From 4dd9732a94e757d5403fe3e1f3cc673559bbd7c2 Mon Sep 17 00:00:00 2001
From: Brooklyn Nicholson <brooklyn.bb.nicholson@gmail.com>
Date: Mon, 11 May 2026 16:34:25 -0400
Subject: [PATCH] feat(desktop): hoisted todo widget, JSON tool summaries,
 history grouping & timer fixes

- Hoist todo to first-class widget (shadcn checkboxes, brand colors, no
  tool-accordion). Header derives label from active task; non-active rows fade.
- Replace raw JSON dumps with structured key/value summaries via
  formatToolResultSummary; nested error extraction for clearer failures.
- Fix loaded-session grouping: stitch interleaved assistant/tool iterations
  into one bubble instead of orphaned synthetic messages.
- Stable tool/thinking timers via keyed registry so unmount/scroll doesn't
  reset elapsed counts; gate "running" on real live thread state.
- Reorganize chat-only assistant-ui components under components/chat/.
---
 apps/desktop/src/app/artifacts/index.tsx      |  22 +-
 apps/desktop/src/app/chat/composer/index.tsx  |  63 ++--
 .../app/chat/sidebar/session-actions-menu.tsx |  14 +-
 .../app/session/hooks/use-message-stream.ts   |  19 +-
 .../src/app/shell/statusbar-controls.tsx      |  18 +-
 .../components/assistant-ui/activity-timer.ts |  36 --
 .../components/assistant-ui/attachment.tsx    |   6 -
 .../assistant-ui/directive-text.tsx           |  10 +-
 .../components/assistant-ui/markdown-text.tsx |   6 +-
 .../src/components/assistant-ui/reasoning.tsx |  14 -
 .../assistant-ui/streaming.test.tsx           | 142 +++++++-
 .../src/components/assistant-ui/thread.tsx    |  45 +--
 .../src/components/assistant-ui/todo-tool.tsx |  94 +++++
 .../components/assistant-ui/tool-fallback.tsx | 198 +++++------
 .../components/assistant-ui/tool-group.tsx    |   9 -
 .../activity-timer-text.tsx                   |   0
 .../components/chat/activity-timer.test.tsx   |  43 +++
 .../src/components/chat/activity-timer.ts     |  52 +++
 .../compact-markdown.tsx                      |   0
 .../{assistant-ui => chat}/disclosure-row.tsx |   0
 .../generated-image-context.tsx               |   0
 .../image-generation-placeholder.tsx          |   0
 .../{assistant-ui => chat}/intro-copy.jsonl   |   0
 .../{assistant-ui => chat}/intro.tsx          |   0
 .../preview-attachment.tsx                    |   0
 .../shiki-highlighter.tsx                     |   0
 .../{assistant-ui => chat}/zoomable-image.tsx |   0
 apps/desktop/src/components/model-picker.tsx  |   4 +-
 apps/desktop/src/lib/chat-messages.test.ts    | 104 ++++++
 apps/desktop/src/lib/chat-messages.ts         | 134 +++++--
 apps/desktop/src/lib/todos.test.ts            |  35 ++
 apps/desktop/src/lib/todos.ts                 |  38 ++
 .../src/lib/tool-result-summary.test.ts       | 108 ++++++
 apps/desktop/src/lib/tool-result-summary.ts   | 326 ++++++++++++++++++
 34 files changed, 1234 insertions(+), 306 deletions(-)
 delete mode 100644 apps/desktop/src/components/assistant-ui/activity-timer.ts
 delete mode 100644 apps/desktop/src/components/assistant-ui/attachment.tsx
 delete mode 100644 apps/desktop/src/components/assistant-ui/reasoning.tsx
 create mode 100644 apps/desktop/src/components/assistant-ui/todo-tool.tsx
 delete mode 100644 apps/desktop/src/components/assistant-ui/tool-group.tsx
 rename apps/desktop/src/components/{assistant-ui => chat}/activity-timer-text.tsx (100%)
 create mode 100644 apps/desktop/src/components/chat/activity-timer.test.tsx
 create mode 100644 apps/desktop/src/components/chat/activity-timer.ts
 rename apps/desktop/src/components/{assistant-ui => chat}/compact-markdown.tsx (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/disclosure-row.tsx (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/generated-image-context.tsx (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/image-generation-placeholder.tsx (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/intro-copy.jsonl (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/intro.tsx (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/preview-attachment.tsx (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/shiki-highlighter.tsx (100%)
 rename apps/desktop/src/components/{assistant-ui => chat}/zoomable-image.tsx (100%)
 create mode 100644 apps/desktop/src/lib/todos.test.ts
 create mode 100644 apps/desktop/src/lib/todos.ts
 create mode 100644 apps/desktop/src/lib/tool-result-summary.test.ts
 create mode 100644 apps/desktop/src/lib/tool-result-summary.ts

diff --git a/apps/desktop/src/app/artifacts/index.tsx b/apps/desktop/src/app/artifacts/index.tsx
index 45219522c5..ba9697518a 100644
--- a/apps/desktop/src/app/artifacts/index.tsx
+++ b/apps/desktop/src/app/artifacts/index.tsx
@@ -2,7 +2,7 @@ import type * as React from 'react'
 import { useCallback, useEffect, useMemo, useState } from 'react'
 import { useNavigate } from 'react-router-dom'
 
-import { ZoomableImage } from '@/components/assistant-ui/zoomable-image'
+import { ZoomableImage } from '@/components/chat/zoomable-image'
 import { PageLoader } from '@/components/page-loader'
 import { Button } from '@/components/ui/button'
 import { CopyButton } from '@/components/ui/copy-button'
@@ -786,9 +786,6 @@ function ArtifactImageCard({ artifact, failedImage, onImageError, onOpenChat }:
   )
 }
 
-const CELL_ACTION_CLASS =
-  'flex h-full w-full min-w-0 items-center gap-2 px-2.5 py-1.5 text-left text-sm leading-snug font-medium text-foreground/90 no-underline transition-colors hover:text-foreground hover:underline'
-
 // Single click target for any row cell. External URLs render as <ExternalLink>;
 // local actions render as <button>. Padding lives here, NOT on the <td>, so
 // the entire cell area is hoverable and clickable in both branches.
@@ -805,14 +802,27 @@ function ArtifactCellAction({
 }) {
   if (href) {
     return (
-      <ExternalLink className={CELL_ACTION_CLASS} href={href} showExternalIcon={false} title={title}>
+      <ExternalLink
+        className="flex h-full w-full min-w-0 items-center gap-2 px-2.5 py-1.5 text-left text-sm leading-snug font-medium text-foreground/90 no-underline transition-colors hover:text-foreground hover:underline"
+        href={href}
+        showExternalIcon={false}
+        title={title}
+      >
         {children}
       </ExternalLink>
     )
   }
 
   return (
-    <button className={cn(CELL_ACTION_CLASS, 'cursor-pointer')} onClick={onClick} title={title} type="button">
+    <button
+      className={cn(
+        'flex h-full w-full min-w-0 items-center gap-2 px-2.5 py-1.5 text-left text-sm leading-snug font-medium text-foreground/90 no-underline transition-colors hover:text-foreground hover:underline',
+        'cursor-pointer'
+      )}
+      onClick={onClick}
+      title={title}
+      type="button"
+    >
       {children}
     </button>
   )
diff --git a/apps/desktop/src/app/chat/composer/index.tsx b/apps/desktop/src/app/chat/composer/index.tsx
index 6265b3d2da..06959bddf4 100644
--- a/apps/desktop/src/app/chat/composer/index.tsx
+++ b/apps/desktop/src/app/chat/composer/index.tsx
@@ -50,9 +50,6 @@ import type { ChatBarProps } from './types'
 import { UrlDialog } from './url-dialog'
 import { VoiceActivity, VoicePlaybackActivity } from './voice-activity'
 
