[];
   active: boolean;
@@ -550,6 +562,7 @@ function FileEditFlatActivity({
   added: number;
   deleted: number;
   hasDiffStats: boolean;
+  onOpenFilePreview?: (path: string) => void;
 }) {
   const showRows = edits.length > 1 || edits.some((edit) => edit.status === "error" || edit.pending);
   return (
@@ -569,6 +582,8 @@ function FileEditFlatActivity({
           <FileReferenceChip
             path={singleFilePath}
             tooltipPath={singleFileTooltipPath}
+            previewPath={singleFileTooltipPath || singleFilePath}
+            onOpen={onOpenFilePreview}
             active={hasLiveEditingFiles}
             className="-my-0.5 min-w-0"
             textClassName="text-xs"
@@ -583,7 +598,7 @@ function FileEditFlatActivity({
       </div>
       {showRows ? (
         <div className="mt-0.5 pl-4">
-          <FileEditGroup edits={edits} />
+          <FileEditGroup edits={edits} onOpenFilePreview={onOpenFilePreview} />
         </div>
       ) : null}
     </div>
diff --git a/webui/src/components/thread/PromptRail.tsx b/webui/src/components/thread/PromptRail.tsx
index 7bcf605f9..e04f9f0dc 100644
--- a/webui/src/components/thread/PromptRail.tsx
+++ b/webui/src/components/thread/PromptRail.tsx
@@ -34,14 +34,16 @@ interface PromptMarker {
 }
 
 const MIN_PROMPTS_FOR_RAIL = 3;
-const RAIL_MIN_SCROLL_RANGE_PX = 240;
+const RAIL_MIN_SCROLL_RANGE_PX = 80;
 const DENSE_PROMPT_THRESHOLD = 30;
 const DENSE_BUCKET_HEIGHT_PX = 12;
 const DENSE_BUCKET_FALLBACK_COUNT = 32;
 const DENSE_BUCKET_MAX_COUNT = 42;
 const MARKER_MIN_GAP_PX = 9;
-const MARKER_BASE_WIDTH_PX = 26;
-const MARKER_MAX_WIDTH_PX = 42;
+const MARKER_BASE_WIDTH_PX = 16;
+const MARKER_MAX_WIDTH_PX = 28;
+const MEASURE_RETRY_FRAMES = 4;
+const RAIL_REVEAL_MS = 1400;
 
 export function PromptRail({
   bottomOffset,
@@ -52,6 +54,19 @@ export function PromptRail({
   const promptAnchors = useMemo(() => userPromptAnchors(messages), [messages]);
   const [markers, setMarkers] = useState<PromptMarker[]>([]);
   const [activePromptId, setActivePromptId] = useState<string | null>(null);
+  const [revealed, setRevealed] = useState(false);
+  const revealTimeoutRef = useRef<number | null>(null);
+
+  const revealTemporarily = useCallback(() => {
+    setRevealed(true);
+    if (revealTimeoutRef.current !== null) {
+      window.clearTimeout(revealTimeoutRef.current);
+    }
+    revealTimeoutRef.current = window.setTimeout(() => {
+      setRevealed(false);
+      revealTimeoutRef.current = null;
+    }, RAIL_REVEAL_MS);
+  }, []);
 
   const updateMarkers = useCallback(() => {
     const scrollEl = scrollRef.current;
@@ -74,8 +89,18 @@ export function PromptRail({
   }, [promptAnchors, scrollRef]);
 
   useEffect(() => {
-    updateMarkers();
-  }, [updateMarkers]);
+    let frame = 0;
+    let remainingFrames = MEASURE_RETRY_FRAMES;
+    const measure = () => {
+      updateMarkers();
+      remainingFrames -= 1;
+      if (remainingFrames > 0) {
+        frame = window.requestAnimationFrame(measure);
+      }
+    };
+    measure();
+    return () => window.cancelAnimationFrame(frame);
+  }, [bottomOffset, updateMarkers]);
 
   useEffect(() => {
     const scrollEl = scrollRef.current;
@@ -84,6 +109,7 @@ export function PromptRail({
     let frame = 0;
     const schedule = () => {
       window.cancelAnimationFrame(frame);
+      revealTemporarily();
       frame = window.requestAnimationFrame(updateMarkers);
     };
 
@@ -94,7 +120,7 @@ export function PromptRail({
       scrollEl.removeEventListener("scroll", schedule);
       window.removeEventListener("resize", schedule);
     };
-  }, [scrollRef, updateMarkers]);
+  }, [revealTemporarily, scrollRef, updateMarkers]);
 
   useEffect(() => {
     const scrollEl = scrollRef.current;
@@ -105,22 +131,36 @@ export function PromptRail({
     return () => observer.disconnect();
   }, [scrollRef, updateMarkers]);
 
+  useEffect(() => {
+    return () => {
+      if (revealTimeoutRef.current !== null) {
+        window.clearTimeout(revealTimeoutRef.current);
+      }
+    };
+  }, []);
+
   if (markers.length === 0) return null;
 
   const maxMarkerCount = Math.max(...markers.map((marker) => marker.count));
+  const activeMarkerIndex = markers.findIndex((marker) =>
+    marker.ids.includes(activePromptId ?? ""),
+  );
 
   return (
     <div
       ref={railRef}
       aria-label="User prompt navigation"
       className={cn(
-        "pointer-events-none absolute right-6 top-12 z-20 hidden w-12 md:block",
+        "group pointer-events-auto absolute right-4 top-14 z-20 hidden w-8 opacity-70 md:block",
+        "transition-opacity duration-200 hover:opacity-100",
         "motion-safe:animate-in motion-safe:fade-in-0 motion-safe:duration-200",
       )}
       style={{ bottom: Math.max(80, bottomOffset) }}
     >
       {markers.map((marker) => {
+        const index = markers.indexOf(marker);
         const active = marker.ids.includes(activePromptId ?? "");
+        const nearActive = activeMarkerIndex < 0 || Math.abs(index - activeMarkerIndex) <= 1;
         return (
           <button
             key={marker.ids.join("|")}
@@ -129,12 +169,16 @@ export function PromptRail({
             aria-label={`Jump to prompt: ${marker.label}`}
             onClick={() => jumpToPrompt(scrollRef.current, marker.ids[marker.ids.length - 1])}
             className={cn(
-              "pointer-events-auto absolute right-0 h-1.5 -translate-y-1/2 rounded-full",
-              "bg-muted-foreground/30 transition-all duration-150",
-              "hover:bg-blue-500/80 focus-visible:bg-blue-500",
+              "absolute right-0 h-[3px] -translate-y-1/2 rounded-full",
+              "bg-foreground/20 transition-[background-color,opacity,transform,width] duration-200",
+              "hover:bg-blue-500/70 hover:opacity-100 hover:scale-x-110",
+              "focus-visible:bg-blue-500 focus-visible:opacity-100 focus-visible:scale-x-110",
               "focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-blue-400/60",
-              marker.count > 1 && "bg-muted-foreground/45",
-              active && "bg-foreground shadow-sm",
+              marker.count > 1 && "bg-foreground/30",
+              active && "h-1 bg-foreground/65 opacity-80 shadow-sm",
+              !active && nearActive && "opacity-25 group-hover:opacity-55",
+              !active && !nearActive && !revealed && "opacity-0 group-hover:opacity-40",
+              !active && !nearActive && revealed && "opacity-35",
             )}
             style={{
               top: `${marker.topPercent}%`,
diff --git a/webui/src/components/thread/ThreadComposer.tsx b/webui/src/components/thread/ThreadComposer.tsx
index 44029c036..1c0c7cbdc 100644
--- a/webui/src/components/thread/ThreadComposer.tsx
+++ b/webui/src/components/thread/ThreadComposer.tsx
@@ -94,6 +94,8 @@ interface ThreadComposerProps {
   modelLabel?: string | null;
   modelProvider?: string | null;
   modelProviderLabel?: string | null;
+  modelNeedsSetup?: boolean;
+  onModelBadgeClick?: () => void;
   variant?: "thread" | "hero";
   slashCommands?: SlashCommand[];
   cliApps?: CliAppInfo[];
@@ -647,6 +649,8 @@ export function ThreadComposer({
   modelLabel = null,
   modelProvider = null,
   modelProviderLabel = null,
+  modelNeedsSetup = false,
+  onModelBadgeClick,
   variant = "thread",
   slashCommands = [],
   cliApps = [],
@@ -759,17 +763,21 @@ export function ThreadComposer({
   );
   const hasErrors = images.some((img) => img.status === "error");
 
+  const hasComposerContent = value.trim().length > 0 || readyImages.length > 0;
   const canSend =
     !disabled
+    && !modelNeedsSetup
     && !encoding
     && !hasErrors
-    && (value.trim().length > 0 || readyImages.length > 0);
+    && hasComposerContent;
+  const canOpenModelSettings = Boolean(modelNeedsSetup && onModelBadgeClick && !disabled);
   const canQueueGuidance =
     isStreaming
     && !disabled
+    && !modelNeedsSetup
     && !encoding
     && !hasErrors
-    && (value.trim().length > 0 || readyImages.length > 0)
+    && hasComposerContent
     && !value.trimStart().startsWith("/");
 
   const slashQuery = useMemo(() => {
@@ -1181,6 +1189,10 @@ export function ThreadComposer({
   }, [onStop, queuedPrompts.length]);
 
   const submit = useCallback(() => {
+    if (modelNeedsSetup) {
+      onModelBadgeClick?.();
+      return;
+    }
     if (!canSend) return;
     const trimmed = value.trim();
     const content = trimmed;
@@ -1219,6 +1231,8 @@ export function ThreadComposer({
     canSend,
     clear,
     clearComposerText,
+    modelNeedsSetup,
+    onModelBadgeClick,
     onSend,
     readyImages,
     value,
@@ -1533,24 +1547,32 @@ export function ThreadComposer({
                 label={modelLabel}
                 provider={modelProvider}
                 providerLabel={modelProviderLabel}
+                needsSetup={modelNeedsSetup}
                 isHero={isHero}
+                onClick={modelNeedsSetup ? onModelBadgeClick : undefined}
               />
             ) : null}
             <Button
-              type={showStopButton ? "button" : "submit"}
+              type={showStopButton || modelNeedsSetup ? "button" : "submit"}
               size="icon"
-              disabled={showStopButton ? disabled : !canSend}
-              aria-label={showStopButton ? t("thread.composer.stop") : t("thread.composer.send")}
-              onClick={showStopButton ? handleStop : undefined}
+              disabled={showStopButton ? disabled : !canSend && !canOpenModelSettings}
+              aria-label={
+                showStopButton
+                  ? t("thread.composer.stop")
+                  : modelNeedsSetup
+                    ? t("thread.composer.configureModel", { defaultValue: "Configure model" })
+                    : t("thread.composer.send")
+              }
+              onClick={showStopButton ? handleStop : modelNeedsSetup ? onModelBadgeClick : undefined}
               className={cn(
                 "rounded-full transition-transform",
                 showStopButton
                   ? "border border-border/70 bg-card text-foreground/85 shadow-[0_3px_10px_rgba(15,23,42,0.08)] hover:bg-muted/65 hover:text-foreground disabled:text-muted-foreground/50"
                   : isHero
-                    ? "border border-foreground bg-foreground text-background shadow-[0_4px_12px_rgba(15,23,42,0.20)] hover:bg-foreground/90 disabled:border-foreground/35 disabled:bg-foreground/35 disabled:text-background/80"
-                    : "border border-foreground bg-foreground text-background shadow-[0_3px_10px_rgba(15,23,42,0.18)] hover:bg-foreground/90 disabled:border-foreground/35 disabled:bg-foreground/35 disabled:text-background/80",
+                    ? "border border-foreground bg-foreground text-background shadow-[0_4px_12px_rgba(15,23,42,0.20)] hover:bg-foreground/90 disabled:border-foreground disabled:bg-foreground disabled:text-background"
+                    : "border border-foreground bg-foreground text-background shadow-[0_3px_10px_rgba(15,23,42,0.18)] hover:bg-foreground/90 disabled:border-foreground disabled:bg-foreground disabled:text-background",
                 isHero ? "h-8 w-8" : "h-9 w-9",
-                (canSend || showStopButton) && "hover:scale-[1.03] active:scale-95",
+                (canSend || canOpenModelSettings || showStopButton) && "hover:scale-[1.03] active:scale-95",
               )}
             >
               {showStopButton ? (
@@ -1766,44 +1788,59 @@ function ComposerModelBadge({
   label,
   provider,
   providerLabel,
+  needsSetup,
   isHero,
+  onClick,
 }: {
   label: string;
   provider?: string | null;
   providerLabel?: string | null;
+  needsSetup?: boolean;
   isHero: boolean;
+  onClick?: () => void;
 }) {
-  const inferredProvider = provider || inferProviderFromModelName(label);
+  const inferredProvider = needsSetup ? null : provider || inferProviderFromModelName(label);
   const brand = providerBrand(inferredProvider);
   const [logoIndex, setLogoIndex] = useState(0);
   const logoUrl = brand?.logoUrls[logoIndex];
   const showLogo = !!logoUrl;
   const title = providerLabel ? `${label} · ${providerLabel}` : label;
+  const interactive = Boolean(onClick);
+  const Container = interactive ? "button" : "span";
 
   useEffect(() => setLogoIndex(0), [inferredProvider]);
 
   return (
-    <span
+    <Container
       title={title}
+      type={interactive ? "button" : undefined}
+      onClick={onClick}
       className={cn(
         "inline-flex min-w-0 items-center rounded-full border border-border/55 bg-card font-medium text-foreground/82",
         "shadow-[0_2px_8px_rgba(15,23,42,0.045)]",
+        interactive && "cursor-pointer hover:bg-accent/55 hover:text-foreground",
+        needsSetup && "border-amber-500/35 bg-amber-50/70 text-amber-900 dark:bg-amber-500/10 dark:text-amber-200",
         isHero ? "h-8 max-w-[12.5rem] gap-1.5 px-2 text-[11.5px]" : "h-9 max-w-[12rem] gap-2 px-2.5 text-[12px]",
       )}
     >
       <span
-        data-testid={inferredProvider ? `composer-model-logo-${inferredProvider}` : "composer-model-logo"}
+        data-testid={needsSetup ? "composer-model-setup-icon" : inferredProvider ? `composer-model-logo-${inferredProvider}` : "composer-model-logo"}
         className={cn(
-          "grid shrink-0 place-items-center overflow-hidden rounded-full border bg-background",
+          "grid shrink-0 place-items-center overflow-hidden",
+          needsSetup
+            ? "text-amber-800 dark:text-amber-200"
+            : "rounded-full border bg-background",
           isHero ? "h-[18px] w-[18px]" : "h-5 w-5",
         )}
         style={{
-          borderColor: brand ? `${brand.color}28` : undefined,
-          boxShadow: brand ? `inset 0 0 0 1px ${brand.color}18` : undefined,
+          borderColor: !needsSetup && brand ? `${brand.color}28` : undefined,
+          boxShadow: !needsSetup && brand ? `inset 0 0 0 1px ${brand.color}18` : undefined,
         }}
         aria-hidden
       >
-        {showLogo ? (
+        {needsSetup ? (
+          <CircleHelp className={cn(isHero ? "h-3 w-3" : "h-3.5 w-3.5")} strokeWidth={1.8} />
+        ) : showLogo ? (
           <img
             src={logoUrl}
             alt=""
@@ -1825,7 +1862,7 @@ function ComposerModelBadge({
         )}
       </span>
       <span className="truncate">{label}</span>
-    </span>
+    </Container>
   );
 }
 
diff --git a/webui/src/components/thread/ThreadHeader.tsx b/webui/src/components/thread/ThreadHeader.tsx
index 8fe414a98..698344dc3 100644
--- a/webui/src/components/thread/ThreadHeader.tsx
+++ b/webui/src/components/thread/ThreadHeader.tsx
@@ -10,6 +10,7 @@ interface ThreadHeaderProps {
   theme: "light" | "dark";
   onToggleTheme: () => void;
   hideSidebarToggleForHostChrome?: boolean;
+  hostChromeTitleInset?: boolean;
   hideThemeButton?: boolean;
   minimal?: boolean;
 }
@@ -20,6 +21,7 @@ export function ThreadHeader({
   theme,
   onToggleTheme,
   hideSidebarToggleForHostChrome = false,
+  hostChromeTitleInset = false,
   hideThemeButton = false,
   minimal = false,
 }: ThreadHeaderProps) {
@@ -52,7 +54,12 @@ export function ThreadHeader({
   }
 
   return (
-    <div className="relative z-10 flex items-center justify-between gap-3 px-3 py-2">
+    <div
+      className={cn(
+        "relative z-10 flex items-center justify-between gap-3 px-3 py-2",
+        hostChromeTitleInset && "lg:pl-[128px]",
+      )}
+    >
       <div className="relative flex min-w-0 items-center gap-2">
         <Button
           variant="ghost"
diff --git a/webui/src/components/thread/ThreadMessages.tsx b/webui/src/components/thread/ThreadMessages.tsx
index b548ede26..32e405e78 100644
--- a/webui/src/components/thread/ThreadMessages.tsx
+++ b/webui/src/components/thread/ThreadMessages.tsx
@@ -14,6 +14,7 @@ interface ThreadMessagesProps {
   onLoadEarlier?: () => void;
   cliApps?: CliAppInfo[];
   mcpPresets?: McpPresetInfo[];
+  onOpenFilePreview?: (path: string) => void;
 }
 
 export type DisplayUnit = TurnUnit;
@@ -33,8 +34,13 @@ export function isFinalAssistantSliceBeforeNextUser(
   return true;
 }
 