-const COMPOSER_SHELL_CLASS =
-  'group/composer absolute bottom-0 left-1/2 z-30 w-[min(var(--composer-width),calc(100%-2rem))] max-w-full -translate-x-1/2 rounded-2xl pt-2 pb-[var(--composer-shell-pad-block-end)]'
-
 function extractClipboardImageBlobs(clipboard: DataTransfer): Blob[] {
   const blobs: Blob[] = []
   const seen = new Set<Blob>()
@@ -111,21 +108,6 @@ function extractClipboardImageBlobs(clipboard: DataTransfer): Blob[] {
 
 const COMPOSER_STACK_BREAKPOINT_PX = 320
 
-const COMPOSER_SCROLLED_DIM_CLASS =
-  'opacity-30 group-hover/composer:opacity-100 group-focus-within/composer:opacity-100'
-
-const COMPOSER_FROST_CLASS = cn(
-  'pointer-events-none absolute inset-0 -z-10 rounded-[inherit]',
-  'bg-[color-mix(in_srgb,var(--dt-card)_72%,transparent)]',
-  'backdrop-blur-[0.75rem] backdrop-saturate-[1.12]',
-  '[-webkit-backdrop-filter:blur(0.75rem)_saturate(1.12)]',
-  'transition-[background-color] duration-150 ease-out',
-  'group-data-[thread-scrolled-up]/composer:bg-[color-mix(in_srgb,var(--dt-card)_48%,transparent)]',
-  'group-focus-within/composer:bg-[var(--dt-card)]',
-  'group-focus-within/composer:[backdrop-filter:none]',
-  'group-focus-within/composer:[-webkit-backdrop-filter:none]'
-)
-
 const COMPOSER_GLASS = {
   fadeBackground: 'linear-gradient(to bottom, transparent, color-mix(in srgb, var(--dt-background) 10%, transparent))',
   liquidKey: ['standard', '0.950', '0.072', '0', '46', '0.00', '128'].join(':'),
@@ -921,7 +903,7 @@ export function ChatBar({
     <>
       <ComposerPrimitive.Unstable_TriggerPopoverRoot>
         <ComposerPrimitive.Root
-          className={COMPOSER_SHELL_CLASS}
+          className="group/composer absolute bottom-0 left-1/2 z-30 w-[min(var(--composer-width),calc(100%-2rem))] max-w-full -translate-x-1/2 rounded-2xl pt-2 pb-[var(--composer-shell-pad-block-end)]"
           data-drag-active={dragActive ? '' : undefined}
           data-slot="composer-root"
           data-thread-scrolled-up={scrolledUp ? '' : undefined}
@@ -955,7 +937,9 @@ export function ChatBar({
             <div
               className={cn(
                 'composer-liquid-shell-wrap absolute -inset-px isolate overflow-hidden rounded-[calc(var(--radius-2xl)+1px)] transition-opacity duration-200 ease-out',
-                scrolledUp ? COMPOSER_SCROLLED_DIM_CLASS : 'opacity-100'
+                scrolledUp
+                  ? 'opacity-30 group-hover/composer:opacity-100 group-focus-within/composer:opacity-100'
+                  : 'opacity-100'
               )}
               data-glass-frame="true"
               data-show-library-rims={COMPOSER_GLASS.showLibraryRims ? 'true' : undefined}
@@ -990,7 +974,20 @@ export function ChatBar({
               data-slot="composer-surface"
               ref={composerSurfaceRef}
             >
-              <div aria-hidden className={COMPOSER_FROST_CLASS} />
+              <div
+                aria-hidden
+                className={cn(
+                  'pointer-events-none absolute inset-0 -z-10 rounded-[inherit]',
+                  'bg-[color-mix(in_srgb,var(--dt-card)_72%,transparent)]',
+                  'backdrop-blur-[0.75rem] backdrop-saturate-[1.12]',
+                  '[-webkit-backdrop-filter:blur(0.75rem)_saturate(1.12)]',
+                  'transition-[background-color] duration-150 ease-out',
+                  'group-data-[thread-scrolled-up]/composer:bg-[color-mix(in_srgb,var(--dt-card)_48%,transparent)]',
+                  'group-focus-within/composer:bg-[var(--dt-card)]',
+                  'group-focus-within/composer:[backdrop-filter:none]',
+                  'group-focus-within/composer:[-webkit-backdrop-filter:none]'
+                )}
+              />
               {dragActive && (
                 <div
                   aria-hidden
@@ -1002,7 +999,9 @@ export function ChatBar({
               <div
                 className={cn(
                   'relative z-1 flex min-h-0 w-full flex-col gap-(--composer-row-gap) overflow-hidden rounded-[inherit] px-(--composer-surface-pad-x) py-(--composer-surface-pad-y) transition-opacity duration-200 ease-out',
-                  scrolledUp ? COMPOSER_SCROLLED_DIM_CLASS : 'opacity-100'
+                  scrolledUp
+                    ? 'opacity-30 group-hover/composer:opacity-100 group-focus-within/composer:opacity-100'
+                    : 'opacity-100'
                 )}
                 data-slot="composer-fade"
               >
@@ -1042,11 +1041,27 @@ export function ChatBar({
 export function ChatBarFallback() {
   return (
     <div
-      className={cn(COMPOSER_SHELL_CLASS, 'bg-linear-to-b from-transparent to-background/55')}
+      className={cn(
+        'group/composer absolute bottom-0 left-1/2 z-30 w-[min(var(--composer-width),calc(100%-2rem))] max-w-full -translate-x-1/2 rounded-2xl pt-2 pb-[var(--composer-shell-pad-block-end)]',
+        'bg-linear-to-b from-transparent to-background/55'
+      )}
       data-slot="composer-root"
     >
       <div className="composer-fallback-surface relative isolate h-(--composer-fallback-height) w-full rounded-[inherit] border border-[color-mix(in_srgb,var(--dt-composer-ring)_calc(18%*var(--composer-ring-strength)),var(--dt-input))] shadow-composer">
-        <div aria-hidden className={COMPOSER_FROST_CLASS} />
+        <div
+          aria-hidden
+          className={cn(
+            'pointer-events-none absolute inset-0 -z-10 rounded-[inherit]',
+            'bg-[color-mix(in_srgb,var(--dt-card)_72%,transparent)]',
+            'backdrop-blur-[0.75rem] backdrop-saturate-[1.12]',
+            '[-webkit-backdrop-filter:blur(0.75rem)_saturate(1.12)]',
+            'transition-[background-color] duration-150 ease-out',
+            'group-data-[thread-scrolled-up]/composer:bg-[color-mix(in_srgb,var(--dt-card)_48%,transparent)]',
+            'group-focus-within/composer:bg-[var(--dt-card)]',
+            'group-focus-within/composer:[backdrop-filter:none]',
+            'group-focus-within/composer:[-webkit-backdrop-filter:none]'
+          )}
+        />
       </div>
     </div>
   )
diff --git a/apps/desktop/src/app/chat/sidebar/session-actions-menu.tsx b/apps/desktop/src/app/chat/sidebar/session-actions-menu.tsx
index d5217748a3..5c58e1b10f 100644
--- a/apps/desktop/src/app/chat/sidebar/session-actions-menu.tsx
+++ b/apps/desktop/src/app/chat/sidebar/session-actions-menu.tsx
@@ -50,7 +50,6 @@ export function SessionActionsMenu({
   align = 'end',
   sideOffset = 6
 }: SessionActionsMenuProps) {
-  const itemClass = 'gap-2.5 text-foreground focus:bg-accent [&_svg]:size-4'
   const [renameOpen, setRenameOpen] = useState(false)
 