-export function buildDisplayUnits(messages: UIMessage[]): DisplayUnit[] {
-  return normalizeActivityTimeline(messages);
+export function buildDisplayUnits(
+  messages: UIMessage[],
+  isStreaming = false,
+): DisplayUnit[] {
+  return normalizeActivityTimeline(messages, {
+    preserveTrailingActivity: isStreaming,
+  });
 }
 
 export function assistantCopyFlags(units: DisplayUnit[]): boolean[] {
@@ -61,9 +67,10 @@ export function ThreadMessages({
   onLoadEarlier,
   cliApps = [],
   mcpPresets = [],
+  onOpenFilePreview,
 }: ThreadMessagesProps) {
   const { t } = useTranslation();
-  const units = useMemo(() => buildDisplayUnits(messages), [messages]);
+  const units = useMemo(() => buildDisplayUnits(messages, isStreaming), [isStreaming, messages]);
   const copyFlags = useMemo(() => assistantCopyFlags(units), [units]);
   const liveActivityClusterIndices = useMemo(
     () => isStreaming ? currentActivityClusterIndices(units) : new Set<number>(),
@@ -117,6 +124,7 @@ export function ThreadMessages({
                 turnLatencyMs={unit.turnLatencyMs}
                 cliApps={cliApps}
                 mcpPresets={mcpPresets}
+                onOpenFilePreview={onOpenFilePreview}
               />
             ) : (
               <MessageBubble
@@ -128,6 +136,7 @@ export function ThreadMessages({
                 }
                 cliApps={cliApps}
                 mcpPresets={mcpPresets}
+                onOpenFilePreview={onOpenFilePreview}
               />
             )}
           </div>
diff --git a/webui/src/components/thread/ThreadShell.tsx b/webui/src/components/thread/ThreadShell.tsx
index 315d4cef4..c361151e7 100644
--- a/webui/src/components/thread/ThreadShell.tsx
+++ b/webui/src/components/thread/ThreadShell.tsx
@@ -1,6 +1,8 @@
 import { useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from "react";
+import type { PointerEvent as ReactPointerEvent } from "react";
 import { useTranslation } from "react-i18next";
 
+import { FilePreviewPanel } from "@/components/FilePreviewPanel";
 import { ThreadComposer } from "@/components/thread/ThreadComposer";
 import { ThreadHeader } from "@/components/thread/ThreadHeader";
 import { StreamErrorNotice } from "@/components/thread/StreamErrorNotice";
@@ -51,6 +53,23 @@ function isStaleThreadSnapshot(current: UIMessage[], snapshot: UIMessage[]): boo
   return snapshot.every((message, index) => sameMessageShape(current[index], message));
 }
 
+const FILE_PREVIEW_DEFAULT_WIDTH = 544;
+const FILE_PREVIEW_MIN_WIDTH = 360;
+const FILE_PREVIEW_MAX_WIDTH = 860;
+const FILE_PREVIEW_MIN_MAIN_WIDTH = 420;
+const FILE_PREVIEW_CLOSE_ANIMATION_MS = 320;
+
+function clampFilePreviewWidth(width: number, maxWidth: number): number {
+  return Math.min(Math.max(width, FILE_PREVIEW_MIN_WIDTH), maxWidth);
+}
+
+function maxFilePreviewWidth(containerWidth: number): number {
+  return Math.max(
+    FILE_PREVIEW_MIN_WIDTH,
+    Math.min(FILE_PREVIEW_MAX_WIDTH, containerWidth - FILE_PREVIEW_MIN_MAIN_WIDTH),
+  );
+}
+
 interface ThreadShellProps {
   session: ChatSummary | null;
   title: string;
@@ -62,6 +81,7 @@ interface ThreadShellProps {
   theme?: "light" | "dark";
   onToggleTheme?: () => void;
   hideSidebarToggleForHostChrome?: boolean;
+  hostChromeTitleInset?: boolean;
   hideThemeButton?: boolean;
   hideHeader?: boolean;
   workspaceScope?: WorkspaceScopePayload | null;
@@ -71,6 +91,7 @@ interface ThreadShellProps {
   workspaceError?: string | null;
   onWorkspaceScopeChange?: (scope: WorkspaceScopePayload) => void;
   settingsSnapshot?: SettingsPayload | null;
+  onOpenModelSettings?: () => void;
 }
 
 function toModelBadgeLabel(modelName: string | null): string | null {
@@ -85,6 +106,7 @@ interface ModelBadgeInfo {
   label: string | null;
   provider: string | null;
   providerLabel: string | null;
+  needsSetup: boolean;
 }
 
 function activeModelPreset(settings: SettingsPayload | null): SettingsPayload["model_presets"][number] | null {
@@ -107,12 +129,20 @@ function resolvedModelProvider(settings: SettingsPayload | null, modelName: stri
 }
 
 function toModelBadgeInfo(modelName: string | null, settings: SettingsPayload | null): ModelBadgeInfo {
-  const label = toModelBadgeLabel(modelName || settings?.agent.model || null);
-  const provider = resolvedModelProvider(settings, modelName || settings?.agent.model || null);
+  const model = modelName || settings?.agent.model || null;
+  const label = toModelBadgeLabel(model);
+  const provider = resolvedModelProvider(settings, model);
+  const providerRow = provider
+    ? settings?.providers.find((item) => item.name === provider)
+    : null;
+  const needsSetup = Boolean(
+    settings && (!model || !provider || !providerRow || !providerRow.configured),
+  );
   return {
     label,
     provider,
     providerLabel: provider ? providerDisplayLabel(settings?.providers ?? [], provider) : null,
+    needsSetup,
   };
 }
 
@@ -143,6 +173,7 @@ export function ThreadShell({
   theme = "light",
   onToggleTheme = () => {},
   hideSidebarToggleForHostChrome = false,
+  hostChromeTitleInset = false,
   hideThemeButton = false,
   hideHeader = false,
   workspaceScope = null,
@@ -152,6 +183,7 @@ export function ThreadShell({
   workspaceError = null,
   onWorkspaceScopeChange,
   settingsSnapshot = null,
+  onOpenModelSettings,
 }: ThreadShellProps) {
   const { t } = useTranslation();
   const chatId = session?.chatId ?? null;
@@ -171,6 +203,12 @@ export function ThreadShell({
   const [settings, setSettings] = useState<SettingsPayload | null>(settingsSnapshot);
   const [heroGreetingKey, setHeroGreetingKey] = useState(randomHeroGreetingKey);
   const [scrollToBottomSignal, setScrollToBottomSignal] = useState(0);
+  const [filePreviewPath, setFilePreviewPath] = useState<string | null>(null);
+  const [filePreviewClosing, setFilePreviewClosing] = useState(false);
+  const [filePreviewWidth, setFilePreviewWidth] = useState(FILE_PREVIEW_DEFAULT_WIDTH);
+  const shellRef = useRef<HTMLElement | null>(null);
+  const filePreviewWidthRef = useRef(FILE_PREVIEW_DEFAULT_WIDTH);
+  const filePreviewCloseTimerRef = useRef<number | null>(null);
   const pendingFirstRef = useRef<PendingFirstMessage | null>(null);
   const messageCacheRef = useRef<Map<string, UIMessage[]>>(new Map());
   /** Last chatId we associated with the in-memory thread (for cache-on-switch). */
@@ -204,6 +242,27 @@ export function ThreadShell({
     if (chatId && historyKey) sessionKeyByChatIdRef.current.set(chatId, historyKey);
   }, [chatId, historyKey]);
 
+  useEffect(() => {
+    filePreviewWidthRef.current = filePreviewWidth;
+  }, [filePreviewWidth]);
+
+  useEffect(() => {
+    if (filePreviewCloseTimerRef.current !== null) {
+      window.clearTimeout(filePreviewCloseTimerRef.current);
+      filePreviewCloseTimerRef.current = null;
+    }
+    setFilePreviewClosing(false);
+    setFilePreviewPath(null);
+  }, [historyKey]);
+
+  useEffect(() => {
+    return () => {
+      if (filePreviewCloseTimerRef.current !== null) {
+        window.clearTimeout(filePreviewCloseTimerRef.current);
+      }
+    };
+  }, []);
+
   const displayMessages = useMemo(() => projectWebuiThreadMessages(messages), [messages]);
 
   const showHeroComposer = messages.length === 0 && !loading;
@@ -212,6 +271,9 @@ export function ThreadShell({
     () => toModelBadgeInfo(modelName, settings),
     [modelName, settings],
   );
+  const modelBadgeLabel = modelBadge.needsSetup
+    ? t("thread.composer.modelNotConfigured", { defaultValue: "Model not configured" })
+    : modelBadge.label;
   useEffect(() => {
     if (showHeroComposer && !wasShowingHeroComposerRef.current) {
       setHeroGreetingKey(randomHeroGreetingKey());
@@ -482,6 +544,94 @@ export function ThreadShell({
     [send, withWorkspaceScope],
   );
 
+  const handleOpenFilePreview = useCallback((path: string) => {
+    if (filePreviewCloseTimerRef.current !== null) {
+      window.clearTimeout(filePreviewCloseTimerRef.current);
+      filePreviewCloseTimerRef.current = null;
+    }
+    setFilePreviewClosing(false);
+    setFilePreviewPath(path);
+  }, []);
+
+  const handleCloseFilePreview = useCallback(() => {
+    if (!filePreviewPath || filePreviewClosing) return;
+    setFilePreviewClosing(true);
+    filePreviewCloseTimerRef.current = window.setTimeout(() => {
+      filePreviewCloseTimerRef.current = null;
+      setFilePreviewPath(null);
+      setFilePreviewClosing(false);
+    }, FILE_PREVIEW_CLOSE_ANIMATION_MS);
+  }, [filePreviewClosing, filePreviewPath]);
+
+  const handleFilePreviewResizeStart = useCallback((event: ReactPointerEvent<HTMLButtonElement>) => {
+    event.preventDefault();
+    event.stopPropagation();
+    const panel = event.currentTarget.closest<HTMLElement>("[data-file-preview-panel]");
+    const shellRect = shellRef.current?.getBoundingClientRect();
+    const rightEdge = shellRect?.right ?? window.innerWidth;
+    const maxWidth = maxFilePreviewWidth(shellRect?.width ?? window.innerWidth);
+    const originalBodyCursor = document.body.style.cursor;
+    const originalBodyUserSelect = document.body.style.userSelect;
+    const originalPanelTransition = panel?.style.transition ?? "";
+    let nextWidth = filePreviewWidthRef.current;
+    let frame: number | null = null;
+
+    document.body.style.cursor = "col-resize";
+    document.body.style.userSelect = "none";
+    if (panel) panel.style.transition = "none";
+
+    const applyWidth = (clientX: number) => {
+      nextWidth = clampFilePreviewWidth(rightEdge - clientX, maxWidth);
+      filePreviewWidthRef.current = nextWidth;
+      if (frame !== null) return;
+      frame = window.requestAnimationFrame(() => {
+        frame = null;
+        panel?.style.setProperty("--file-preview-width", `${nextWidth}px`);
+        panel?.style.setProperty("--file-preview-slot-width", `${nextWidth}px`);
+      });
+    };
+    const handlePointerMove = (moveEvent: PointerEvent) => {
+      moveEvent.preventDefault();
+      applyWidth(moveEvent.clientX);
+    };
+    const handlePointerUp = () => {
+      if (frame !== null) {
+        window.cancelAnimationFrame(frame);
+        frame = null;
+      }
+      panel?.style.setProperty("--file-preview-width", `${nextWidth}px`);
+      panel?.style.setProperty("--file-preview-slot-width", `${nextWidth}px`);
+      if (panel) panel.style.transition = originalPanelTransition;
+      setFilePreviewWidth(nextWidth);
+      document.body.style.cursor = originalBodyCursor;
+      document.body.style.userSelect = originalBodyUserSelect;
+      window.removeEventListener("pointermove", handlePointerMove);
+      window.removeEventListener("pointerup", handlePointerUp);
+      window.removeEventListener("pointercancel", handlePointerUp);
+    };
+
+    applyWidth(event.clientX);
+    window.addEventListener("pointermove", handlePointerMove);
+    window.addEventListener("pointerup", handlePointerUp);
+    window.addEventListener("pointercancel", handlePointerUp);
+  }, []);
+
+  useEffect(() => {
+    if (!filePreviewPath) return;
+    const clampToShell = () => {
+      const shellWidth = shellRef.current?.getBoundingClientRect().width ?? window.innerWidth;
+      const maxWidth = maxFilePreviewWidth(shellWidth);
+      const nextWidth = clampFilePreviewWidth(filePreviewWidthRef.current, maxWidth);
+      filePreviewWidthRef.current = nextWidth;
+      setFilePreviewWidth(nextWidth);
+    };
+    clampToShell();
+    window.addEventListener("resize", clampToShell);
+    return () => {
+      window.removeEventListener("resize", clampToShell);
+    };
+  }, [filePreviewPath]);
+
   const composer = (
     <>
       {streamError ? (
@@ -500,9 +650,11 @@ export function ThreadShell({
               ? t("thread.composer.placeholderHero")
               : t("thread.composer.placeholderThread")
           }
-          modelLabel={modelBadge.label}
+          modelLabel={modelBadgeLabel}
           modelProvider={modelBadge.provider}
           modelProviderLabel={modelBadge.providerLabel}
+          modelNeedsSetup={modelBadge.needsSetup}
+          onModelBadgeClick={modelBadge.needsSetup ? onOpenModelSettings : undefined}
           variant={showHeroComposer ? "hero" : "thread"}
           slashCommands={slashCommands}
           cliApps={cliApps}
@@ -528,9 +680,11 @@ export function ThreadShell({
               ? t("thread.composer.placeholderOpening")
               : t("thread.composer.placeholderHero")
           }
-          modelLabel={modelBadge.label}
+          modelLabel={modelBadgeLabel}
           modelProvider={modelBadge.provider}
           modelProviderLabel={modelBadge.providerLabel}
+          modelNeedsSetup={modelBadge.needsSetup}
+          onModelBadgeClick={modelBadge.needsSetup ? onOpenModelSettings : undefined}
           variant="hero"
           slashCommands={slashCommands}
           cliApps={cliApps}
@@ -561,29 +715,44 @@ export function ThreadShell({
   );
 
   return (
-    <section className="relative flex min-h-0 flex-1 flex-col overflow-hidden">
-      {!hideHeader ? (
-        <ThreadHeader
-          title={title}
-          onToggleSidebar={onToggleSidebar}
-          theme={theme}
-          onToggleTheme={onToggleTheme}
-          hideSidebarToggleForHostChrome={hideSidebarToggleForHostChrome}
-          hideThemeButton={hideThemeButton}
-          minimal={!session && !loading}
+    <section ref={shellRef} className="relative flex min-h-0 flex-1 overflow-hidden">
+      <div className="relative flex min-w-0 flex-1 flex-col overflow-hidden">
+        {!hideHeader ? (
+          <ThreadHeader
+            title={title}
+            onToggleSidebar={onToggleSidebar}
+            theme={theme}
+            onToggleTheme={onToggleTheme}
+            hideSidebarToggleForHostChrome={hideSidebarToggleForHostChrome}
+            hostChromeTitleInset={hostChromeTitleInset}
+            hideThemeButton={hideThemeButton}
+            minimal={!session && !loading}
+          />
+        ) : null}
+        <ThreadViewport
+          messages={displayMessages}
+          isStreaming={isStreaming}
+          emptyState={emptyState}
+          composer={composer}
+          scrollToBottomSignal={scrollToBottomSignal}
+          conversationKey={historyKey}
+          showScrollToBottomButton={!!session}
+          cliApps={cliApps}
+          mcpPresets={mcpPresets}
+          onOpenFilePreview={historyKey ? handleOpenFilePreview : undefined}
+        />
+      </div>
+      {filePreviewPath && historyKey ? (
+        <FilePreviewPanel
+          sessionKey={historyKey}
+          path={filePreviewPath}
+          token={token}
+          desktopWidth={filePreviewWidth}
+          isClosing={filePreviewClosing}
+          onResizeStart={handleFilePreviewResizeStart}
+          onClose={handleCloseFilePreview}
         />
       ) : null}
-      <ThreadViewport
-        messages={displayMessages}
-        isStreaming={isStreaming}
-        emptyState={emptyState}
-        composer={composer}
-        scrollToBottomSignal={scrollToBottomSignal}
-        conversationKey={historyKey}
-        showScrollToBottomButton={!!session}
-        cliApps={cliApps}
-        mcpPresets={mcpPresets}
-      />
     </section>
   );
 }
diff --git a/webui/src/components/thread/ThreadViewport.tsx b/webui/src/components/thread/ThreadViewport.tsx
index 26a0c66c8..36a261af4 100644
--- a/webui/src/components/thread/ThreadViewport.tsx
+++ b/webui/src/components/thread/ThreadViewport.tsx
@@ -27,6 +27,7 @@ interface ThreadViewportProps {
   showScrollToBottomButton?: boolean;
   cliApps?: CliAppInfo[];
   mcpPresets?: McpPresetInfo[];
+  onOpenFilePreview?: (path: string) => void;
 }
 
 const NEAR_BOTTOM_PX = 48;
@@ -58,6 +59,7 @@ export function ThreadViewport({
   showScrollToBottomButton = true,
   cliApps = [],
   mcpPresets = [],
+  onOpenFilePreview,
 }: ThreadViewportProps) {
   const { t } = useTranslation();
   const scrollRef = useRef<HTMLDivElement>(null);
@@ -256,6 +258,7 @@ export function ThreadViewport({
                   onLoadEarlier={loadEarlierMessages}
                   cliApps={cliApps}
                   mcpPresets={mcpPresets}
+                  onOpenFilePreview={onOpenFilePreview}
                 />
               </div>
             </div>
diff --git a/webui/src/components/thread/WorkspaceControls.tsx b/webui/src/components/thread/WorkspaceControls.tsx
index 8188722a6..8c80ac249 100644
--- a/webui/src/components/thread/WorkspaceControls.tsx
+++ b/webui/src/components/thread/WorkspaceControls.tsx
@@ -106,7 +106,7 @@ export function WorkspaceProjectPicker({
 
   if (nativeProjectPicker) {
     return (
-      <div className="flex items-center border-t border-border/25 bg-muted/60 px-4 py-1.5 dark:bg-white/[0.055]">
+      <div className="flex items-center rounded-b-[28px] border-t border-border/25 bg-muted/60 px-4 py-1.5 dark:bg-white/[0.055]">
         <button
           type="button"
           disabled={disabled || pickingFolder}
@@ -133,7 +133,7 @@ export function WorkspaceProjectPicker({
   }
 
   return (
-    <div className="flex items-center border-t border-border/25 bg-muted/60 px-4 py-1.5 dark:bg-white/[0.055]">
+    <div className="flex items-center rounded-b-[28px] border-t border-border/25 bg-muted/60 px-4 py-1.5 dark:bg-white/[0.055]">
       <DropdownMenu open={open} onOpenChange={setOpen}>
         <DropdownMenuTrigger asChild>
           <button
diff --git a/webui/src/components/thread/activity/FileEditRow.tsx b/webui/src/components/thread/activity/FileEditRow.tsx
index 8e67333ef..2d9e2e631 100644
--- a/webui/src/components/thread/activity/FileEditRow.tsx
+++ b/webui/src/components/thread/activity/FileEditRow.tsx
@@ -22,18 +22,34 @@ export interface FileEditSummary {
   error?: string;
 }
 
-export function FileEditGroup({ edits }: { edits: FileEditSummary[] }) {
+export function FileEditGroup({
+  edits,
+  onOpenFilePreview,
+}: {
+  edits: FileEditSummary[];
+  onOpenFilePreview?: (path: string) => void;
+}) {
   if (edits.length === 0) return null;
   return (
     <ul className="space-y-1">
       {edits.map((edit) => (
-        <FileEditRow key={edit.key} edit={edit} />
+        <FileEditRow
+          key={edit.key}
+          edit={edit}
+          onOpenFilePreview={onOpenFilePreview}
+        />
       ))}
     </ul>
   );
 }
 
-function FileEditRow({ edit }: { edit: FileEditSummary }) {
+function FileEditRow({
+  edit,
+  onOpenFilePreview,
+}: {
+  edit: FileEditSummary;
+  onOpenFilePreview?: (path: string) => void;
+}) {
   const { t } = useTranslation();
   const editing = edit.status === "editing";
   const failed = edit.status === "error";
@@ -76,6 +92,8 @@ function FileEditRow({ edit }: { edit: FileEditSummary }) {
           <FileReferenceChip
             path={edit.path}
             tooltipPath={edit.absolute_path}
+            previewPath={edit.absolute_path || edit.path}
+            onOpen={onOpenFilePreview}
             display="path"
             active={editing}
             className="min-w-0"
diff --git a/webui/src/components/thread/activity/ReasoningRow.tsx b/webui/src/components/thread/activity/ReasoningRow.tsx
index 6ed067e68..7862e2afa 100644
--- a/webui/src/components/thread/activity/ReasoningRow.tsx
+++ b/webui/src/components/thread/activity/ReasoningRow.tsx
@@ -10,9 +10,11 @@ import { ActivityStep } from "./ActivityStep";
 export function ReasoningRow({
   text,
   streaming,
+  onOpenFilePreview,
 }: {
   text: string;
   streaming: boolean;
+  onOpenFilePreview?: (path: string) => void;
 }) {
   const { t } = useTranslation();
   useEffect(() => {
@@ -30,6 +32,7 @@ export function ReasoningRow({
       {text.trim() ? (
         <MarkdownText
           streaming={streaming}
+          onOpenFilePreview={onOpenFilePreview}
           className={cn(
             "min-w-0 text-[12.5px] italic text-muted-foreground/78",
             "prose-p:my-1 prose-li:my-0.5",
diff --git a/webui/src/globals.css b/webui/src/globals.css
index e6a2af90f..f25f62d13 100644
--- a/webui/src/globals.css
+++ b/webui/src/globals.css
@@ -121,10 +121,13 @@
   }
 
   .host-sidebar-glass {
+    background: hsl(var(--sidebar) / 0.94);
+    -webkit-backdrop-filter: saturate(145%) blur(18px);
+    backdrop-filter: saturate(145%) blur(18px);
     box-shadow:
-      inset -1px 0 0 hsl(var(--border) / 0.36),
-      inset 1px 0 0 hsl(var(--background) / 0.34),
-      18px 0 44px -42px rgb(0 0 0 / 0.42);
+      inset -1px 0 0 hsl(var(--border) / 0.32),
+      inset 1px 0 0 hsl(var(--background) / 0.52),
+      14px 0 32px -30px rgb(0 0 0 / 0.22);
   }
 
   .dark .host-window-shell,
@@ -135,10 +138,11 @@
   }
 
   .dark .host-sidebar-glass {
+    background: hsl(var(--sidebar) / 0.96);
     box-shadow:
       inset -1px 0 0 hsl(var(--border) / 0.42),
       inset 1px 0 0 hsl(var(--foreground) / 0.05),
-      18px 0 46px -42px rgb(0 0 0 / 0.72);
+      14px 0 34px -30px rgb(0 0 0 / 0.62);
   }
 
   @supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
diff --git a/webui/src/hooks/useNanobotStream.ts b/webui/src/hooks/useNanobotStream.ts
index 790e96bb4..182dddbd5 100644
--- a/webui/src/hooks/useNanobotStream.ts
+++ b/webui/src/hooks/useNanobotStream.ts
@@ -20,6 +20,7 @@ import type {
   UIImage,
   UIFileEdit,
   UIMessage,
+  UITurnPhase,
   WorkspaceScopePayload,
 } from "@/lib/types";
 
@@ -34,22 +35,50 @@ interface ActiveAssistantCursor {
 }
 
 type PendingStreamEvent =
-  | { kind: "delta"; text: string }
-  | { kind: "reasoning"; text: string };
+  | { kind: "delta"; text: string; turn: UIMessageTurnFields }
+  | { kind: "reasoning"; text: string; turn: UIMessageTurnFields };
+
+type UIMessageTurnFields = Pick<UIMessage, "turnId" | "turnPhase" | "turnSeq">;
 
 const FILE_EDIT_TOOL_NAMES = new Set(["write_file", "edit_file", "apply_patch"]);
 
+function turnFieldsFromEvent(
+  ev: { turn_id?: string; turn_phase?: UITurnPhase; turn_seq?: number },
+  fallbackPhase?: UITurnPhase,
+): UIMessageTurnFields {
+  const fields: UIMessageTurnFields = {};
+  if (typeof ev.turn_id === "string" && ev.turn_id.length > 0) {
+    fields.turnId = ev.turn_id;
+  }
+  const phase = ev.turn_phase ?? fallbackPhase;
+  if (phase) fields.turnPhase = phase;
+  if (typeof ev.turn_seq === "number" && Number.isFinite(ev.turn_seq)) {
+    fields.turnSeq = ev.turn_seq;
+  }
+  return fields;
+}
+
+function matchesTurn(message: UIMessage, turn: UIMessageTurnFields): boolean {
+  return !turn.turnId || !message.turnId || message.turnId === turn.turnId;
+}
+
 /** Find a still-open streamed assistant turn. Closed stream segments stay visible
  * as streaming until ``turn_end`` for visual continuity, but they must not
  * receive later delta segments. */
 function findStreamingAssistantIndex(
   prev: UIMessage[],
   closedStreamIds: ReadonlySet<string>,
+  turn: UIMessageTurnFields = {},
 ): number | null {
   for (let i = prev.length - 1; i >= 0; i -= 1) {
     const m = prev[i];
     if (m.kind === "trace") continue;
-    if (m.role === "assistant" && m.isStreaming && !closedStreamIds.has(m.id)) return i;
+    if (
+      m.role === "assistant"
+      && m.isStreaming
+      && !closedStreamIds.has(m.id)
+      && matchesTurn(m, turn)
+    ) return i;
     if (m.role === "user") break;
   }
   return null;
@@ -69,6 +98,7 @@ function attachReasoningChunk(
   segments?: {
     ensure: () => string;
   },
+  turn: UIMessageTurnFields = {},
 ): UIMessage[] {
   for (let i = prev.length - 1; i >= 0; i -= 1) {
     const candidate = prev[i];
@@ -80,6 +110,7 @@ function attachReasoningChunk(
     // that produced those tool calls.
     if (candidate.kind === "trace") break;
     if (candidate.role !== "assistant") continue;
+    if (!matchesTurn(candidate, turn)) break;
     const activitySegmentId = candidate.activitySegmentId ?? segments?.ensure();
     const hasAnswer = candidate.content.length > 0;
     if (hasAnswer) break;
@@ -93,6 +124,7 @@ function attachReasoningChunk(
         reasoning: (candidate.reasoning ?? "") + chunk,
         reasoningStreaming: true,
         ...(activitySegmentId ? { activitySegmentId } : {}),
+        ...turn,
       };
       return [...prev.slice(0, i), merged, ...prev.slice(i + 1)];
     }
@@ -109,6 +141,7 @@ function attachReasoningChunk(
       reasoning: chunk,
       reasoningStreaming: true,
       ...(activitySegmentId ? { activitySegmentId } : {}),
+      ...turn,
       createdAt: Date.now(),
     },
   ];
@@ -122,12 +155,16 @@ function attachReasoningChunk(
  * the model already produced an answer in a previous turn, so the new
  * delta belongs in a fresh row.
  */
-function findActiveAssistantPlaceholderIndex(prev: UIMessage[]): number | null {
+function findActiveAssistantPlaceholderIndex(
+  prev: UIMessage[],
+  turn: UIMessageTurnFields = {},
+): number | null {
   const last = prev[prev.length - 1];
   if (!last) return null;
   if (last.role !== "assistant" || last.kind === "trace") return null;
   if (last.content.length > 0) return null;
   if (!last.isStreaming) return null;
+  if (!matchesTurn(last, turn)) return null;
   return prev.length - 1;
 }
 
@@ -187,10 +224,18 @@ function pruneReasoningOnlyPlaceholders(prev: UIMessage[]): UIMessage[] {
   });
 }
 
-function stampLastAssistantLatency(prev: UIMessage[], latencyMs: number): UIMessage[] {
+function stampLastAssistantLatency(
+  prev: UIMessage[],
+  latencyMs: number,
+  turnId?: string,
+): UIMessage[] {
   for (let i = prev.length - 1; i >= 0; i -= 1) {
     const m = prev[i];
-    if (m.role === "assistant" && m.kind !== "trace") {
+    if (
+      m.role === "assistant"
+      && m.kind !== "trace"
+      && (!turnId || !m.turnId || m.turnId === turnId)
+    ) {
       const merged: UIMessage = { ...m, latencyMs, isStreaming: false };
       return [...prev.slice(0, i), merged, ...prev.slice(i + 1)];
     }
@@ -203,7 +248,7 @@ function absorbCompleteAssistantMessage(
   message: Omit<UIMessage, "id" | "role" | "createdAt">,
 ): UIMessage[] {
   const last = prev[prev.length - 1];
-  if (!last || !isReasoningOnlyPlaceholder(last)) {
+  if (!last || !isReasoningOnlyPlaceholder(last) || !matchesTurn(last, message)) {
     return [
       ...prev,
       {
@@ -482,7 +527,10 @@ export function useNanobotStream(
     return !!closedStreamId;
   }, []);
 
-  const resolveActiveAssistantIndex = useCallback((prev: UIMessage[]): number | null => {
+  const resolveActiveAssistantIndex = useCallback((
+    prev: UIMessage[],
+    turn: UIMessageTurnFields = {},
+  ): number | null => {
     const cursor = activeAssistantRef.current;
     if (!cursor) return null;
     const indexed = prev[cursor.index];
@@ -491,6 +539,7 @@ export function useNanobotStream(
       && indexed.role === "assistant"
       && indexed.kind !== "trace"
       && indexed.isStreaming
+      && matchesTurn(indexed, turn)
     ) {
       return cursor.index;
     }
@@ -500,7 +549,12 @@ export function useNanobotStream(
       return null;
     }
     const found = prev[idx];
-    if (found.role !== "assistant" || found.kind === "trace" || !found.isStreaming) {
+    if (
+      found.role !== "assistant"
+      || found.kind === "trace"
+      || !found.isStreaming
+      || !matchesTurn(found, turn)
+    ) {
       activeAssistantRef.current = null;
       return null;
     }
@@ -509,15 +563,15 @@ export function useNanobotStream(
   }, []);
 
   const appendAnswerChunk = useCallback(
-    (prev: UIMessage[], chunk: string): UIMessage[] => {
+    (prev: UIMessage[], chunk: string, turn: UIMessageTurnFields = {}): UIMessage[] => {
       let next = prev;
-      let targetIndex = resolveActiveAssistantIndex(next);
+      let targetIndex = resolveActiveAssistantIndex(next, turn);
 