   return (
@@ -59,7 +58,7 @@ export function SessionActionsMenu({
         <DropdownMenuTrigger asChild>{children}</DropdownMenuTrigger>
         <DropdownMenuContent align={align} aria-label={`Actions for ${title}`} className="w-44" sideOffset={sideOffset}>
           <DropdownMenuItem
-            className={itemClass}
+            className="gap-2.5 text-foreground focus:bg-accent [&_svg]:size-4"
             disabled={!onPin}
             onSelect={() => {
               triggerHaptic('selection')
@@ -71,14 +70,14 @@ export function SessionActionsMenu({
           </DropdownMenuItem>
           <CopyButton
             appearance="menu-item"
-            className={itemClass}
+            className="gap-2.5 text-foreground focus:bg-accent [&_svg]:size-4"
             disabled={!sessionId}
             errorMessage="Could not copy session ID"
             label="Copy ID"
             text={sessionId}
           />
           <DropdownMenuItem
-            className={itemClass}
+            className="gap-2.5 text-foreground focus:bg-accent [&_svg]:size-4"
             disabled={!sessionId}
             onSelect={() => {
               triggerHaptic('selection')
@@ -89,7 +88,7 @@ export function SessionActionsMenu({
             <span>Export</span>
           </DropdownMenuItem>
           <DropdownMenuItem
-            className={itemClass}
+            className="gap-2.5 text-foreground focus:bg-accent [&_svg]:size-4"
             disabled={!sessionId}
             onSelect={() => {
               triggerHaptic('selection')
@@ -101,7 +100,10 @@ export function SessionActionsMenu({
           </DropdownMenuItem>
           <DropdownMenuSeparator className="my-3" />
           <DropdownMenuItem
-            className={cn(itemClass, 'text-destructive focus:text-destructive')}
+            className={cn(
+              'gap-2.5 text-foreground focus:bg-accent [&_svg]:size-4',
+              'text-destructive focus:text-destructive'
+            )}
             disabled={!onDelete}
             onSelect={() => {
               triggerHaptic('warning')
diff --git a/apps/desktop/src/app/session/hooks/use-message-stream.ts b/apps/desktop/src/app/session/hooks/use-message-stream.ts
index 5f0e52ee62..54cefc1be2 100644
--- a/apps/desktop/src/app/session/hooks/use-message-stream.ts
+++ b/apps/desktop/src/app/session/hooks/use-message-stream.ts
@@ -62,6 +62,15 @@ interface QueuedStreamDeltas {
 
 const STREAM_DELTA_FLUSH_MS = 16
 
+// Anonymous progress events that carry todos but no name still belong to the
+// todo stream; named todo events are obviously routed there too.
+function toTodoPayload(payload: GatewayEventPayload | undefined): GatewayEventPayload | undefined {
+  if (!payload) {return undefined}
+  const isTodo = payload.name === 'todo' || (!payload.name && Object.hasOwn(payload, 'todos'))
+
+  return isTodo ? { ...payload, name: 'todo', tool_id: payload.tool_id || 'todo-live' } : undefined
+}
+
 export function useMessageStream({
   activeSessionIdRef,
   hydrateFromStoredSession,
@@ -552,17 +561,13 @@ export function useMessageStream({
           setCurrentUsage(current => ({ ...current, ...payload.usage }))
         }
       } else if (event.type === 'tool.start' || event.type === 'tool.progress' || event.type === 'tool.generating') {
-        if (!sessionId) {
-          return
-        }
-
+        if (!sessionId) {return}
         flushQueuedDeltas(sessionId)
-
-        upsertToolCall(sessionId, payload, 'running')
+        upsertToolCall(sessionId, toTodoPayload(payload) ?? payload, 'running')
       } else if (event.type === 'tool.complete') {
         if (sessionId) {
           flushQueuedDeltas(sessionId)
-          upsertToolCall(sessionId, payload, 'complete')
+          upsertToolCall(sessionId, toTodoPayload(payload) ?? payload, 'complete')
         }
 
         if (typeof payload?.inline_diff === 'string' && payload.inline_diff.trim()) {
diff --git a/apps/desktop/src/app/shell/statusbar-controls.tsx b/apps/desktop/src/app/shell/statusbar-controls.tsx
index 0c426e2379..6ffad250e1 100644
--- a/apps/desktop/src/app/shell/statusbar-controls.tsx
+++ b/apps/desktop/src/app/shell/statusbar-controls.tsx
@@ -43,9 +43,6 @@ interface StatusbarControlsProps extends ComponentProps<'footer'> {
   items?: readonly StatusbarItem[]
 }
 
-const statusbarItemClass =
-  'inline-flex h-full cursor-pointer items-center gap-1 rounded-none px-1.5 text-[0.68rem] text-muted-foreground/95 transition-colors hover:bg-(--chrome-action-hover) hover:text-foreground disabled:cursor-default disabled:opacity-45'
-
 export function StatusbarControls({ className, leftItems = [], items = [], ...props }: StatusbarControlsProps) {
   const navigate = useNavigate()
 