       if (targetIndex === null) {
-        targetIndex = findActiveAssistantPlaceholderIndex(next);
+        targetIndex = findActiveAssistantPlaceholderIndex(next, turn);
       }
       if (targetIndex === null) {
-        targetIndex = findStreamingAssistantIndex(next, closedAssistantStreamIdsRef.current);
+        targetIndex = findStreamingAssistantIndex(next, closedAssistantStreamIdsRef.current, turn);
       }
       if (targetIndex === null) {
         const id = crypto.randomUUID();
@@ -539,6 +593,7 @@ export function useNanobotStream(
         ...target,
         content: target.content + chunk,
         isStreaming: true,
+        ...turn,
       };
       closedAssistantStreamIdsRef.current.delete(merged.id);
       activeAssistantRef.current = { id: merged.id, index: targetIndex };
@@ -551,20 +606,17 @@ export function useNanobotStream(
   const applyPendingStreamEvents = useCallback(
     (prev: UIMessage[], events: PendingStreamEvent[]): UIMessage[] => {
       let next = prev;
-      for (let i = 0; i < events.length;) {
-        const kind = events[i].kind;
-        let text = "";
-        while (i < events.length && events[i].kind === kind) {
-          text += events[i].text;
-          i += 1;
-        }
-        if (kind === "delta") {
-          next = appendAnswerChunk(next, text);
+      for (const event of events) {
+        if (event.kind === "delta") {
+          next = appendAnswerChunk(next, event.text, event.turn);
         } else {
           if (closeActiveAssistantStream()) clearActivitySegment();
-          next = attachReasoningChunk(next, text, {
-            ensure: ensureActivitySegmentId,
-          });
+          next = attachReasoningChunk(
+            next,
+            event.text,
+            { ensure: ensureActivitySegmentId },
+            event.turn,
+          );
         }
       }
       return next;
@@ -575,6 +627,7 @@ export function useNanobotStream(
   const flushPendingStreamEvents = useCallback((options?: {
     closeAnswerSegment?: boolean;
     finalAnswerText?: string;
+    turn?: UIMessageTurnFields;
   }) => {
     if (streamFrameRef.current !== null) {
       window.cancelAnimationFrame(streamFrameRef.current);
@@ -582,6 +635,7 @@ export function useNanobotStream(
     }
     const events = pendingStreamEventsRef.current;
     const finalAnswerText = options?.finalAnswerText;
+    const turn = options?.turn ?? {};
     if (events.length === 0 && finalAnswerText === undefined) {
       if (options?.closeAnswerSegment) closeActiveAssistantStream();
       return;
@@ -591,14 +645,15 @@ export function useNanobotStream(
       let next = events.length > 0 ? applyPendingStreamEvents(prev, events) : prev;
       if (finalAnswerText !== undefined) {
         const targetIndex =
-          resolveActiveAssistantIndex(next)
-          ?? findStreamingAssistantIndex(next, closedAssistantStreamIdsRef.current);
+          resolveActiveAssistantIndex(next, turn)
+          ?? findStreamingAssistantIndex(next, closedAssistantStreamIdsRef.current, turn);
           if (targetIndex !== null) {
             const target = next[targetIndex];
             next = replaceMessageAt(next, targetIndex, {
               ...target,
               content: finalAnswerText,
               isStreaming: true,
+              ...turn,
             });
           } else {
             const id = crypto.randomUUID();
@@ -610,6 +665,7 @@ export function useNanobotStream(
                 role: "assistant",
                 content: finalAnswerText,
                 isStreaming: true,
+                ...turn,
                 createdAt: Date.now(),
               },
             ];
@@ -679,7 +735,11 @@ export function useNanobotStream(
         if (!chunk) return;
         clearActivitySegment();
         setIsStreaming(true);
-        pendingStreamEventsRef.current.push({ kind: "delta", text: chunk });
+        pendingStreamEventsRef.current.push({
+          kind: "delta",
+          text: chunk,
+          turn: turnFieldsFromEvent(ev, "answer"),
+        });
         schedulePendingStreamFlush();
         return;
       }
@@ -690,7 +750,11 @@ export function useNanobotStream(
         if (!chunk) return;
         if (fileEditSegmentRef.current) clearActivitySegment();
         setIsStreaming(true);
-        pendingStreamEventsRef.current.push({ kind: "reasoning", text: chunk });
+        pendingStreamEventsRef.current.push({
+          kind: "reasoning",
+          text: chunk,
+          turn: turnFieldsFromEvent(ev, "reasoning"),
+        });
         schedulePendingStreamFlush();
         return;
       }
@@ -699,6 +763,7 @@ export function useNanobotStream(
         flushPendingStreamEvents({
           closeAnswerSegment: true,
           ...(typeof ev.text === "string" ? { finalAnswerText: ev.text } : {}),
+          turn: turnFieldsFromEvent(ev, "answer"),
         });
         if (suppressStreamUntilTurnEndRef.current) return;
         // stream_end only means the text segment finished — the model may
@@ -751,7 +816,11 @@ export function useNanobotStream(
           let finalized = prev.map((m) => (m.isStreaming ? { ...m, isStreaming: false } : m));
           finalized = pruneReasoningOnlyPlaceholders(finalized);
           if (typeof ev.latency_ms === "number" && ev.latency_ms >= 0) {
-            finalized = stampLastAssistantLatency(finalized, Math.round(ev.latency_ms));
+            finalized = stampLastAssistantLatency(
+              finalized,
+              Math.round(ev.latency_ms),
+              ev.turn_id,
+            );
           }
           buffer.current = null;
           activeAssistantRef.current = null;
@@ -778,9 +847,12 @@ export function useNanobotStream(
           const line = ev.text;
           if (!line) return;
           if (fileEditSegmentRef.current) clearActivitySegment();
-          setMessages((prev) => closeReasoningStream(attachReasoningChunk(prev, line, {
-            ensure: ensureActivitySegmentId,
-          })));
+          setMessages((prev) => closeReasoningStream(attachReasoningChunk(
+            prev,
+            line,
+            { ensure: ensureActivitySegmentId },
+            turnFieldsFromEvent(ev, "reasoning"),
+          )));
           return;
         }
         // Intermediate agent breadcrumbs (tool-call hints, raw progress).
@@ -788,6 +860,7 @@ export function useNanobotStream(
         // so a sequence of calls collapses into one compact trace group.
         if (ev.kind === "tool_hint" || ev.kind === "progress") {
           const structuredEvents = normalizeToolProgressEvents(ev.tool_events);
+          const turn = turnFieldsFromEvent(ev, "activity");
           setMessages((prev) => {
             const segmentId = ensureActivitySegmentId();
             const base = prev;
@@ -826,6 +899,7 @@ export function useNanobotStream(
                   ? mergeToolProgressEvents(last.toolEvents, visibleStructuredEvents)
                   : last.toolEvents,
                 activitySegmentId: last.activitySegmentId ?? segmentId,
+                ...turn,
               };
               return [...base.slice(0, -1), merged];
             }
@@ -839,6 +913,7 @@ export function useNanobotStream(
                 traces: lines,
                 ...(visibleStructuredEvents.length ? { toolEvents: visibleStructuredEvents } : {}),
                 activitySegmentId: segmentId,
+                ...turn,
                 createdAt: Date.now(),
               },
             ];
@@ -870,6 +945,7 @@ export function useNanobotStream(
             content,
             ...(hasMedia ? { media } : {}),
             ...(lat !== undefined ? { latencyMs: lat } : {}),
+            ...turnFieldsFromEvent(ev, "answer"),
           });
         });
         if (hasMedia) {
@@ -882,6 +958,7 @@ export function useNanobotStream(
         if (edits.length === 0) return;
         const normalized = mergeFileEdits(undefined, edits);
         if (normalized.length === 0) return;
+        const turn = turnFieldsFromEvent(ev, "activity");
         const opensFileEditPhase = normalized.some(
           (edit) => edit.status === "editing" || edit.phase === "start",
         );
@@ -903,6 +980,7 @@ export function useNanobotStream(
               ...cleanedTarget,
               fileEdits: mergeFileEdits(cleanedTarget.fileEdits, normalized),
               activitySegmentId: segmentId,
+              ...turn,
             };
             return replaceMessageAt(base, targetIndex, merged);
           }
@@ -918,6 +996,7 @@ export function useNanobotStream(
               traces: [],
               fileEdits: normalized,
               activitySegmentId: segmentId,
+              ...turn,
               createdAt: Date.now(),
             },
           ];
@@ -962,6 +1041,7 @@ export function useNanobotStream(
       if (!hasImages && !content.trim()) return;
 
       flushPendingStreamEvents();
+      const turnId = crypto.randomUUID();
       const previews = hasImages ? images!.map((i) => i.preview) : undefined;
       setMessages((prev) => {
         buffer.current = null;
@@ -974,6 +1054,9 @@ export function useNanobotStream(
             id: crypto.randomUUID(),
             role: "user",
             content,
+            turnId,
+            turnPhase: "user",
+            turnSeq: 0,
             createdAt: Date.now(),
             ...(previews ? { images: previews } : {}),
             ...(options?.cliApps?.length ? { cliApps: options.cliApps } : {}),
@@ -985,11 +1068,7 @@ export function useNanobotStream(
       // right away, before the first delta arrives from the server.
       setIsStreaming(true);
       const wireMedia = hasImages ? images!.map((i) => i.media) : undefined;
-      if (options) {
-        client.sendMessage(chatId, content, wireMedia, options);
-      } else {
-        client.sendMessage(chatId, content, wireMedia);
-      }
+      client.sendMessage(chatId, content, wireMedia, { ...options, turnId });
     },
     [chatId, clearActivitySegment, client, flushPendingStreamEvents],
   );
diff --git a/webui/src/i18n/locales/en/common.json b/webui/src/i18n/locales/en/common.json
index bb0820dbf..bc823c583 100644
--- a/webui/src/i18n/locales/en/common.json
+++ b/webui/src/i18n/locales/en/common.json
@@ -295,6 +295,9 @@
       "disabled": "Disabled",
       "restartPending": "Restart pending",
       "ready": "Ready",
+      "privateEngine": "Private engine",
+      "unixSocket": "Unix socket",
+      "defaultWorkspace": "Default workspace",
       "comfortable": "Comfortable",
       "compact": "Compact",
       "auto": "Auto",
@@ -386,6 +389,31 @@
       "imageGeneration": "Image generation",
       "workspace": "Workspace"
     },
+    "usage": {
+      "title": "Token activity",
+      "shortTitle": "Token Usage",
+      "subtitle": "Provider-reported usage over the last 12 months.",
+      "empty": "Token activity will appear after new model replies.",
+      "totalTokens": "Total tokens",
+      "peakTokens": "Peak tokens",
+      "thirtyDayTokens": "30-day tokens",
+      "currentStreak": "Current streak",
+      "longestStreak": "Longest streak",
+      "daysValue": "{{count}}d",
+      "last30": "30 days",
+      "activeDays": "Active days",
+      "requests": "Requests",
+      "estimated": "estimated",
+      "includesEstimates": "includes estimates",
+      "cellTitle": "{{date}}: {{tokens}} tokens, {{requests}} requests",
+      "sources": {
+        "user": "Chat",
+        "api": "API",
+        "cron": "Automations",
+        "dream": "Memory",
+        "system": "System"
+      }
+    },
     "providers": {
       "searchPlaceholder": "Search providers",
       "noMatches": "No providers match this search.",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "Close goal",
       "send": "Send message",
       "stop": "Stop response",
+      "modelNotConfigured": "Model not configured",
+      "configureModel": "Configure model",
       "queued": {
         "label": "Queued guidance",
         "guide": "Guide",
@@ -733,6 +763,15 @@
     "next": "Next image",
     "close": "Close image preview"
   },
+  "filePreview": {
+    "aria": "File preview",
+    "close": "Close file preview",
+    "loading": "Loading preview...",
+    "failed": "Could not preview this file.",
+    "routeMissing": "File preview needs the latest gateway. Restart nanobot gateway and try again.",
+    "resize": "Resize file preview",
+    "truncated": "Preview is truncated because this file is large."
+  },
   "code": {
     "fallbackLanguage": "code",
     "copyAria": "Copy code",
diff --git a/webui/src/i18n/locales/es/common.json b/webui/src/i18n/locales/es/common.json
index 6b234aae1..949fad825 100644
--- a/webui/src/i18n/locales/es/common.json
+++ b/webui/src/i18n/locales/es/common.json
@@ -187,6 +187,9 @@
       "disabled": "Desactivado",
       "restartPending": "Reinicio pendiente",
       "ready": "Listo",
+      "privateEngine": "Motor privado",
+      "unixSocket": "Socket Unix",
+      "defaultWorkspace": "Espacio predeterminado",
       "comfortable": "Cómodo",
       "compact": "Compacto",
       "auto": "Automático",
@@ -278,6 +281,31 @@
       "imageGeneration": "Generación de imágenes",
       "workspace": "Espacio de trabajo"
     },
+    "usage": {
+      "title": "Actividad de tokens",
+      "shortTitle": "Token Usage",
+      "subtitle": "Uso reportado por el proveedor durante los últimos 12 meses.",
+      "empty": "La actividad de tokens aparecerá después de nuevas respuestas del modelo.",
+      "totalTokens": "Tokens totales",
+      "peakTokens": "Pico de tokens",
+      "thirtyDayTokens": "Tokens en 30 días",
+      "currentStreak": "Racha actual",
+      "longestStreak": "Racha más larga",
+      "daysValue": "{{count}} d",
+      "last30": "30 días",
+      "activeDays": "Días activos",
+      "requests": "Solicitudes",
+      "estimated": "estimado",
+      "includesEstimates": "incluye estimaciones",
+      "cellTitle": "{{date}}: {{tokens}} tokens, {{requests}} solicitudes",
+      "sources": {
+        "user": "Chat",
+        "api": "API",
+        "cron": "Automatizaciones",
+        "dream": "Memoria",
+        "system": "Sistema"
+      }
+    },
     "providers": {
       "searchPlaceholder": "Buscar proveedores",
       "noMatches": "Ningún proveedor coincide con esta búsqueda.",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "Cerrar objetivo",
       "send": "Enviar mensaje",
       "stop": "Detener respuesta",
+      "modelNotConfigured": "Modelo no configurado",
+      "configureModel": "Configurar modelo",
       "queued": {
         "label": "Guía en cola",
         "guide": "Guiar",
@@ -733,6 +763,15 @@
     "next": "Imagen siguiente",
     "close": "Cerrar vista previa"
   },
+  "filePreview": {
+    "aria": "Vista previa de archivo",
+    "close": "Cerrar vista previa de archivo",
+    "loading": "Cargando vista previa...",
+    "failed": "No se pudo previsualizar este archivo.",
+    "routeMissing": "La vista previa necesita el gateway más reciente. Reinicia nanobot gateway e inténtalo de nuevo.",
+    "resize": "Cambiar el tamaño de la vista previa",
+    "truncated": "La vista previa está truncada porque el archivo es grande."
+  },
   "code": {
     "fallbackLanguage": "código",
     "copyAria": "Copiar código",
diff --git a/webui/src/i18n/locales/fr/common.json b/webui/src/i18n/locales/fr/common.json
index b124c48e2..591cbd21b 100644
--- a/webui/src/i18n/locales/fr/common.json
+++ b/webui/src/i18n/locales/fr/common.json
@@ -187,6 +187,9 @@
       "disabled": "Désactivé",
       "restartPending": "Redémarrage en attente",
       "ready": "Prêt",
+      "privateEngine": "Moteur privé",
+      "unixSocket": "Socket Unix",
+      "defaultWorkspace": "Espace par défaut",
       "comfortable": "Confortable",
       "compact": "Compacte",
       "auto": "Automatique",
@@ -278,6 +281,31 @@
       "imageGeneration": "Génération d’images",
       "workspace": "Espace de travail"
     },
+    "usage": {
+      "title": "Activité des tokens",
+      "shortTitle": "Token Usage",
+      "subtitle": "Usage signalé par le fournisseur sur les 12 derniers mois.",
+      "empty": "L’activité des tokens apparaîtra après les nouvelles réponses du modèle.",
+      "totalTokens": "Tokens cumulés",
+      "peakTokens": "Pic de tokens",
+      "thirtyDayTokens": "Tokens sur 30 jours",
+      "currentStreak": "Série actuelle",
+      "longestStreak": "Plus longue série",
+      "daysValue": "{{count}} j",
+      "last30": "30 jours",
+      "activeDays": "Jours actifs",
+      "requests": "Requêtes",
+      "estimated": "estimé",
+      "includesEstimates": "inclut des estimations",
+      "cellTitle": "{{date}} : {{tokens}} tokens, {{requests}} requêtes",
+      "sources": {
+        "user": "Chat",
+        "api": "API",
+        "cron": "Automatisations",
+        "dream": "Mémoire",
+        "system": "Système"
+      }
+    },
     "providers": {
       "searchPlaceholder": "Rechercher des fournisseurs",
       "noMatches": "Aucun fournisseur ne correspond.",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "Fermer l’objectif",
       "send": "Envoyer le message",
       "stop": "Arrêter la réponse",
+      "modelNotConfigured": "Modèle non configuré",
+      "configureModel": "Configurer le modèle",
       "queued": {
         "label": "Guidage en attente",
         "guide": "Guider",
@@ -733,6 +763,15 @@
     "next": "Image suivante",
     "close": "Fermer l’aperçu"
   },
+  "filePreview": {
+    "aria": "Aperçu du fichier",
+    "close": "Fermer l’aperçu du fichier",
+    "loading": "Chargement de l’aperçu...",
+    "failed": "Impossible de prévisualiser ce fichier.",
+    "routeMissing": "L’aperçu du fichier nécessite le dernier gateway. Redémarrez nanobot gateway puis réessayez.",
+    "resize": "Redimensionner l’aperçu du fichier",
+    "truncated": "L’aperçu est tronqué car le fichier est volumineux."
+  },
   "code": {
     "fallbackLanguage": "code",
     "copyAria": "Copier le code",
diff --git a/webui/src/i18n/locales/id/common.json b/webui/src/i18n/locales/id/common.json
index e17795046..d5b976dfb 100644
--- a/webui/src/i18n/locales/id/common.json
+++ b/webui/src/i18n/locales/id/common.json
@@ -187,6 +187,9 @@
       "disabled": "Nonaktif",
       "restartPending": "Menunggu mulai ulang",
       "ready": "Siap",
+      "privateEngine": "Mesin privat",
+      "unixSocket": "Soket Unix",
+      "defaultWorkspace": "Workspace default",
       "comfortable": "Nyaman",
       "compact": "Ringkas",
       "auto": "Otomatis",
@@ -278,6 +281,31 @@
       "imageGeneration": "Pembuatan gambar",
       "workspace": "Ruang kerja"
     },
+    "usage": {
+      "title": "Aktivitas token",
+      "shortTitle": "Token Usage",
+      "subtitle": "Penggunaan yang dilaporkan penyedia selama 12 bulan terakhir.",
+      "empty": "Aktivitas token akan muncul setelah balasan model baru.",
+      "totalTokens": "Total token",
+      "peakTokens": "Puncak token",
+      "thirtyDayTokens": "Token 30 hari",
+      "currentStreak": "Rentetan saat ini",
+      "longestStreak": "Rentetan terpanjang",
+      "daysValue": "{{count}} h",
+      "last30": "30 hari",
+      "activeDays": "Hari aktif",
+      "requests": "Permintaan",
+      "estimated": "perkiraan",
+      "includesEstimates": "termasuk perkiraan",
+      "cellTitle": "{{date}}: {{tokens}} token, {{requests}} permintaan",
+      "sources": {
+        "user": "Chat",
+        "api": "API",
+        "cron": "Otomasi",
+        "dream": "Memori",
+        "system": "Sistem"
+      }
+    },
     "providers": {
       "searchPlaceholder": "Cari penyedia",
       "noMatches": "Tidak ada penyedia yang cocok.",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "Tutup tujuan",
       "send": "Kirim pesan",
       "stop": "Hentikan respons",
+      "modelNotConfigured": "Model belum dikonfigurasi",
+      "configureModel": "Konfigurasi model",
       "queued": {
         "label": "Panduan antrean",
         "guide": "Pandu",
@@ -733,6 +763,15 @@
     "next": "Gambar berikutnya",
     "close": "Tutup pratinjau"
   },
+  "filePreview": {
+    "aria": "Pratinjau file",
+    "close": "Tutup pratinjau file",
+    "loading": "Memuat pratinjau...",
+    "failed": "Tidak dapat mempratinjau file ini.",
+    "routeMissing": "Pratinjau file memerlukan gateway terbaru. Mulai ulang nanobot gateway lalu coba lagi.",
+    "resize": "Ubah ukuran pratinjau file",
+    "truncated": "Pratinjau dipotong karena file ini besar."
+  },
   "code": {
     "fallbackLanguage": "kode",
     "copyAria": "Salin kode",
diff --git a/webui/src/i18n/locales/ja/common.json b/webui/src/i18n/locales/ja/common.json
index 9c07ece83..eee60f59b 100644
--- a/webui/src/i18n/locales/ja/common.json
+++ b/webui/src/i18n/locales/ja/common.json
@@ -187,6 +187,9 @@
       "disabled": "無効",
       "restartPending": "再起動待ち",
       "ready": "準備完了",
+      "privateEngine": "プライベートエンジン",
+      "unixSocket": "Unix ソケット",
+      "defaultWorkspace": "デフォルトワークスペース",
       "comfortable": "標準",
       "compact": "コンパクト",
       "auto": "自動",
@@ -278,6 +281,31 @@
       "imageGeneration": "画像生成",
       "workspace": "ワークスペース"
     },
+    "usage": {
+      "title": "Token アクティビティ",
+      "shortTitle": "Token Usage",
+      "subtitle": "直近 12 か月にプロバイダーが報告した使用量。",
+      "empty": "新しいモデル返信の後に token アクティビティが表示されます。",
+      "totalTokens": "累計 Token 数",
+      "peakTokens": "ピーク Token 数",
+      "thirtyDayTokens": "30 日 Token 数",
+      "currentStreak": "現在の連続日数",
+      "longestStreak": "最長連続日数",
+      "daysValue": "{{count}} 日",
+      "last30": "30 日",
+      "activeDays": "アクティブ日数",
+      "requests": "リクエスト",
+      "estimated": "推定",
+      "includesEstimates": "推定を含む",
+      "cellTitle": "{{date}}: {{tokens}} tokens, {{requests}} 件のリクエスト",
+      "sources": {
+        "user": "チャット",
+        "api": "API",
+        "cron": "自動タスク",
+        "dream": "メモリ整理",
+        "system": "システム"
+      }
+    },
     "providers": {
       "searchPlaceholder": "プロバイダーを検索",
       "noMatches": "一致するプロバイダーはありません。",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "目標を閉じる",
       "send": "メッセージを送信",
       "stop": "応答を停止",
+      "modelNotConfigured": "モデルが未設定です",
+      "configureModel": "モデルを設定",
       "queued": {
         "label": "保留中のガイド",
         "guide": "ガイド",
@@ -733,6 +763,15 @@
     "next": "次の画像",
     "close": "プレビューを閉じる"
   },
+  "filePreview": {
+    "aria": "ファイルプレビュー",
+    "close": "ファイルプレビューを閉じる",
+    "loading": "プレビューを読み込み中...",
+    "failed": "このファイルをプレビューできませんでした。",
+    "routeMissing": "ファイルプレビューには最新の gateway が必要です。nanobot gateway を再起動してから再試行してください。",
+    "resize": "ファイルプレビューの幅を変更",
+    "truncated": "ファイルが大きいため、プレビューは途中まで表示されています。"
+  },
   "code": {
     "fallbackLanguage": "コード",
     "copyAria": "コードをコピー",
diff --git a/webui/src/i18n/locales/ko/common.json b/webui/src/i18n/locales/ko/common.json
index cddf22634..db8ce076f 100644
--- a/webui/src/i18n/locales/ko/common.json
+++ b/webui/src/i18n/locales/ko/common.json
@@ -187,6 +187,9 @@
       "disabled": "비활성화됨",
       "restartPending": "재시작 대기",
       "ready": "준비됨",
+      "privateEngine": "비공개 엔진",
+      "unixSocket": "Unix 소켓",
+      "defaultWorkspace": "기본 작업 공간",
       "comfortable": "편안함",
       "compact": "컴팩트",
       "auto": "자동",
@@ -278,6 +281,31 @@
       "imageGeneration": "이미지 생성",
       "workspace": "작업공간"
     },
+    "usage": {
+      "title": "Token 활동",
+      "shortTitle": "Token Usage",
+      "subtitle": "최근 12개월 동안 제공자가 보고한 사용량입니다.",
+      "empty": "새 모델 응답 이후 token 활동이 표시됩니다.",
+      "totalTokens": "누적 Token 수",
+      "peakTokens": "최고 Token 수",
+      "thirtyDayTokens": "30일 Token 수",
+      "currentStreak": "현재 연속 일수",
+      "longestStreak": "최장 연속 일수",
+      "daysValue": "{{count}}일",
+      "last30": "30일",
+      "activeDays": "활성 일수",
+      "requests": "요청",
+      "estimated": "추정",
+      "includesEstimates": "추정 포함",
+      "cellTitle": "{{date}}: {{tokens}} tokens, 요청 {{requests}}회",
+      "sources": {
+        "user": "채팅",
+        "api": "API",
+        "cron": "자동화",
+        "dream": "메모리 정리",
+        "system": "시스템"
+      }
+    },
     "providers": {
       "searchPlaceholder": "제공자 검색",
       "noMatches": "일치하는 제공자가 없습니다.",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "목표 닫기",
       "send": "메시지 보내기",
       "stop": "응답 중지",
+      "modelNotConfigured": "모델이 설정되지 않음",
+      "configureModel": "모델 설정",
       "queued": {
         "label": "대기 중인 안내",
         "guide": "안내",
@@ -733,6 +763,15 @@
     "next": "다음 이미지",
     "close": "미리보기 닫기"
   },
+  "filePreview": {
+    "aria": "파일 미리보기",
+    "close": "파일 미리보기 닫기",
+    "loading": "미리보기 로딩 중...",
+    "failed": "이 파일을 미리 볼 수 없습니다.",
+    "routeMissing": "파일 미리보기에는 최신 gateway가 필요합니다. nanobot gateway를 다시 시작한 뒤 다시 시도하세요.",
+    "resize": "파일 미리보기 크기 조절",
+    "truncated": "파일이 커서 미리보기가 잘렸습니다."
+  },
   "code": {
     "fallbackLanguage": "코드",
     "copyAria": "코드 복사",
diff --git a/webui/src/i18n/locales/vi/common.json b/webui/src/i18n/locales/vi/common.json
index a8ef89e30..889482e04 100644
--- a/webui/src/i18n/locales/vi/common.json
+++ b/webui/src/i18n/locales/vi/common.json
@@ -187,6 +187,9 @@
       "disabled": "Đã tắt",
       "restartPending": "Chờ khởi động lại",
       "ready": "Sẵn sàng",
+      "privateEngine": "Bộ máy riêng",
+      "unixSocket": "Socket Unix",
+      "defaultWorkspace": "Workspace mặc định",
       "comfortable": "Thoải mái",
       "compact": "Gọn",
       "auto": "Tự động",
@@ -278,6 +281,31 @@
       "imageGeneration": "Tạo hình ảnh",
       "workspace": "Không gian làm việc"
     },
+    "usage": {
+      "title": "Hoạt động token",
+      "shortTitle": "Token Usage",
+      "subtitle": "Mức dùng do nhà cung cấp báo cáo trong 12 tháng gần nhất.",
+      "empty": "Hoạt động token sẽ xuất hiện sau các phản hồi mô hình mới.",
+      "totalTokens": "Tổng token",
+      "peakTokens": "Đỉnh token",
+      "thirtyDayTokens": "Token 30 ngày",
+      "currentStreak": "Chuỗi hiện tại",
+      "longestStreak": "Chuỗi dài nhất",
+      "daysValue": "{{count}} ngày",
+      "last30": "30 ngày",
+      "activeDays": "Ngày hoạt động",
+      "requests": "Yêu cầu",
+      "estimated": "ước tính",
+      "includesEstimates": "bao gồm ước tính",
+      "cellTitle": "{{date}}: {{tokens}} tokens, {{requests}} yêu cầu",
+      "sources": {
+        "user": "Trò chuyện",
+        "api": "API",
+        "cron": "Tự động hóa",
+        "dream": "Bộ nhớ",
+        "system": "Hệ thống"
+      }
+    },
     "providers": {
       "searchPlaceholder": "Tìm nhà cung cấp",
       "noMatches": "Không có nhà cung cấp phù hợp.",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "Đóng mục tiêu",
       "send": "Gửi tin nhắn",
       "stop": "Dừng phản hồi",
+      "modelNotConfigured": "Chưa cấu hình mô hình",
+      "configureModel": "Cấu hình mô hình",
       "queued": {
         "label": "Hướng dẫn đang chờ",
         "guide": "Hướng dẫn",
@@ -733,6 +763,15 @@
     "next": "Ảnh tiếp theo",
     "close": "Đóng xem trước"
   },
+  "filePreview": {
+    "aria": "Xem trước tệp",
+    "close": "Đóng xem trước tệp",
+    "loading": "Đang tải bản xem trước...",
+    "failed": "Không thể xem trước tệp này.",
+    "routeMissing": "Xem trước tệp cần gateway mới nhất. Hãy khởi động lại nanobot gateway rồi thử lại.",
+    "resize": "Đổi kích thước bản xem trước tệp",
+    "truncated": "Bản xem trước bị cắt vì tệp này lớn."
+  },
   "code": {
     "fallbackLanguage": "mã",
     "copyAria": "Sao chép mã",
diff --git a/webui/src/i18n/locales/zh-CN/common.json b/webui/src/i18n/locales/zh-CN/common.json
index b8efdd686..03b8b4ec1 100644
--- a/webui/src/i18n/locales/zh-CN/common.json
+++ b/webui/src/i18n/locales/zh-CN/common.json
@@ -295,6 +295,9 @@
       "disabled": "已禁用",
       "restartPending": "等待重启",
       "ready": "就绪",
+      "privateEngine": "私有引擎",
+      "unixSocket": "Unix socket",
+      "defaultWorkspace": "默认工作区",
       "comfortable": "舒适",
       "compact": "紧凑",
       "auto": "自动",
@@ -386,6 +389,31 @@
       "imageGeneration": "图片生成",
       "workspace": "工作区"
     },
+    "usage": {
+      "title": "Token 活动",
+      "shortTitle": "Token Usage",
+      "subtitle": "最近 12 个月由提供商上报的 token 用量。",
+      "empty": "新的模型回复产生后，这里会显示 token 活动。",
+      "totalTokens": "累计 Token 数",
+      "peakTokens": "峰值 Token 数",
+      "thirtyDayTokens": "30 天 Token 数",
+      "currentStreak": "当前连续天数",
+      "longestStreak": "最长连续天数",
+      "daysValue": "{{count}} 天",
+      "last30": "30 天",
+      "activeDays": "活跃天数",
+      "requests": "请求数",
+      "estimated": "估算",
+      "includesEstimates": "包含估算",
+      "cellTitle": "{{date}}：{{tokens}} tokens，{{requests}} 次请求",
+      "sources": {
+        "user": "对话",
+        "api": "API",
+        "cron": "自动任务",
+        "dream": "记忆整理",
+        "system": "系统"
+      }
+    },
     "providers": {
       "searchPlaceholder": "搜索提供商",
       "noMatches": "没有匹配的提供商。",
@@ -564,6 +592,8 @@
       "goalStateSheetTitle": "目标",
       "send": "发送消息",
       "stop": "停止响应",
+      "modelNotConfigured": "模型未配置",
+      "configureModel": "配置模型",
       "queued": {
         "label": "待引导提示",
         "guide": "引导",
@@ -733,6 +763,15 @@
     "next": "下一张",
     "close": "关闭预览"
   },
+  "filePreview": {
+    "aria": "文件预览",
+    "close": "关闭文件预览",
+    "loading": "正在加载预览...",
+    "failed": "无法预览这个文件。",
+    "routeMissing": "文件预览需要最新的 gateway。请重启 nanobot gateway 后再试。",
+    "resize": "调整文件预览宽度",
+    "truncated": "文件较大，当前只显示前半部分预览。"
+  },
   "code": {
     "fallbackLanguage": "代码",
     "copyAria": "复制代码",
diff --git a/webui/src/i18n/locales/zh-TW/common.json b/webui/src/i18n/locales/zh-TW/common.json
index 810a938e1..4ea3ce95f 100644
--- a/webui/src/i18n/locales/zh-TW/common.json
+++ b/webui/src/i18n/locales/zh-TW/common.json
@@ -187,6 +187,9 @@
       "disabled": "已停用",
       "restartPending": "等待重啟",
       "ready": "就緒",
+      "privateEngine": "私有引擎",
+      "unixSocket": "Unix socket",
+      "defaultWorkspace": "預設工作區",
       "comfortable": "舒適",
       "compact": "緊湊",
       "auto": "自動",
@@ -278,6 +281,31 @@
       "imageGeneration": "圖片生成",
       "workspace": "工作區"
     },
+    "usage": {
+      "title": "Token 活動",
+      "shortTitle": "Token Usage",
+      "subtitle": "最近 12 個月由供應商回報的 token 用量。",
+      "empty": "新的模型回覆產生後，這裡會顯示 token 活動。",
+      "totalTokens": "累計 Token 數",
+      "peakTokens": "峰值 Token 數",
+      "thirtyDayTokens": "30 天 Token 數",
+      "currentStreak": "目前連續天數",
+      "longestStreak": "最長連續天數",
+      "daysValue": "{{count}} 天",
+      "last30": "30 天",
+      "activeDays": "活躍天數",
+      "requests": "請求數",
+      "estimated": "估算",
+      "includesEstimates": "包含估算",
+      "cellTitle": "{{date}}：{{tokens}} tokens，{{requests}} 次請求",
+      "sources": {
+        "user": "對話",
+        "api": "API",
+        "cron": "自動任務",
+        "dream": "記憶整理",
+        "system": "系統"
+      }
+    },
     "providers": {
       "searchPlaceholder": "搜尋供應商",
       "noMatches": "沒有符合的供應商。",
@@ -565,6 +593,8 @@
       "goalStateCloseAria": "關閉目標",
       "send": "送出訊息",
       "stop": "停止回覆",
+      "modelNotConfigured": "模型未配置",
+      "configureModel": "配置模型",
       "queued": {
         "label": "待引導提示",
         "guide": "引導",
@@ -733,6 +763,15 @@
     "next": "下一張",
     "close": "關閉預覽"
   },
+  "filePreview": {
+    "aria": "檔案預覽",
+    "close": "關閉檔案預覽",
+    "loading": "正在載入預覽...",
+    "failed": "無法預覽這個檔案。",
+    "routeMissing": "檔案預覽需要最新的 gateway。請重啟 nanobot gateway 後再試。",
+    "resize": "調整檔案預覽寬度",
+    "truncated": "檔案較大，目前只顯示前半部分預覽。"
+  },
   "code": {
     "fallbackLanguage": "程式碼",
     "copyAria": "複製程式碼",
diff --git a/webui/src/lib/activity-timeline.ts b/webui/src/lib/activity-timeline.ts
index 831c8e262..9f2b049b6 100644
--- a/webui/src/lib/activity-timeline.ts
+++ b/webui/src/lib/activity-timeline.ts
@@ -38,6 +38,10 @@ export type TurnUnit =
   | { type: "activity"; messages: UIMessage[]; items: ActivityItem[]; turnLatencyMs?: number }
   | { type: "message"; message: UIMessage };
 