@@ -91,7 +88,10 @@ function StatusbarItemView({ item, navigate }: { item: StatusbarItem; navigate:
       <DropdownMenu>
         <DropdownMenuTrigger asChild>
           <button
-            className={cn(statusbarItemClass, item.className)}
+            className={cn(
+              'inline-flex h-full cursor-pointer items-center gap-1 rounded-none px-1.5 text-[0.68rem] text-muted-foreground/95 transition-colors hover:bg-(--chrome-action-hover) hover:text-foreground disabled:cursor-default disabled:opacity-45',
+              item.className
+            )}
             disabled={item.disabled}
             title={title}
             type="button"
@@ -162,7 +162,10 @@ function StatusbarItemView({ item, navigate }: { item: StatusbarItem; navigate:
   if (item.href || item.variant === 'link') {
     return (
       <a
-        className={cn(statusbarItemClass, item.className)}
+        className={cn(
+          'inline-flex h-full cursor-pointer items-center gap-1 rounded-none px-1.5 text-[0.68rem] text-muted-foreground/95 transition-colors hover:bg-(--chrome-action-hover) hover:text-foreground disabled:cursor-default disabled:opacity-45',
+          item.className
+        )}
         href={item.href}
         rel="noreferrer"
         target="_blank"
@@ -175,7 +178,10 @@ function StatusbarItemView({ item, navigate }: { item: StatusbarItem; navigate:
 
   return (
     <button
-      className={cn(statusbarItemClass, item.className)}
+      className={cn(
+        'inline-flex h-full cursor-pointer items-center gap-1 rounded-none px-1.5 text-[0.68rem] text-muted-foreground/95 transition-colors hover:bg-(--chrome-action-hover) hover:text-foreground disabled:cursor-default disabled:opacity-45',
+        item.className
+      )}
       disabled={item.disabled}
       onClick={() => {
         if (item.to) {
diff --git a/apps/desktop/src/components/assistant-ui/activity-timer.ts b/apps/desktop/src/components/assistant-ui/activity-timer.ts
deleted file mode 100644
index 73a9479628..0000000000
--- a/apps/desktop/src/components/assistant-ui/activity-timer.ts
+++ /dev/null
@@ -1,36 +0,0 @@
-import { useEffect, useRef, useState } from 'react'
-
-const ELAPSED_TICK_MS = 1000
-
-export function formatElapsed(seconds: number): string {
-  if (seconds < 60) {
-    return `${seconds}s`
-  }
-
-  const minutes = Math.floor(seconds / 60)
-  const remainder = seconds % 60
-
-  return `${minutes}:${String(remainder).padStart(2, '0')}`
-}
-
-export function useElapsedSeconds(active = true): number {
-  const startedAt = useRef(Date.now())
-  const [elapsed, setElapsed] = useState(0)
-
-  useEffect(() => {
-    if (!active) {
-      return
-    }
-
-    const update = () => {
-      setElapsed(Math.max(0, Math.floor((Date.now() - startedAt.current) / 1000)))
-    }
-
-    update()
-    const id = window.setInterval(update, ELAPSED_TICK_MS)
-
-    return () => window.clearInterval(id)
-  }, [active])
-
-  return elapsed
-}
diff --git a/apps/desktop/src/components/assistant-ui/attachment.tsx b/apps/desktop/src/components/assistant-ui/attachment.tsx
deleted file mode 100644
index 3a1362244b..0000000000
--- a/apps/desktop/src/components/assistant-ui/attachment.tsx
+++ /dev/null
@@ -1,6 +0,0 @@
-'use client'
-
-// Minimal stubs — attachment upload not wired in the desktop app yet.
-export const ComposerAddAttachment = () => null
-export const ComposerAttachments = () => null
-export const UserMessageAttachments = () => null
diff --git a/apps/desktop/src/components/assistant-ui/directive-text.tsx b/apps/desktop/src/components/assistant-ui/directive-text.tsx
index 91c04f06ce..03937c5ca3 100644
--- a/apps/desktop/src/components/assistant-ui/directive-text.tsx
+++ b/apps/desktop/src/components/assistant-ui/directive-text.tsx
@@ -5,7 +5,7 @@ import type { TextMessagePartComponent, TextMessagePartProps } from '@assistant-
 import type { FC } from 'react'
 import { Fragment, useEffect, useMemo, useState } from 'react'
 
-import { ZoomableImage } from '@/components/assistant-ui/zoomable-image'
+import { ZoomableImage } from '@/components/chat/zoomable-image'
 import { extractEmbeddedImages } from '@/lib/embedded-images'
 
 const HERMES_REF_TYPES = ['file', 'folder', 'url', 'image', 'tool', 'line'] as const
@@ -42,8 +42,6 @@ const ICON_PATHS: Record<HermesRefType, string[]> = {
 
 const ICON_FALLBACK = ['M8 12a4 4 0 1 0 8 0a4 4 0 1 0 -8 0', 'M16 12v1.5a2.5 2.5 0 0 0 5 0v-1.5a9 9 0 1 0 -5.5 8.28']
 
-const ICON_CLASS = 'size-3 shrink-0 opacity-80'
-
 const SVG_ATTRS =
   'xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"'
 
@@ -55,12 +53,12 @@ export function directiveIconSvg(type: string) {
     .map(d => `<path d="${d}"/>`)
     .join('')
 
-  return `<svg ${SVG_ATTRS} class="${ICON_CLASS}">${inner}</svg>`
+  return `<svg ${SVG_ATTRS} class="size-3 shrink-0 opacity-80">${inner}</svg>`
 }
 
 export function directiveIconElement(type: string) {
   const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg')
-  svg.setAttribute('class', ICON_CLASS)
+  svg.setAttribute('class', 'size-3 shrink-0 opacity-80')
   svg.setAttribute('fill', 'none')
   svg.setAttribute('stroke', 'currentColor')
   svg.setAttribute('stroke-linecap', 'round')
@@ -80,7 +78,7 @@ export function directiveIconElement(type: string) {
 
 const DirectiveIcon: FC<{ type: string }> = ({ type }) => (
   <svg
-    className={ICON_CLASS}
+    className="size-3 shrink-0 opacity-80"
     fill="none"
     stroke="currentColor"
     strokeLinecap="round"
diff --git a/apps/desktop/src/components/assistant-ui/markdown-text.tsx b/apps/desktop/src/components/assistant-ui/markdown-text.tsx
index 7b67491237..e3b911b89d 100644
--- a/apps/desktop/src/components/assistant-ui/markdown-text.tsx
+++ b/apps/desktop/src/components/assistant-ui/markdown-text.tsx
@@ -9,9 +9,9 @@ import {
 import { code } from '@streamdown/code'
 import { type ComponentProps, memo, useEffect, useMemo, useState } from 'react'
 
-import { PreviewAttachment } from '@/components/assistant-ui/preview-attachment'
-import { SyntaxHighlighter } from '@/components/assistant-ui/shiki-highlighter'
-import { ZoomableImage } from '@/components/assistant-ui/zoomable-image'
+import { PreviewAttachment } from '@/components/chat/preview-attachment'
+import { SyntaxHighlighter } from '@/components/chat/shiki-highlighter'
+import { ZoomableImage } from '@/components/chat/zoomable-image'
 import { CopyButton } from '@/components/ui/copy-button'
 import { normalizeExternalUrl, openExternalLink, PrettyLink } from '@/lib/external-link'
 import { isLikelyProseCodeBlock, sanitizeLanguageTag } from '@/lib/markdown-code'
diff --git a/apps/desktop/src/components/assistant-ui/reasoning.tsx b/apps/desktop/src/components/assistant-ui/reasoning.tsx
deleted file mode 100644
index 8804d1d6a2..0000000000
--- a/apps/desktop/src/components/assistant-ui/reasoning.tsx
+++ /dev/null
@@ -1,14 +0,0 @@
-'use client'
-
-// Minimal reasoning stubs — not surfaced by the Hermes gateway yet.
-import { type ReactNode } from 'react'
-
-export const ReasoningRoot = ({ children }: { children: ReactNode; defaultOpen?: boolean }) => (
-  <div className="my-1">{children}</div>
-)
-export const ReasoningTrigger = (_props: { active?: boolean }) => null
-export const ReasoningContent = ({ children, 'aria-busy': _busy }: { children: ReactNode; 'aria-busy'?: boolean }) => (
-  <div className="border-l-2 border-border pl-3 text-xs text-muted-foreground">{children}</div>
-)
-export const ReasoningText = ({ children }: { children: ReactNode }) => <div>{children}</div>
-export const Reasoning = (_props: object) => null
diff --git a/apps/desktop/src/components/assistant-ui/streaming.test.tsx b/apps/desktop/src/components/assistant-ui/streaming.test.tsx
index 0fc83c23dd..bd7571abbb 100644
--- a/apps/desktop/src/components/assistant-ui/streaming.test.tsx
+++ b/apps/desktop/src/components/assistant-ui/streaming.test.tsx
@@ -1,5 +1,5 @@
 import { AssistantRuntimeProvider, type ThreadMessage, useExternalStoreRuntime } from '@assistant-ui/react'
-import { act, fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { act, fireEvent, render, screen, waitFor, within } from '@testing-library/react'
 import { useEffect, useState } from 'react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
@@ -119,6 +119,67 @@ function assistantMultiReasoningMessage(texts: string[]): ThreadMessage {
   } as ThreadMessage
 }
 
+function assistantTodoMessage(
+  todos: Array<{ content: string; id: string; status: 'cancelled' | 'completed' | 'in_progress' | 'pending' }>,
+  running = true
+): ThreadMessage {
+  const suffix = todos.map(todo => `${todo.id}:${todo.status}`).join('|') || 'empty'
+
+  return {
+    id: `assistant-todo-${running ? 'running' : 'done'}-${suffix}`,
+    role: 'assistant',
+    content: [
+      {
+        type: 'tool-call',
+        toolCallId: 'todo-1',
+        toolName: 'todo',
+        args: { todos },
+        argsText: JSON.stringify({ todos }),
+        ...(running ? {} : { result: { todos } })
+      }
+    ],
+    status: running ? { type: 'running' } : { type: 'complete', reason: 'stop' },
+    createdAt,
+    metadata: {
+      unstable_state: null,
+      unstable_annotations: [],
+      unstable_data: [],
+      steps: [],
+      custom: {}
+    }
+  } as ThreadMessage
+}
+
+function assistantReasoningTodoMessage(
+  todos: Array<{ content: string; id: string; status: 'cancelled' | 'completed' | 'in_progress' | 'pending' }>
+): ThreadMessage {
+  return {
+    id: 'assistant-reasoning-todo-1',
+    role: 'assistant',
+    content: [
+      { type: 'reasoning', text: 'Let me make a quick todo list.' },
+      {
+        type: 'tool-call',
+        toolCallId: 'todo-1',
+        toolName: 'todo',
+        args: { todos },
+        argsText: JSON.stringify({ todos }),
+        result: { todos }
+      },
+      { type: 'text', text: 'Done — fake list created.' }
+    ],
+    status: { type: 'complete', reason: 'stop' },
+    createdAt,
+    metadata: {
+      unstable_state: null,
+      unstable_annotations: [],
+      unstable_data: [],
+      steps: [],
+      custom: {}
+    }
+  } as ThreadMessage
+}
+
 function StreamingHarness() {
   const [messages, setMessages] = useState<ThreadMessage[]>([userMessage()])
   const [isRunning, setIsRunning] = useState(true)
@@ -157,6 +218,20 @@ function StreamingHarness() {
   )
 }
 
+function TodoHarness({ message }: { message: ThreadMessage }) {
+  const runtime = useExternalStoreRuntime<ThreadMessage>({
+    messages: [message],
+    isRunning: message.status?.type === 'running',
+    onNew: async () => {}
+  })
+
+  return (
+    <AssistantRuntimeProvider runtime={runtime}>
+      <Thread />
+    </AssistantRuntimeProvider>
+  )
+}
+
 function ReasoningHarness() {
   const runtime = useExternalStoreRuntime<ThreadMessage>({
     messages: [assistantReasoningMessage(' The user is asking what this file is.')],
@@ -298,4 +373,69 @@ describe('assistant-ui streaming renderer', () => {
     expect(reasoningParts[0]?.textContent).toBe('First thought.')
     expect(reasoningParts[1]?.textContent).toBe('Second thought.')
   })
+
+  it('renders live todo rows during a running turn', () => {
+    const { container } = render(
+      <TodoHarness
+        message={assistantTodoMessage([
+          { content: 'Gather ingredients', id: 'prep', status: 'completed' },
+          { content: 'Boil water', id: 'boil', status: 'in_progress' }
+        ])}
+      />
+    )
+
+    const ui = within(container)
+
+    expect(container.querySelector('[data-slot="aui_todo-hoisted"]')).toBeTruthy()
+    expect(ui.getAllByText('Boil water').length).toBeGreaterThan(0)
+    expect(ui.getByText('Gather ingredients')).toBeTruthy()
+    expect(ui.queryByText(/pending/i)).toBeNull()
+    expect(ui.queryByRole('button', { name: /todo/i })).toBeNull()
+  })
+
+  it('renders archived todos after turn completion regardless of pending state', () => {
+    const first = render(
+      <TodoHarness
+        message={assistantTodoMessage([
+          { content: 'Boil water', id: 'boil', status: 'pending' }
+        ], false)}
+      />
+    )
+
+    const ui = within(first.container)
+
+    expect(ui.getAllByText('Boil water').length).toBeGreaterThan(0)
+
+    first.unmount()
+
+    const second = render(
+      <TodoHarness
+        message={assistantTodoMessage([
+          { content: 'Serve latte', id: 'serve', status: 'completed' }
+        ], false)}
+      />
+    )
+
+    const archivedUi = within(second.container)
+
+    expect(archivedUi.getAllByText('Serve latte').length).toBeGreaterThan(0)
+  })
+
+  it('hoists todo outside the thinking disclosure when reasoning is present', () => {
+    const { container } = render(
+      <TodoHarness
+        message={assistantReasoningTodoMessage([
+          { content: 'Buy oats', id: 'oats', status: 'completed' },
+          { content: "Reply to Sam's email", id: 'email', status: 'in_progress' }
+        ])}
+      />
+    )
+
+    const todoPanel = container.querySelector('[data-slot="aui_todo-hoisted"]')
+    const thinkingDisclosure = container.querySelector('[data-slot="aui_thinking-disclosure"]')
+
+    expect(todoPanel).toBeTruthy()
+    expect(thinkingDisclosure).toBeTruthy()
+    expect(Boolean(thinkingDisclosure?.contains(todoPanel as Node))).toBe(false)
+  })
 })
diff --git a/apps/desktop/src/components/assistant-ui/thread.tsx b/apps/desktop/src/components/assistant-ui/thread.tsx
index 06ff2082a9..1e8f2cd8e7 100644
--- a/apps/desktop/src/components/assistant-ui/thread.tsx
+++ b/apps/desktop/src/components/assistant-ui/thread.tsx
@@ -14,18 +14,19 @@ import { useStore } from '@nanostores/react'
 import { type FC, type ReactNode, useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { StickToBottom, useStickToBottomContext } from 'use-stick-to-bottom'
 