+interface NormalizeActivityTimelineOptions {
+  preserveTrailingActivity?: boolean;
+}
+
 export function isReasoningOnlyAssistant(message: UIMessage): boolean {
   if (message.role !== "assistant" || message.kind === "trace") return false;
   if (message.content.trim().length > 0) return false;
@@ -48,24 +52,30 @@ export function isAgentActivityMember(message: UIMessage): boolean {
   return isReasoningOnlyAssistant(message) || message.kind === "trace";
 }
 
-export function normalizeActivityTimeline(messages: UIMessage[]): TurnUnit[] {
+export function normalizeActivityTimeline(
+  messages: UIMessage[],
+  options: NormalizeActivityTimelineOptions = {},
+): TurnUnit[] {
   const units: TurnUnit[] = [];
   let turnMessages: UIMessage[] = [];
+  let activeTurnId: string | undefined;
 
-  const flushTurn = () => {
+  const flushTurn = (flushOptions: NormalizeActivityTimelineOptions = {}) => {
     if (turnMessages.length === 0) return;
 
-    const visibleMessages = visibleMessagesForTurn(turnMessages);
+    const turnUnits: TurnUnit[] = [];
+    const orderedTurnMessages = orderMessagesByTurnSeq(turnMessages);
+    const visibleMessages = visibleMessagesForTurn(orderedTurnMessages);
     let visibleIndex = 0;
     let activityMessages: UIMessage[] = [];
 
     const flushActivityMessages = () => {
       if (!activityMessages.length) return;
-      pushActivityUnits(units, activityMessages, visibleMessages.slice(visibleIndex));
+      pushActivityUnits(turnUnits, activityMessages, visibleMessages.slice(visibleIndex));
       activityMessages = [];
     };
 
-    for (const message of turnMessages) {
+    for (const message of orderedTurnMessages) {
       if (isAgentActivityMember(message)) {
         activityMessages.push(message);
         continue;
@@ -74,34 +84,87 @@ export function normalizeActivityTimeline(messages: UIMessage[]): TurnUnit[] {
       if (assistantHasInlineReasoning(message)) {
         activityMessages.push(reasoningOnlyMessageFromAnswer(message));
         flushActivityMessages();
-        units.push({ type: "message", message: stripInlineReasoning(message) });
+        turnUnits.push({ type: "message", message: stripInlineReasoning(message) });
         visibleIndex += 1;
         continue;
       }
 
       flushActivityMessages();
-      units.push({ type: "message", message });
+      turnUnits.push({ type: "message", message });
       visibleIndex += 1;
     }
 
     flushActivityMessages();
+    units.push(...normalizeCompletedTurnUnits(turnUnits, flushOptions));
     turnMessages = [];
+    activeTurnId = undefined;
   };
 
   for (const message of messages) {
     if (message.role === "user") {
       flushTurn();
       units.push({ type: "message", message });
+      activeTurnId = message.turnId;
       continue;
     }
 
+    if (message.turnId && activeTurnId && message.turnId !== activeTurnId) {
+      flushTurn();
+    }
+    if (message.turnId) {
+      activeTurnId = message.turnId;
+    }
     turnMessages.push(message);
   }
 
-  flushTurn();
+  flushTurn(options);
   return units;
 }
 
+function orderMessagesByTurnSeq(messages: UIMessage[]): UIMessage[] {
+  if (
+    messages.length < 2
+    || !messages.every((message) => Number.isFinite(message.turnSeq))
+  ) {
+    return messages;
+  }
+  return messages
+    .map((message, index) => ({ message, index }))
+    .sort((left, right) => {
+      const bySeq = (left.message.turnSeq ?? 0) - (right.message.turnSeq ?? 0);
+      return bySeq || left.index - right.index;
+    })
+    .map(({ message }) => message);
+}
+
+function normalizeCompletedTurnUnits(
+  turnUnits: TurnUnit[],
+  options: NormalizeActivityTimelineOptions,
+): TurnUnit[] {
+  if (options.preserveTrailingActivity || turnUnits.length < 2) return turnUnits;
+  if (turnUnits[turnUnits.length - 1]?.type !== "activity") return turnUnits;
+
+  let trailingStart = turnUnits.length - 1;
+  while (trailingStart > 0 && turnUnits[trailingStart - 1]?.type === "activity") {
+    trailingStart -= 1;
+  }
+
+  const previous = turnUnits[trailingStart - 1];
+  if (
+    !previous
+    || previous.type !== "message"
+    || previous.message.role !== "assistant"
+  ) {
+    return turnUnits;
+  }
+
+  return [
+    ...turnUnits.slice(0, trailingStart - 1),
+    ...turnUnits.slice(trailingStart),
+    previous,
+  ];
+}
+
 function visibleMessagesForTurn(messages: UIMessage[]): UIMessage[] {
   const visibleMessages: UIMessage[] = [];
   for (const message of messages) {
diff --git a/webui/src/lib/api.ts b/webui/src/lib/api.ts
index 156e49e35..f1355be98 100644
--- a/webui/src/lib/api.ts
+++ b/webui/src/lib/api.ts
@@ -1,6 +1,7 @@
 import type {
   ChatSummary,
   CliAppsPayload,
+  FilePreviewPayload,
   ImageGenerationSettingsUpdate,
   McpPresetsPayload,
   ModelConfigurationCreate,
@@ -134,6 +135,22 @@ export async function fetchWebuiThread(
   return (await res.json()) as WebuiThreadPersistedPayload;
 }
 
+export async function fetchFilePreview(
+  token: string,
+  key: string,
+  path: string,
+  base: string = "",
+): Promise<FilePreviewPayload> {
+  const query = new URLSearchParams();
+  query.set("path", path);
+  return request<FilePreviewPayload>(
+    `${base}/api/sessions/${encodeURIComponent(key)}/file-preview?${query}`,
+    token,
+    undefined,
+    API_READ_TIMEOUT_MS,
+  );
+}
+
 export async function deleteSession(
   token: string,
   key: string,
@@ -158,6 +175,18 @@ export async function fetchSettings(
   );
 }
 
+export async function fetchSettingsUsage(
+  token: string,
+  base: string = "",
+): Promise<NonNullable<SettingsPayload["usage"]>> {
+  return request<NonNullable<SettingsPayload["usage"]>>(
+    `${base}/api/settings/usage`,
+    token,
+    undefined,
+    API_READ_TIMEOUT_MS,
+  );
+}
+
 export async function fetchWorkspaces(
   token: string,
   base: string = "",
diff --git a/webui/src/lib/nanobot-client.ts b/webui/src/lib/nanobot-client.ts
index a739afb2e..8e43cf8ae 100644
--- a/webui/src/lib/nanobot-client.ts
+++ b/webui/src/lib/nanobot-client.ts
@@ -336,6 +336,7 @@ export class NanobotClient {
       cliApps?: OutboundCliAppMention[];
       mcpPresets?: OutboundMcpPresetMention[];
       workspaceScope?: WorkspaceScopePayload | null;
+      turnId?: string;
     },
   ): void {
     this.knownChats.add(chatId);
@@ -348,6 +349,7 @@ export class NanobotClient {
       ...(options?.cliApps?.length ? { cli_apps: options.cliApps } : {}),
       ...(options?.mcpPresets?.length ? { mcp_presets: options.mcpPresets } : {}),
       ...(options?.workspaceScope ? { workspace_scope: options.workspaceScope } : {}),
+      ...(options?.turnId ? { turn_id: options.turnId } : {}),
       webui: true,
     };
     this.queueSend(frame);
diff --git a/webui/src/lib/types.ts b/webui/src/lib/types.ts
index b6924cf96..34cba38a8 100644
--- a/webui/src/lib/types.ts
+++ b/webui/src/lib/types.ts
@@ -4,6 +4,8 @@ export type Role = "user" | "assistant" | "tool" | "system";
  * progress pings) that should not be rendered as conversational replies. */
 export type MessageKind = "message" | "trace";
 
+export type UITurnPhase = "user" | "reasoning" | "activity" | "answer" | "complete";
+
 /** One image attached to a UIMessage.
  *
  * ``url`` can arrive in three different shapes, which the bubble renders
@@ -64,6 +66,10 @@ export interface UIMessage {
   reasoningStreaming?: boolean;
   /** End-to-end wall time for this assistant turn (persisted ``latency_ms`` / ``turn_end``). */
   latencyMs?: number;
+  /** Stable protocol metadata for grouping all activity emitted by one user turn. */
+  turnId?: string;
+  turnPhase?: UITurnPhase;
+  turnSeq?: number;
 }
 
 export interface UICliAppAttachment {
@@ -352,6 +358,43 @@ export interface SettingsPayload {
     };
     unified_session: boolean;
   };
+  usage?: {
+    days: Array<{
+      date: string;
+      prompt_tokens: number;
+      completion_tokens: number;
+      cached_tokens: number;
+      total_tokens: number;
+      provider_tokens?: number;
+      estimated_tokens?: number;
+      requests: number;
+      provider_requests?: number;
+      estimated_requests?: number;
+      sources?: Record<
+        "user" | "api" | "cron" | "dream" | "system" | string,
+        {
+          prompt_tokens: number;
+          completion_tokens: number;
+          cached_tokens: number;
+          total_tokens: number;
+          provider_tokens?: number;
+          estimated_tokens?: number;
+          requests: number;
+          provider_requests?: number;
+          estimated_requests?: number;
+        }
+      >;
+    }>;
+    total_tokens: number;
+    total_tokens_30d: number;
+    total_tokens_365d: number;
+    peak_day_tokens: number;
+    current_streak_days: number;
+    longest_streak_days: number;
+    active_days_30d: number;
+    requests_30d: number;
+    updated_at?: string | null;
+  };
   advanced: {
     restrict_to_workspace: boolean;
     workspace_sandbox?: {
@@ -605,10 +648,16 @@ export type ConnectionStatus =
   | "closed"
   | "error";
 
+export interface InboundTurnMetadata {
+  turn_id?: string;
+  turn_phase?: UITurnPhase;
+  turn_seq?: number;
+}
+
 export type InboundEvent =
   | { event: "ready"; chat_id: string; client_id: string }
   | { event: "attached"; chat_id: string }
-  | {
+  | ({
       event: "message";
       chat_id: string;
       text: string;
@@ -623,47 +672,47 @@ export type InboundEvent =
       latency_ms?: number;
       /** Optional structured payload on progress frames (channel-specific). */
       agent_ui?: AgentUIBlob;
-    }
-  | {
+    } & InboundTurnMetadata)
+  | ({
       event: "file_edit";
       chat_id: string;
       edits: UIFileEdit[];
-    }
-  | {
+    } & InboundTurnMetadata)
+  | ({
       event: "delta";
       chat_id: string;
       text: string;
       stream_id?: string;
-    }
-  | {
+    } & InboundTurnMetadata)
+  | ({
       event: "stream_end";
       chat_id: string;
       stream_id?: string;
       text?: string;
-    }
-  | {
+    } & InboundTurnMetadata)
+  | ({
       event: "reasoning_delta";
       chat_id: string;
       text: string;
       stream_id?: string;
-    }
-  | {
+    } & InboundTurnMetadata)
+  | ({
       event: "reasoning_end";
       chat_id: string;
       stream_id?: string;
-    }
+    } & InboundTurnMetadata)
   | {
       event: "runtime_model_updated";
       model_name: string;
       model_preset?: string | null;
     }
-  | {
+  | ({
       event: "turn_end";
       chat_id: string;
       latency_ms?: number;
       /** Authoritative sustained-goal snapshot for this chat (same shape as ``goal_state`` events). */
       goal_state?: GoalStateWsPayload;
-    }
+    } & InboundTurnMetadata)
   | {
       event: "goal_status";
       chat_id: string;
@@ -732,6 +781,16 @@ export interface WebuiThreadPersistedPayload {
   workspace_scope?: WorkspaceScopePayload;
 }
 
+export interface FilePreviewPayload {
+  path: string;
+  display_path: string;
+  project_path: string;
+  language: string;
+  content: string;
+  size: number;
+  truncated: boolean;
+}
+
 export type Outbound =
   | { type: "new_chat"; workspace_scope?: WorkspaceScopePayload }
   | { type: "attach"; chat_id: string }
@@ -745,6 +804,7 @@ export type Outbound =
       cli_apps?: OutboundCliAppMention[];
       mcp_presets?: OutboundMcpPresetMention[];
       workspace_scope?: WorkspaceScopePayload;
+      turn_id?: string;
       /** Marks messages sent by the embedded WebUI, without changing the
        * generic websocket protocol for other clients. */
       webui?: true;
diff --git a/webui/src/tests/api.test.ts b/webui/src/tests/api.test.ts
index 6e4b8ab28..c8630c11f 100644
--- a/webui/src/tests/api.test.ts
+++ b/webui/src/tests/api.test.ts
@@ -3,9 +3,11 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import {
   createModelConfiguration,
   deleteSession,
+  fetchFilePreview,
   fetchCliApps,
   fetchMcpPresets,
   fetchProviderModels,
+  fetchSettingsUsage,
   fetchSidebarState,
   fetchWebuiThread,
   fetchWorkspaces,
@@ -55,6 +57,18 @@ describe("webui API helpers", () => {
     );
   });
 
+  it("percent-encodes websocket keys and paths when fetching file previews", async () => {
+    await fetchFilePreview("tok", "websocket:chat-1", "/tmp/project/hook.py:12");
+
+    expect(fetch).toHaveBeenCalledWith(
+      "/api/sessions/websocket%3Achat-1/file-preview?path=%2Ftmp%2Fproject%2Fhook.py%3A12",
+      expect.objectContaining({
+        headers: { Authorization: "Bearer tok" },
+        credentials: "same-origin",
+      }),
+    );
+  });
+
   it("percent-encodes websocket keys when deleting a session", async () => {
     await deleteSession("tok", "websocket:chat-1");
 
@@ -86,6 +100,17 @@ describe("webui API helpers", () => {
     );
   });
 
+  it("fetches token usage through the lightweight settings endpoint", async () => {
+    await fetchSettingsUsage("tok");
+
+    expect(fetch).toHaveBeenCalledWith(
+      "/api/settings/usage",
+      expect.objectContaining({
+        headers: { Authorization: "Bearer tok" },
+      }),
+    );
+  });
+
   it("serializes model configuration creation", async () => {
     await createModelConfiguration("tok", {
       label: "Fast writing",
diff --git a/webui/src/tests/app-layout.test.tsx b/webui/src/tests/app-layout.test.tsx
index 870f71e16..a7b8260d6 100644
--- a/webui/src/tests/app-layout.test.tsx
+++ b/webui/src/tests/app-layout.test.tsx
@@ -208,6 +208,7 @@ describe("App layout", () => {
     runStatusHandlers.clear();
     window.history.replaceState(null, "", "/");
     setNavigatorPlatform("Linux x86_64");
+    localStorage.removeItem("nanobot-webui.sidebar");
     localStorage.removeItem("nanobot-webui.sidebar.completed-runs.v1");
     vi.mocked(fetchBootstrap).mockReset().mockResolvedValue({
       token: "tok",
@@ -243,6 +244,60 @@ describe("App layout", () => {
     expect(asideClassNames.some((cls) => cls.includes("lg:block"))).toBe(true);
   });
 
+  it("fully collapses the native host sidebar and previews it on hover", async () => {
+    mockSessions = [
+      {
+        key: "websocket:chat-a",
+        channel: "websocket",
+        chatId: "chat-a",
+        createdAt: "2026-04-16T10:00:00Z",
+        updatedAt: "2026-04-16T10:00:00Z",
+        preview: "Desktop chat",
+      },
+    ];
+    vi.mocked(fetchBootstrap).mockResolvedValue({
+      token: "tok",
+      ws_path: "/",
+      expires_in: 300,
+      runtime_surface: "native",
+    });
+
+    render(<App />);
+
+    await waitFor(() => expect(connectSpy).toHaveBeenCalled());
+    const flowSidebar = screen.getByTestId("host-sidebar-flow");
+    const toggle = screen.getByTestId("host-sidebar-toggle");
+    expect(flowSidebar).toHaveStyle({ width: "272px" });
+    expect(
+      screen.getByRole("navigation", { name: "Sidebar navigation" }),
+    ).toBeInTheDocument();
+
+    fireEvent.click(toggle);
+    await waitFor(() => expect(flowSidebar).toHaveStyle({ width: "0px" }));
+    expect(
+      screen.queryByRole("navigation", { name: "Sidebar navigation" }),
+    ).not.toBeInTheDocument();
+
+    fireEvent.mouseEnter(toggle);
+    const previewSidebar = await screen.findByTestId("host-sidebar-preview");
+    expect(flowSidebar).toHaveStyle({ width: "0px" });
+    expect(previewSidebar).toHaveStyle({ width: "272px" });
+    expect(
+      within(previewSidebar).getByRole("navigation", {
+        name: "Sidebar navigation",
+      }),
+    ).toBeInTheDocument();
+
+    fireEvent.click(toggle);
+    await waitFor(() =>
+      expect(screen.queryByTestId("host-sidebar-preview")).not.toBeInTheDocument(),
+    );
+    expect(flowSidebar).toHaveStyle({ width: "272px" });
+    expect(
+      screen.getByRole("navigation", { name: "Sidebar navigation" }),
+    ).toBeInTheDocument();
+  });
+
   it("switches to the next session when deleting the active chat", async () => {
     mockSessions = [
       {
@@ -907,7 +962,6 @@ describe("App layout", () => {
 
     expect(await screen.findByRole("heading", { name: "Overview" })).toBeInTheDocument();
     expect(document.title).toBe("Settings · nanobot");
-    expect(screen.getByTestId("overview-nanobot-logo")).toBeInTheDocument();
     expect(screen.getByTestId("overview-logo-openai")).toBeInTheDocument();
     expect(screen.getByTestId("overview-logo-brave")).toBeInTheDocument();
     expect(screen.getByTestId("overview-logo-openrouter")).toBeInTheDocument();
diff --git a/webui/src/tests/code-block.test.tsx b/webui/src/tests/code-block.test.tsx
index 94f2c4832..c52ef2743 100644
--- a/webui/src/tests/code-block.test.tsx
+++ b/webui/src/tests/code-block.test.tsx
@@ -51,6 +51,25 @@ describe("CodeBlock", () => {
     expect(screen.getByTestId("plain-code-fallback")).toHaveClass("text-foreground/90");
   });
 
+  it("can render without chat-style chrome for file previews", () => {
+    render(
+      <ThemeProvider theme="light">
+        <CodeBlock
+          language="html"
+          code="<main />"
+          chrome="none"
+          highlight={false}
+          showLineNumbers
+        />
+      </ThemeProvider>,
+    );
+
+    expect(screen.queryByText("html")).not.toBeInTheDocument();
+    expect(screen.queryByRole("button", { name: /copy/i })).not.toBeInTheDocument();
+    expect(screen.getByText("1")).toBeInTheDocument();
+    expect(screen.getByTestId("plain-code-fallback")).toHaveClass("bg-transparent");
+  });
+
   it("falls back to 'text' language when language is undefined", async () => {
     render(
       <ThemeProvider theme="dark">
diff --git a/webui/src/tests/markdown-text-renderer.test.tsx b/webui/src/tests/markdown-text-renderer.test.tsx
index 596dde98b..3af72566e 100644
--- a/webui/src/tests/markdown-text-renderer.test.tsx
+++ b/webui/src/tests/markdown-text-renderer.test.tsx
@@ -1,5 +1,5 @@
-import { render, screen } from "@testing-library/react";
-import { describe, expect, it } from "vitest";
+import { fireEvent, render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
 
 import MarkdownTextRenderer from "@/components/MarkdownTextRenderer";
 
@@ -12,6 +12,43 @@ describe("MarkdownTextRenderer", () => {
     expect(link).toHaveClass("text-blue-500", "dark:text-blue-300");
   });
 
+  it("renders local file links as previewable file references", () => {
+    const onOpenFilePreview = vi.fn();
+    render(
+      <MarkdownTextRenderer onOpenFilePreview={onOpenFilePreview}>
+        {"Edited [hook.py](/Users/test/project/nanobot/agent/hook.py:12)"}
+      </MarkdownTextRenderer>,
+    );
+
+    const reference = screen.getByTestId("inline-file-path");
+    expect(reference).toHaveTextContent("hook.py");
+    expect(reference).toHaveAttribute(
+      "aria-label",
+      "/Users/test/project/nanobot/agent/hook.py",
+    );
+
+    fireEvent.click(reference);
+
+    expect(onOpenFilePreview).toHaveBeenCalledWith(
+      "/Users/test/project/nanobot/agent/hook.py",
+    );
+  });
+
+  it("does not treat non-file hrefs as previews just because the label looks like a file", () => {
+    const onOpenFilePreview = vi.fn();
+    render(
+      <MarkdownTextRenderer onOpenFilePreview={onOpenFilePreview}>
+        {"Download [index.html](/api/media/sig/html)"}
+      </MarkdownTextRenderer>,
+    );
+
+    expect(screen.queryByTestId("inline-file-path")).not.toBeInTheDocument();
+    expect(screen.getByRole("link", { name: "index.html" })).toHaveAttribute(
+      "href",
+      "/api/media/sig/html",
+    );
+  });
+
   it("does not wrap complete fenced code blocks in an extra pre", () => {
     const { container } = render(
       <MarkdownTextRenderer highlightCode={false}>
diff --git a/webui/src/tests/nanobot-client.test.ts b/webui/src/tests/nanobot-client.test.ts
index fdfad82c7..52b1ea69c 100644
--- a/webui/src/tests/nanobot-client.test.ts
+++ b/webui/src/tests/nanobot-client.test.ts
@@ -429,6 +429,24 @@ describe("NanobotClient", () => {
     );
   });
 
+  it("includes an explicit turn id on outbound WebUI messages", () => {
+    const client = new NanobotClient({
+      url: "ws://test",
+      reconnect: false,
+      socketFactory: (url) => new FakeSocket(url) as unknown as WebSocket,
+    });
+    client.connect();
+    lastSocket().fakeOpen();
+    client.sendMessage("chat-x", "hello", undefined, { turnId: "turn-1" });
+    expect(JSON.parse(lastSocket().sent.at(-1) as string)).toEqual({
+      type: "message",
+      chat_id: "chat-x",
+      content: "hello",
+      turn_id: "turn-1",
+      webui: true,
+    });
+  });
+
   it("includes image generation options in outbound messages", () => {
     const client = new NanobotClient({
       url: "ws://test",
diff --git a/webui/src/tests/settings-view.test.tsx b/webui/src/tests/settings-view.test.tsx
index 0cfe70e0c..2204f210c 100644
--- a/webui/src/tests/settings-view.test.tsx
+++ b/webui/src/tests/settings-view.test.tsx
@@ -118,7 +118,7 @@ const installedAnyGen = {
 
 function renderSettingsView(
   options: {
-    initialSection?: "apps" | "advanced" | "models";
+    initialSection?: "overview" | "apps" | "advanced" | "models";
     onSettingsChange?: (payload: SettingsPayload) => void;
   } = {},
 ) {
@@ -219,6 +219,55 @@ describe("SettingsView Apps catalog", () => {
     await waitFor(() => expect(onSettingsChange).toHaveBeenCalledWith(payload));
   });
 
+  it("shows token activity on the overview", async () => {
+    const payload: SettingsPayload = {
+      ...settingsPayload(),
+      usage: {
+        days: [
+          {
+            date: "2026-06-03",
+            prompt_tokens: 1200,
+            completion_tokens: 300,
+            cached_tokens: 500,
+            total_tokens: 1500,
+            requests: 2,
+          },
+        ],
+        total_tokens: 1500,
+        total_tokens_30d: 1500,
+        total_tokens_365d: 1500,
+        peak_day_tokens: 1500,
+        current_streak_days: 1,
+        longest_streak_days: 1,
+        active_days_30d: 1,
+        requests_30d: 2,
+        updated_at: "2026-06-03T00:00:00Z",
+      },
+    };
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async (input: RequestInfo | URL) => {
+        const url = String(input);
+        if (url === "/api/settings") return jsonResponse(payload);
+        if (url === "/api/settings/cli-apps") {
+          return jsonResponse({ apps: [], installed_count: 0 });
+        }
+        if (url === "/api/settings/mcp-presets") {
+          return jsonResponse({ presets: [], installed_count: 0 });
+        }
+        return { ok: false, status: 404, json: async () => ({}) } as Response;
+      }),
+    );
+
+    renderSettingsView({ initialSection: "overview" });
+
+    expect(await screen.findByLabelText("Token activity")).toBeInTheDocument();
+    expect(screen.getByText("Token Usage")).toBeInTheDocument();
+    expect(screen.queryByText("Token activity")).not.toBeInTheDocument();
+    expect(screen.queryByText("Total tokens")).not.toBeInTheDocument();
+    expect(screen.queryByText("Peak tokens")).not.toBeInTheDocument();
+  });
+
   it("shows context window options in model settings", async () => {
     vi.stubGlobal(
       "fetch",
@@ -242,6 +291,280 @@ describe("SettingsView Apps catalog", () => {
     expect(screen.getByRole("button", { name: "256K" })).toBeInTheDocument();
   });
 
+  it("marks the current model as unconfigured when its provider needs setup", async () => {
+    const payload: SettingsPayload = {
+      ...settingsPayload(),
+      agent: {
+        ...settingsPayload().agent,
+        model: "openai-codex/gpt-5.1-codex",
+        provider: "openai_codex",
+        resolved_provider: "openai_codex",
+        has_api_key: false,
+      },
+      model_presets: [
+        {
+          ...settingsPayload().model_presets[0],
+          model: "openai-codex/gpt-5.1-codex",
+          provider: "openai_codex",
+        },
+      ],
+      providers: [
+        {
+          name: "openai_codex",
+          label: "OpenAI Codex",
+          configured: false,
+          auth_type: "oauth",
+          api_key_required: false,
+          api_key_hint: null,
+          api_base: null,
+          default_api_base: null,
+          oauth_account: null,
+          oauth_expires_at: null,
+          oauth_login_supported: true,
+        },
+      ],
+    };
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async (input: RequestInfo | URL) => {
+        const url = String(input);
+        if (url === "/api/settings") return jsonResponse(payload);
+        if (url === "/api/settings/cli-apps") {
+          return jsonResponse({ apps: [], installed_count: 0 });
+        }
+        if (url === "/api/settings/mcp-presets") {
+          return jsonResponse({ presets: [], installed_count: 0 });
+        }
+        return { ok: false, status: 404, json: async () => ({}) } as Response;
+      }),
+    );
+
+    renderSettingsView({ initialSection: "models" });
+
+    const configurationButton = await screen.findByRole("button", {
+      name: "Current configuration",
+    });
+    expect(configurationButton).toHaveTextContent("Not configured");
+    expect(configurationButton).toHaveTextContent("OpenAI Codex · openai-codex/gpt-5.1-codex");
+    expect(await screen.findByRole("button", { name: "Sign in" })).toBeInTheDocument();
+  });
+
+  it("keeps unsigned OAuth providers out of the active provider picker", async () => {
+    const payload: SettingsPayload = {
+      ...settingsPayload(),
+      agent: {
+        ...settingsPayload().agent,
+        model: "deepseek-chat",
+        provider: "deepseek",
+        resolved_provider: "deepseek",
+      },
+      model_presets: [
+        {
+          ...settingsPayload().model_presets[0],
+          model: "deepseek-chat",
+          provider: "deepseek",
+        },
+      ],
+      providers: [
+        {
+          name: "deepseek",
+          label: "DeepSeek",
+          configured: true,
+          auth_type: "api_key",
+          api_key_required: true,
+          api_key_hint: "sk-...",
+          api_base: "https://api.deepseek.com",
+          default_api_base: "https://api.deepseek.com",
+        },
+        {
+          name: "openai_codex",
+          label: "OpenAI Codex",
+          configured: false,
+          auth_type: "oauth",
+          api_key_required: false,
+          api_key_hint: null,
+          api_base: null,
+          default_api_base: null,
+          oauth_account: null,
+          oauth_expires_at: null,
+          oauth_login_supported: true,
+        },
+        {
+          name: "github_copilot",
+          label: "GitHub Copilot",
+          configured: false,
+          auth_type: "oauth",
+          api_key_required: false,
+          api_key_hint: null,
+          api_base: null,
+          default_api_base: "https://api.githubcopilot.com",
+          oauth_account: null,
+          oauth_expires_at: null,
+          oauth_login_supported: true,
+        },
+      ],
+    };
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async (input: RequestInfo | URL) => {
+        const url = String(input);
+        if (url === "/api/settings") return jsonResponse(payload);
+        if (url === "/api/settings/cli-apps") {
+          return jsonResponse({ apps: [], installed_count: 0 });
+        }
+        if (url === "/api/settings/mcp-presets") {
+          return jsonResponse({ presets: [], installed_count: 0 });
+        }
+        return { ok: false, status: 404, json: async () => ({}) } as Response;
+      }),
+    );
+
+    renderSettingsView({ initialSection: "models" });
+
+    const deepseekButtons = await screen.findAllByRole("button", { name: /DeepSeek/ });
+    const providerPicker = deepseekButtons.find(
+      (button) => button.getAttribute("aria-haspopup") === "menu",
+    );
+    if (!providerPicker) throw new Error("provider picker was not found");
+    fireEvent.pointerDown(providerPicker);
+
+    expect(await screen.findByRole("menuitem", { name: /DeepSeek/ })).toBeInTheDocument();
+    expect(screen.queryByRole("menuitem", { name: /OpenAI Codex/ })).not.toBeInTheDocument();
+    expect(screen.queryByRole("menuitem", { name: /GitHub Copilot/ })).not.toBeInTheDocument();
+  });
+
+  it("does not fetch model lists for unsigned OAuth providers", async () => {
+    const payload: SettingsPayload = {
+      ...settingsPayload(),
+      agent: {
+        ...settingsPayload().agent,
+        model: "",
+        provider: "openai_codex",
+        resolved_provider: "openai_codex",
+      },
+      model_presets: [
+        {
+          ...settingsPayload().model_presets[0],
+          model: "",
+          provider: "openai_codex",
+        },
+      ],
+      providers: [
+        {
+          name: "openai_codex",
+          label: "OpenAI Codex",
+          configured: false,
+          auth_type: "oauth",
+          api_key_required: false,
+          api_key_hint: null,
+          api_base: null,
+          default_api_base: null,
+          oauth_account: null,
+          oauth_expires_at: null,
+          oauth_login_supported: true,
+        },
+        {
+          name: "github_copilot",
+          label: "GitHub Copilot",
+          configured: false,
+          auth_type: "oauth",
+          api_key_required: false,
+          api_key_hint: null,
+          api_base: null,
+          default_api_base: "https://api.githubcopilot.com",
+          oauth_account: null,
+          oauth_expires_at: null,
+          oauth_login_supported: true,
+        },
+      ],
+    };
+    const fetchMock = vi.fn(async (input: RequestInfo | URL) => {
+      const url = String(input);
+      if (url === "/api/settings") return jsonResponse(payload);
+      if (url === "/api/settings/cli-apps") {
+        return jsonResponse({ apps: [], installed_count: 0 });
+      }
+      if (url === "/api/settings/mcp-presets") {
+        return jsonResponse({ presets: [], installed_count: 0 });
+      }
+      return { ok: false, status: 404, json: async () => ({}) } as Response;
+    });
+    vi.stubGlobal("fetch", fetchMock);
+
+    renderSettingsView({ initialSection: "models" });
+
+    fireEvent.pointerDown(await screen.findByRole("button", { name: /Select model/i }));
+    expect(
+      await screen.findByText("Configure this provider before loading models."),
+    ).toBeInTheDocument();
+    expect(
+      fetchMock.mock.calls.some(([input]) =>
+        String(input).startsWith("/api/settings/provider-models"),
+      ),
+    ).toBe(false);
+  });
+
+  it("prefills manual model ids for configured OAuth providers", async () => {
+    const payload: SettingsPayload = {
+      ...settingsPayload(),
+      agent: {
+        ...settingsPayload().agent,
+        model: "open-codex/gpt-5.5",
+        provider: "openai_codex",
+        resolved_provider: "openai_codex",
+      },
+      model_presets: [
+        {
+          ...settingsPayload().model_presets[0],
+          model: "open-codex/gpt-5.5",
+          provider: "openai_codex",
+        },
+      ],
+      providers: [
+        {
+          name: "openai_codex",
+          label: "OpenAI Codex",
+          configured: true,
+          auth_type: "oauth",
+          api_key_required: false,
+          api_key_hint: null,
+          api_base: null,
+          default_api_base: null,
+          oauth_account: "acct-test",
+          oauth_expires_at: null,
+          oauth_login_supported: true,
+        },
+      ],
+    };
+    const fetchMock = vi.fn(async (input: RequestInfo | URL) => {
+      const url = String(input);
+      if (url === "/api/settings") return jsonResponse(payload);
+      if (url === "/api/settings/cli-apps") {
+        return jsonResponse({ apps: [], installed_count: 0 });
+      }
+      if (url === "/api/settings/mcp-presets") {
+        return jsonResponse({ presets: [], installed_count: 0 });
+      }
+      return { ok: false, status: 404, json: async () => ({}) } as Response;
+    });
+    vi.stubGlobal("fetch", fetchMock);
+
+    renderSettingsView({ initialSection: "models" });
+
+    const modelButtons = await screen.findAllByRole("button", { name: /open-codex\/gpt-5\.5/i });
+    fireEvent.pointerDown(modelButtons[modelButtons.length - 1]);
+    const input = (await screen.findByPlaceholderText("Search or type model ID")) as HTMLInputElement;
+    expect(input.value).toBe("open-codex/gpt-5.5");
+
+    fireEvent.change(input, { target: { value: "openai-codex/gpt-5.5" } });
+    expect(await screen.findByText("“openai-codex/gpt-5.5”")).toBeInTheDocument();
+    expect(
+      fetchMock.mock.calls.some(([input]) =>
+        String(input).startsWith("/api/settings/provider-models"),
+      ),
+    ).toBe(false);
+  });
+
   it("can close the new configuration dialog without trapping the settings page", async () => {
     vi.stubGlobal(
       "fetch",
diff --git a/webui/src/tests/thread-messages.test.tsx b/webui/src/tests/thread-messages.test.tsx
index 5d78bb3f8..8fea32b47 100644
--- a/webui/src/tests/thread-messages.test.tsx
+++ b/webui/src/tests/thread-messages.test.tsx
@@ -151,7 +151,7 @@ describe("ThreadMessages", () => {
     ]);
   });
 