-import { useElapsedSeconds } from '@/components/assistant-ui/activity-timer'
-import { ActivityTimerText } from '@/components/assistant-ui/activity-timer-text'
 import { ClarifyTool } from '@/components/assistant-ui/clarify-tool'
 import { DirectiveContent, DirectiveText } from '@/components/assistant-ui/directive-text'
-import { DisclosureRow } from '@/components/assistant-ui/disclosure-row'
-import { GeneratedImageProvider, useGeneratedImageContext } from '@/components/assistant-ui/generated-image-context'
-import { ImageGenerationPlaceholder } from '@/components/assistant-ui/image-generation-placeholder'
-import { Intro, type IntroProps } from '@/components/assistant-ui/intro'
 import { MarkdownText } from '@/components/assistant-ui/markdown-text'
-import { PreviewAttachment } from '@/components/assistant-ui/preview-attachment'
+import { HoistedTodoPanel, todosFromMessageContent } from '@/components/assistant-ui/todo-tool'
 import { ToolFallback } from '@/components/assistant-ui/tool-fallback'
 import { TooltipIconButton } from '@/components/assistant-ui/tooltip-icon-button'
+import { useElapsedSeconds } from '@/components/chat/activity-timer'
+import { ActivityTimerText } from '@/components/chat/activity-timer-text'
+import { DisclosureRow } from '@/components/chat/disclosure-row'
+import { GeneratedImageProvider, useGeneratedImageContext } from '@/components/chat/generated-image-context'
+import { ImageGenerationPlaceholder } from '@/components/chat/image-generation-placeholder'
+import { Intro, type IntroProps } from '@/components/chat/intro'
+import { PreviewAttachment } from '@/components/chat/preview-attachment'
 import { CopyButton } from '@/components/ui/copy-button'
 import {
   DropdownMenu,
@@ -354,6 +355,7 @@ const AssistantMessage: FC<{ onBranchInNewChat?: (messageId: string) => void }>
   const messageId = useAuiState(s => s.message.id)
   const content = useAuiState(s => s.message.content)
   const messageText = messageContentText(content)
+  const hoistedTodos = useMemo(() => todosFromMessageContent(content), [content])
 
   const previewTargets = useMemo(() => {
     if (!messageText || !/(https?:\/\/|file:\/\/)/i.test(messageText)) {
@@ -379,6 +381,7 @@ const AssistantMessage: FC<{ onBranchInNewChat?: (messageId: string) => void }>
         className="wrap-anywhere min-w-0 max-w-full overflow-hidden text-pretty text-base leading-(--dt-line-height) text-foreground"
         data-slot="aui_assistant-message-content"
       >
+        {hoistedTodos.length > 0 && <HoistedTodoPanel todos={hoistedTodos} />}
         <MessagePrimitive.Parts
           components={{
             Text: MarkdownText,
@@ -458,13 +461,12 @@ const ImageGenerateTool: FC<ToolCallMessagePartProps> = ({ result }) => {
 }
 
 const ChainToolFallback: FC<ToolCallMessagePartProps> = props => {
-  if (props.toolName === 'image_generate') {
-    return <ImageGenerateTool {...props} />
-  }
+  // todo parts are hoisted to a dedicated panel above the message content.
+  if (props.toolName === 'todo') {return null}
 
-  if (props.toolName === 'clarify') {
-    return <ClarifyTool {...props} />
-  }
+  if (props.toolName === 'image_generate') {return <ImageGenerateTool {...props} />}
+
+  if (props.toolName === 'clarify') {return <ClarifyTool {...props} />}
 
   return <ToolFallback {...props} />
 }
@@ -472,9 +474,10 @@ const ChainToolFallback: FC<ToolCallMessagePartProps> = props => {
 const ThinkingDisclosure: FC<{
   children: ReactNode
   pending?: boolean
-}> = ({ children, pending = false }) => {
+  timerKey?: string
+}> = ({ children, pending = false, timerKey }) => {
   const [open, setOpen] = useState(false)
-  const elapsed = useElapsedSeconds(pending)
+  const elapsed = useElapsedSeconds(pending, timerKey)
 
   return (
     <div className="text-sm text-muted-foreground" data-slot="aui_thinking-disclosure">
@@ -503,9 +506,10 @@ const ThinkingDisclosure: FC<{
 }
 
 const ReasoningAccordionGroup: FC<{ children?: ReactNode; endIndex: number; startIndex: number }> = ({ children }) => {
-  const pending = useAuiState(s => s.message.status?.type === 'running')
+  const pending = useAuiState(s => s.thread.isRunning && s.message.status?.type === 'running')
+  const messageId = useAuiState(s => s.message.id)
 
-  return <ThinkingDisclosure pending={pending}>{children}</ThinkingDisclosure>
+  return <ThinkingDisclosure pending={pending} timerKey={`reasoning:${messageId}`}>{children}</ThinkingDisclosure>
 }
 
 const ReasoningTextPart: FC<{ text: string; status?: { type: string } }> = ({ text, status }) => {
@@ -654,13 +658,13 @@ const AssistantFooter: FC<MessageActionProps> = props => (
       className="inline-flex h-6 items-center gap-1 text-xs text-muted-foreground"
       hideWhenSingleBranch
     >
-      <BranchPickerPrimitive.Previous className={branchButtonClass}>
+      <BranchPickerPrimitive.Previous className="grid size-6 place-items-center rounded-md text-muted-foreground transition-colors hover:bg-accent hover:text-foreground disabled:opacity-35">
         <ChevronLeftIcon className="size-3.5" />
       </BranchPickerPrimitive.Previous>
       <span className="tabular-nums">
         <BranchPickerPrimitive.Number /> / <BranchPickerPrimitive.Count />
       </span>
-      <BranchPickerPrimitive.Next className={branchButtonClass}>
+      <BranchPickerPrimitive.Next className="grid size-6 place-items-center rounded-md text-muted-foreground transition-colors hover:bg-accent hover:text-foreground disabled:opacity-35">
         <ChevronRightIcon className="size-3.5" />
       </BranchPickerPrimitive.Next>
     </BranchPickerPrimitive.Root>
@@ -668,9 +672,6 @@ const AssistantFooter: FC<MessageActionProps> = props => (
   </div>
 )
 
-const branchButtonClass =
-  'grid size-6 place-items-center rounded-md text-muted-foreground transition-colors hover:bg-accent hover:text-foreground disabled:opacity-35'
-
 const EMPTY_ATTACHMENT_REFS: string[] = []
 
 function messageAttachmentRefs(value: unknown): string[] {
diff --git a/apps/desktop/src/components/assistant-ui/todo-tool.tsx b/apps/desktop/src/components/assistant-ui/todo-tool.tsx
new file mode 100644
index 0000000000..6ec415ca1f
--- /dev/null
+++ b/apps/desktop/src/components/assistant-ui/todo-tool.tsx
@@ -0,0 +1,94 @@
+import { type FC } from 'react'
+
+import { Checkbox } from '@/components/ui/checkbox'
+import { Loader2Icon } from '@/lib/icons'
+import { parseTodos, type TodoItem, type TodoStatus } from '@/lib/todos'
+import { cn } from '@/lib/utils'
+
+export function todosFromMessageContent(content: unknown): TodoItem[] {
+  if (!Array.isArray(content)) {return []}
+
+  let latest: null | TodoItem[] = null
+
+  for (const part of content) {
+    if (!part || typeof part !== 'object') {continue}
+    const row = part as Record<string, unknown>
+
+    if (row.type !== 'tool-call' || row.toolName !== 'todo') {continue}
+    const parsed = parseTodos(row.result) ?? parseTodos(row.args)
+
+    if (parsed !== null) {latest = parsed}
+  }
+
+  return latest ?? []
+}
+
+const headerLabel = (todos: readonly TodoItem[]): string =>
+  todos.find(t => t.status === 'in_progress')?.content
+  ?? todos.find(t => t.status === 'pending')?.content
+  ?? todos.at(-1)?.content
+  ?? 'Tasks'
+
+const Checkmark: FC<{ status: TodoStatus; label: string }> = ({ status, label }) => {
+  if (status === 'in_progress') {
+    return (
+      <span
+        aria-label={`In progress: ${label}`}
+        className="grid size-[1.1rem] shrink-0 place-items-center rounded-full border border-ring/65 bg-[color-mix(in_srgb,var(--dt-ring)_14%,transparent)]"
+      >
+        <Loader2Icon className="size-3 animate-spin text-ring" />
+      </span>
+    )
+  }
+
+  const checked = status === 'completed'
+
+  return (
+    <Checkbox
+      aria-label={label}
+      checked={checked}
+      className={cn(
+        'size-[1.1rem] shrink-0 rounded-full border-border/80 pointer-events-none disabled:cursor-default disabled:opacity-100',
+        checked && 'data-[state=checked]:border-primary data-[state=checked]:bg-primary data-[state=checked]:text-primary-foreground [&_[data-slot=checkbox-indicator]_svg]:size-3',
+        status === 'cancelled' && 'border-muted-foreground/40'
+      )}
+      disabled
+    />
+  )
+}
+
+export const HoistedTodoPanel: FC<{ todos: TodoItem[] }> = ({ todos }) => {
+  if (!todos.length) {return null}
+  const label = headerLabel(todos)
+
+  return (
+    <section
+      className="mt-1 mb-3 inline-block w-fit max-w-full overflow-hidden rounded-2xl border border-border/70 bg-card align-top shadow-[0_1px_2px_0_hsl(var(--foreground)/0.04),0_1px_4px_-1px_hsl(var(--foreground)/0.06)]"
+      data-slot="aui_todo-hoisted"
+    >
+      <header className="px-3 pt-3 pb-2">
+        <span className="block max-w-full truncate text-[0.85rem] font-semibold leading-tight tracking-tight text-foreground" title={label}>
+          {label}
+        </span>
+      </header>
+      <ul className="grid min-w-0 gap-0.5 px-3 pb-3">
+        {todos.map(todo => (
+          <li
+            // Active row at full presence; everything else fades. Opacity on
+            // the row so the checkbox glyph dims with the text.
+            className={cn(
+              'flex min-w-0 items-center gap-3 py-1.5 transition-opacity',
+              todo.status === 'in_progress' ? 'opacity-100' : 'opacity-45'
+            )}
+            key={todo.id}
+          >
+            <Checkmark label={todo.content} status={todo.status} />
+            <span className="min-w-0 wrap-anywhere text-[0.8rem] leading-[1.2rem] text-foreground">
+              {todo.content}
+            </span>
+          </li>
+        ))}
+      </ul>
+    </section>
+  )
+}
diff --git a/apps/desktop/src/components/assistant-ui/tool-fallback.tsx b/apps/desktop/src/components/assistant-ui/tool-fallback.tsx
index 40f2d7a9e7..188dc62a94 100644
--- a/apps/desktop/src/components/assistant-ui/tool-fallback.tsx
+++ b/apps/desktop/src/components/assistant-ui/tool-fallback.tsx
@@ -4,12 +4,12 @@ import { type ToolCallMessagePartProps, useAuiState } from '@assistant-ui/react'
 import { useStore } from '@nanostores/react'
 import { type ReactNode, useEffect, useMemo, useRef } from 'react'
 
-import { useElapsedSeconds } from '@/components/assistant-ui/activity-timer'
-import { ActivityTimerText } from '@/components/assistant-ui/activity-timer-text'
-import { CompactMarkdown } from '@/components/assistant-ui/compact-markdown'
-import { DisclosureRow } from '@/components/assistant-ui/disclosure-row'
-import { PreviewAttachment } from '@/components/assistant-ui/preview-attachment'
-import { ZoomableImage } from '@/components/assistant-ui/zoomable-image'
+import { useElapsedSeconds } from '@/components/chat/activity-timer'
+import { ActivityTimerText } from '@/components/chat/activity-timer-text'
+import { CompactMarkdown } from '@/components/chat/compact-markdown'
+import { DisclosureRow } from '@/components/chat/disclosure-row'
+import { PreviewAttachment } from '@/components/chat/preview-attachment'
+import { ZoomableImage } from '@/components/chat/zoomable-image'
 import { CopyButton } from '@/components/ui/copy-button'
 import { FadeText } from '@/components/ui/fade-text'
 import { normalizeExternalUrl, PrettyLink, LinkifiedText as SharedLinkifiedText, urlSlugTitleLabel } from '@/lib/external-link'
@@ -26,12 +26,11 @@ import {
   Wrench
 } from '@/lib/icons'
 import type { LucideIcon } from '@/lib/icons'
+import { extractToolErrorMessage, formatToolResultSummary } from '@/lib/tool-result-summary'
 import { cn } from '@/lib/utils'
 import { $toolInlineDiffs } from '@/store/tool-diffs'
 import { $toolDisclosureStates, $toolViewMode, setToolDisclosureOpen } from '@/store/tool-view'
 