-  it("renders a later tool segment after the visible answer that preceded it", () => {
+  it("moves orphan trailing activity before the completed assistant answer", () => {
     const messages: UIMessage[] = [
       {
         id: "r1",
@@ -182,14 +182,14 @@ describe("ThreadMessages", () => {
 
     expect(units).toHaveLength(3);
     expect(units[0].type === "activity" ? units[0].messages.map((m) => m.id) : []).toEqual(["r1"]);
-    expect(units[1]).toMatchObject({
+    expect(units[1].type === "activity" ? units[1].messages.map((m) => m.id) : []).toEqual(["t1"]);
+    expect(units[2]).toMatchObject({
       type: "message",
       message: {
         id: "a1",
         content: "Let me search the latest data.",
       },
     });
-    expect(units[2].type === "activity" ? units[2].messages.map((m) => m.id) : []).toEqual(["t1"]);
   });
 
   it("only marks the current activity timeline as live while streaming", () => {
@@ -324,7 +324,7 @@ describe("ThreadMessages", () => {
       },
     ];
 
-    const units = buildDisplayUnits(messages);
+    const units = buildDisplayUnits(messages, true);
 
     expect(units).toHaveLength(3);
     expect(units[0].type === "activity" ? units[0].messages.map((m) => m.id) : []).toEqual(["t0"]);
@@ -344,7 +344,7 @@ describe("ThreadMessages", () => {
     expect(answer.compareDocumentPosition(liveActivity) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
   });
 
-  it("keeps late activity after a completed assistant answer", () => {
+  it("moves late activity before a completed assistant answer", () => {
     const messages: UIMessage[] = [
       {
         id: "r1",
@@ -376,21 +376,164 @@ describe("ThreadMessages", () => {
 
     expect(units).toHaveLength(3);
     expect(units[0].type === "activity" ? units[0].messages.map((m) => m.id) : []).toEqual(["r1"]);
-    expect(units[1]).toMatchObject({
+    expect(units[1].type === "activity" ? units[1].messages.map((m) => m.id) : []).toEqual(["t1"]);
+    expect(units[2]).toMatchObject({
       type: "message",
       message: {
         id: "a1",
         content: "Hong Kong is hot today.",
       },
     });
-    expect(units[2].type === "activity" ? units[2].messages.map((m) => m.id) : []).toEqual(["t1"]);
 
     render(<ThreadMessages messages={messages} isStreaming={false} />);
 
     const answer = screen.getByText("Hong Kong is hot today.");
     const laterActivity = screen.getAllByText(/thought/i).at(-1);
     expect(laterActivity).toBeTruthy();
-    expect(answer.compareDocumentPosition(laterActivity!) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+    expect(laterActivity!.compareDocumentPosition(answer) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+  });
+
+  it("does not leave a completed web-search thought below the final answer", () => {
+    const messages: UIMessage[] = [
+      {
+        id: "user",
+        role: "user",
+        content: "最近科隆major开打了，你知道不？",
+        createdAt: 1,
+      },
+      {
+        id: "thought",
+        role: "assistant",
+        content: "",
+        reasoning: "I should verify the current event details.",
+        activitySegmentId: "seg-major",
+        createdAt: 2,
+      },
+      {
+        id: "answer",
+        role: "assistant",
+        content: "知道，IEM Cologne Major 2026 今天开打了。",
+        latencyMs: 18_000,
+        createdAt: 3,
+      },
+      {
+        id: "web",
+        role: "tool",
+        kind: "trace",
+        content: "Searching query: 2026 Cologne Major esports started 科隆 Major 开打了 2026",
+        traces: ["Searching query: 2026 Cologne Major esports started 科隆 Major 开打了 2026"],
+        activitySegmentId: "seg-major",
+        createdAt: 4,
+      },
+    ];
+
+    render(<ThreadMessages messages={messages} isStreaming={false} />);
+
+    const thought = screen.getAllByText(/thought/i).at(-1);
+    const answer = screen.getByText("知道，IEM Cologne Major 2026 今天开打了。");
+    expect(thought).toBeTruthy();
+    expect(thought!.compareDocumentPosition(answer) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+  });
+
+  it("normalizes completed prior turns while the next user turn is streaming", () => {
+    const messages: UIMessage[] = [
+      {
+        id: "thought",
+        role: "assistant",
+        content: "",
+        reasoning: "I should verify the current event details.",
+        activitySegmentId: "seg-major",
+        createdAt: 1,
+      },
+      {
+        id: "answer",
+        role: "assistant",
+        content: "Yep — IEM Cologne Major 2026 is in Cologne.",
+        latencyMs: 20_000,
+        createdAt: 2,
+      },
+      {
+        id: "web",
+        role: "tool",
+        kind: "trace",
+        content: "Searching query: site:counter-strike.net majors 2026",
+        traces: ["Searching query: site:counter-strike.net majors 2026"],
+        activitySegmentId: "seg-major",
+        createdAt: 3,
+      },
+      {
+        id: "next-user",
+        role: "user",
+        content: "看一下目前的赛果，整个表哥",
+        createdAt: 4,
+      },
+    ];
+
+    const units = buildDisplayUnits(messages, true);
+
+    expect(units).toHaveLength(4);
+    expect(units[0].type === "activity" ? units[0].messages.map((m) => m.id) : []).toEqual([
+      "thought",
+    ]);
+    expect(units[1].type === "activity" ? units[1].messages.map((m) => m.id) : []).toEqual([
+      "web",
+    ]);
+    expect(units[2]).toMatchObject({
+      type: "message",
+      message: { id: "answer" },
+    });
+    expect(units[3]).toMatchObject({
+      type: "message",
+      message: { id: "next-user" },
+    });
+  });
+
+  it("orders live turn activity by causal turn sequence before the final answer", () => {
+    const messages: UIMessage[] = [
+      {
+        id: "web-1",
+        role: "tool",
+        kind: "trace",
+        content: "Searching query: 2026 Counter-Strike 2 Major location",
+        traces: ["Searching query: 2026 Counter-Strike 2 Major location"],
+        turnId: "turn-major",
+        turnSeq: 3,
+        activitySegmentId: "seg-1",
+        createdAt: 1,
+      },
+      {
+        id: "answer",
+        role: "assistant",
+        content: "Yep — IEM Cologne Major 2026 is in Cologne.",
+        isStreaming: true,
+        turnId: "turn-major",
+        turnSeq: 84,
+        createdAt: 3,
+      },
+      {
+        id: "web-2",
+        role: "tool",
+        kind: "trace",
+        content: "Searching query: site:counter-strike.net majors 2026",
+        traces: ["Searching query: site:counter-strike.net majors 2026"],
+        turnId: "turn-major",
+        turnSeq: 83,
+        activitySegmentId: "seg-2",
+        createdAt: 2,
+      },
+    ];
+
+    const units = buildDisplayUnits(messages, true);
+
+    expect(units).toHaveLength(2);
+    expect(units[0].type === "activity" ? units[0].messages.map((m) => m.id) : []).toEqual([
+      "web-1",
+      "web-2",
+    ]);
+    expect(units[1]).toMatchObject({
+      type: "message",
+      message: { id: "answer" },
+    });
   });
 
   it("renders interrupted pre-tool text as activity before the final answer", () => {
@@ -509,6 +652,30 @@ describe("ThreadMessages", () => {
     expect(screen.getAllByRole("button", { name: "Copy reply" })).toHaveLength(1);
   });
 
+  it("uses turn ids as activity grouping boundaries when available", () => {
+    const units = buildDisplayUnits([
+      { id: "u1", role: "user", content: "one", turnId: "turn-1", createdAt: 1 },
+      { id: "a1", role: "assistant", content: "answer one", turnId: "turn-1", createdAt: 2 },
+      {
+        id: "t2",
+        role: "tool",
+        kind: "trace",
+        content: "search()",
+        traces: ["search()"],
+        turnId: "turn-2",
+        createdAt: 3,
+      },
+      { id: "a2", role: "assistant", content: "answer two", turnId: "turn-2", createdAt: 4 },
+    ]);
+
+    expect(units.map((unit) => unit.type === "message" ? unit.message.id : "activity")).toEqual([
+      "u1",
+      "a1",
+      "activity",
+      "a2",
+    ]);
+  });
+
   it("computes final assistant copy flags with user-boundary semantics", () => {
     const units = buildDisplayUnits([
       { id: "u1", role: "user", content: "one", createdAt: 1 },
diff --git a/webui/src/tests/thread-shell.test.tsx b/webui/src/tests/thread-shell.test.tsx
index 5db59d9c6..6817b593e 100644
--- a/webui/src/tests/thread-shell.test.tsx
+++ b/webui/src/tests/thread-shell.test.tsx
@@ -78,6 +78,20 @@ function wrap(client: ReturnType<typeof makeClient>, children: ReactNode, modelN
   );
 }
 
+function expectSendMessageWithTurn(
+  client: ReturnType<typeof makeClient>,
+  chatId: string,
+  content: string,
+  options: unknown = undefined,
+) {
+  expect(client.sendMessage).toHaveBeenCalledWith(
+    chatId,
+    content,
+    options,
+    expect.objectContaining({ turnId: expect.any(String) }),
+  );
+}
+
 function session(chatId: string) {
   return {
     key: `websocket:${chatId}`,
@@ -270,6 +284,45 @@ describe("ThreadShell", () => {
     expect(await screen.findByTestId("composer-model-logo-openai_codex")).toBeInTheDocument();
   });
 
+  it("opens model settings from the unconfigured model badge", async () => {
+    const client = makeClient();
+    const settings = modelSettings("openai-codex/gpt-5.1-codex", "openai_codex");
+    settings.agent.has_api_key = false;
+    settings.providers = settings.providers.map((provider) =>
+      provider.name === "openai_codex"
+        ? { ...provider, auth_type: "oauth", configured: false }
+        : provider,
+    );
+    const onOpenModelSettings = vi.fn();
+
+    render(
+      wrap(
+        client,
+        <ThreadShell
+          session={session("unconfigured-model")}
+          title="Unconfigured model"
+          onToggleSidebar={() => {}}
+          settingsSnapshot={settings}
+          onOpenModelSettings={onOpenModelSettings}
+        />,
+        "openai-codex/gpt-5.1-codex",
+      ),
+    );
+
+    const badge = await screen.findByRole("button", { name: "Model not configured" });
+    expect(screen.getByTestId("composer-model-setup-icon")).toBeInTheDocument();
+    expect(screen.queryByTestId("composer-model-logo-openai_codex")).not.toBeInTheDocument();
+    fireEvent.click(badge);
+    expect(onOpenModelSettings).toHaveBeenCalledTimes(1);
+
+    fireEvent.change(screen.getByRole("textbox", { name: "Message input" }), {
+      target: { value: "hello" },
+    });
+    fireEvent.click(screen.getByRole("button", { name: "Configure model" }));
+    expect(onOpenModelSettings).toHaveBeenCalledTimes(2);
+    expect(client.sendMessage).not.toHaveBeenCalled();
+  });
+
   it("keeps image generation controls out of the composer", async () => {
     const client = makeClient();
     const disabledSettings = modelSettings("deepseek-v4-pro", "deepseek");
@@ -339,11 +392,7 @@ describe("ThreadShell", () => {
     fireEvent.click(screen.getByRole("button", { name: "Send message" }));
 
     await waitFor(() =>
-      expect(client.sendMessage).toHaveBeenCalledWith(
-        "chat-a",
-        "persist me across tabs",
-        undefined,
-      ),
+      expectSendMessageWithTurn(client, "chat-a", "persist me across tabs"),
     );
     expect(screen.getByText("persist me across tabs")).toBeInTheDocument();
 
@@ -403,11 +452,7 @@ describe("ThreadShell", () => {
     fireEvent.click(screen.getByRole("button", { name: "Send message" }));
 
     await waitFor(() =>
-      expect(client.sendMessage).toHaveBeenCalledWith(
-        "chat-a",
-        "delete me cleanly",
-        undefined,
-      ),
+      expectSendMessageWithTurn(client, "chat-a", "delete me cleanly"),
     );
     expect(screen.getByText("delete me cleanly")).toBeInTheDocument();
 
@@ -506,11 +551,7 @@ describe("ThreadShell", () => {
     });
 
     await waitFor(() =>
-      expect(client.sendMessage).toHaveBeenCalledWith(
-        "chat-new",
-        "first message should stay",
-        undefined,
-      ),
+      expectSendMessageWithTurn(client, "chat-new", "first message should stay"),
     );
     await waitFor(() =>
       expect(screen.getByText("first message should stay")).toBeInTheDocument(),
@@ -575,7 +616,7 @@ describe("ThreadShell", () => {
     });
 
     await waitFor(() =>
-      expect(client.sendMessage).toHaveBeenCalledWith("chat-new", "/model", undefined),
+      expectSendMessageWithTurn(client, "chat-new", "/model"),
     );
 
     await act(async () => {
@@ -703,11 +744,7 @@ describe("ThreadShell", () => {
     fireEvent.click(screen.getByRole("button", { name: "Send message" }));
 
     await waitFor(() =>
-      expect(client.sendMessage).toHaveBeenCalledWith(
-        "chat-a",
-        "only in chat a",
-        undefined,
-      ),
+      expectSendMessageWithTurn(client, "chat-a", "only in chat a"),
     );
     expect(screen.getByText("only in chat a")).toBeInTheDocument();
 
diff --git a/webui/src/tests/thread-viewport.test.tsx b/webui/src/tests/thread-viewport.test.tsx
index d610d25ec..8f89dd17e 100644
--- a/webui/src/tests/thread-viewport.test.tsx
+++ b/webui/src/tests/thread-viewport.test.tsx
@@ -215,6 +215,42 @@ describe("ThreadViewport", () => {
     });
   });
 
+  it("renders the prompt rail for compact scroll ranges", async () => {
+    const promptMessages = makeLongMessages(3);
+    const { container } = render(
+      <ThreadViewport
+        messages={promptMessages}
+        isStreaming={false}
+        composer={<div />}
+      />,
+    );
+
+    const scroller = container.firstElementChild?.firstElementChild as HTMLElement;
+    Object.defineProperties(scroller, {
+      scrollHeight: { configurable: true, value: 700 },
+      clientHeight: { configurable: true, value: 600 },
+      scrollTop: { configurable: true, value: 0 },
+    });
+
+    const promptEls = Array.from(
+      container.querySelectorAll<HTMLElement>("[data-user-prompt-id]"),
+    );
+    expect(promptEls).toHaveLength(3);
+    promptEls.forEach((el, index) => {
+      Object.defineProperty(el, "offsetTop", {
+        configurable: true,
+        value: index * 50,
+      });
+    });
+
+    await act(async () => {
+      window.dispatchEvent(new Event("resize"));
+      await new Promise<void>((resolve) => window.requestAnimationFrame(() => resolve()));
+    });
+
+    expect(screen.getByLabelText("User prompt navigation")).toBeInTheDocument();
+  });
+
   it("buckets dense prompt rails without rendering every prompt as a marker", async () => {
     const promptMessages = makeLongMessages(100);
     const { container } = render(
diff --git a/webui/src/tests/useNanobotStream.test.tsx b/webui/src/tests/useNanobotStream.test.tsx
index 87c837ca5..21de70fa7 100644
--- a/webui/src/tests/useNanobotStream.test.tsx
+++ b/webui/src/tests/useNanobotStream.test.tsx
@@ -1342,6 +1342,8 @@ describe("useNanobotStream", () => {
     expect(result.current.messages).toHaveLength(1);
     expect(result.current.messages[0].role).toBe("user");
     expect(result.current.messages[0].content).toBe("fine");
+    expect(result.current.messages[0].turnId).toEqual(expect.any(String));
+    expect(result.current.messages[0].turnPhase).toBe("user");
   });
 
   it("attaches assistant media_urls to complete messages", () => {
@@ -1482,7 +1484,10 @@ describe("useNanobotStream", () => {
       "chat-img",
       "draw a square icon",
       undefined,
-      { imageGeneration: { enabled: true, aspect_ratio: "1:1" } },
+      expect.objectContaining({
+        imageGeneration: { enabled: true, aspect_ratio: "1:1" },
+        turnId: expect.any(String),
+      }),
     );
   });