-const TOOL_DETAIL_INDENT_CLASS = 'w-full pl-(--message-text-indent) pr-2'
-
 type ToolTone = 'agent' | 'browser' | 'default' | 'file' | 'image' | 'terminal' | 'web'
 type ToolStatus = 'error' | 'running' | 'success' | 'warning'
 
@@ -386,52 +385,6 @@ function firstStringField(record: Record<string, unknown>, keys: readonly string
   return ''
 }
 
-function formatScalar(value: unknown): string {
-  if (typeof value === 'string') {
-    return value.trim()
-  }
-
-  if (typeof value === 'number' || typeof value === 'boolean') {
-    return String(value)
-  }
-
-  return ''
-}
-
-function summarizeRecord(record: Record<string, unknown>): string {
-  const title = firstStringField(record, ['title', 'name', 'path', 'file', 'filepath', 'url', 'href', 'link'])
-  const subtitle = firstStringField(record, ['url', 'href', 'link', 'status', 'category'])
-  const body = firstStringField(record, ['snippet', 'description', 'summary', 'message', 'preview', 'text', 'content'])
-
-  if (title || subtitle || body) {
-    return cleanVisibleText([title, subtitle !== title ? subtitle : '', body].filter(Boolean).join('\n'))
-  }
-
-  return Object.entries(record)
-    .map(([key, value]) => {
-      const scalar = formatScalar(value)
-
-      return scalar ? `${titleForTool(key)}: ${compactPreview(cleanVisibleText(scalar), 96)}` : ''
-    })
-    .filter(Boolean)
-    .slice(0, 4)
-    .join('\n')
-}
-
-function summarizeList(items: unknown[], max = 5): string {
-  return items
-    .map(item => {
-      if (isRecord(item) || (typeof item === 'string' && item.trim().startsWith('{'))) {
-        return summarizeRecord(parseMaybeObject(item))
-      }
-
-      return compactPreview(item, 140)
-    })
-    .filter(Boolean)
-    .slice(0, max)
-    .join('\n\n')
-}
-
 function collectResultItems(value: unknown): unknown[] {
   if (Array.isArray(value)) {
     return value
@@ -460,46 +413,6 @@ function collectResultItems(value: unknown): unknown[] {
   return payload === record ? [] : collectResultItems(payload)
 }
 
-function friendlyJsonSummary(value: unknown, depth = 0): string {
-  if (depth > 2) {
-    return ''
-  }
-
-  if (Array.isArray(value)) {
-    return summarizeList(value)
-  }
-
-  const record = parseMaybeObject(value)
-
-  if (!Object.keys(record).length) {
-    return ''
-  }
-
-  const direct = firstStringField(record, ['message', 'summary', 'preview', 'content', 'text', 'stdout', 'stderr', 'error'])
-
-  if (direct) {
-    return cleanVisibleText(direct)
-  }
-
-  const items = collectResultItems(record)
-
-  if (items.length) {
-    return summarizeList(items)
-  }
-
-  const payload = unwrapToolPayload(record)
-
-  if (payload !== value && payload !== record) {
-    const payloadSummary = friendlyJsonSummary(payload, depth + 1)
-
-    if (payloadSummary) {
-      return payloadSummary
-    }
-  }
-
-  return ''
-}
-
 function extractSearchResults(result: unknown, limit = 6): SearchResultRow[] {
   const list = collectResultItems(result)
 
@@ -518,16 +431,26 @@ function extractSearchResults(result: unknown, limit = 6): SearchResultRow[] {
 }
 
 function toolErrorText(part: ToolPart, result: Record<string, unknown>): string {
+  const extractedError = extractToolErrorMessage(part.result)
+
   if (part.isError) {
-    return 'Tool returned an error.'
+    return extractedError || (typeof part.result === 'string' && part.result.trim()) || 'Tool returned an error.'
   }
 
   if (typeof result.error === 'string' && result.error.trim()) {
     return result.error.trim()
   }
 
-  if (result.success === false) {
-    return firstStringField(result, ['message', 'reason']) || 'Tool returned success=false.'
+  if (extractedError) {
+    return extractedError
+  }
+
+  if (result.success === false || result.ok === false) {
+    return firstStringField(result, ['message', 'reason', 'detail']) || 'Tool returned success=false.'
+  }
+
+  if (typeof result.status === 'string' && /\b(error|failed|failure)\b/i.test(result.status)) {
+    return firstStringField(result, ['message', 'reason', 'detail']) || `Tool returned status "${result.status}".`
   }
 
   const exit = numberValue(result.exit_code)
@@ -630,6 +553,32 @@ function inlineDiffFromResult(result: unknown): string {
   return typeof value === 'string' ? stripInlineDiffChrome(value) : ''
 }
 
+function minimalValueSummary(value: unknown): string {
+  if (value == null) {
+    return ''
+  }
+
+  if (typeof value === 'string') {
+    return value
+  }
+
+  if (typeof value === 'number' || typeof value === 'boolean') {
+    return String(value)
+  }
+
+  if (Array.isArray(value)) {
+    return value.length ? `Returned ${value.length} items.` : 'No items returned.'
+  }
+
+  if (isRecord(value)) {
+    const count = Object.keys(value).length
+
+    return count ? `Returned object with ${count} fields.` : 'Returned an empty object.'
+  }
+
+  return String(value)
+}
+
 function fallbackDetailText(args: unknown, result: unknown): string {
   const argContext = contextValue(args)
   const resultContext = contextValue(result)
@@ -643,10 +592,10 @@ function fallbackDetailText(args: unknown, result: unknown): string {
   }
 
   if (result !== undefined) {
-    return friendlyJsonSummary(result) || prettyJson(result)
+    return formatToolResultSummary(result) || minimalValueSummary(result)
   }
 
-  return friendlyJsonSummary(args) || prettyJson(args)
+  return formatToolResultSummary(args) || minimalValueSummary(args)
 }
 
 function toolSubtitle(
@@ -743,7 +692,7 @@ function toolSubtitle(
   }
 
   return (
-    compactPreview(friendlyJsonSummary(part.result), 120) ||
+    compactPreview(formatToolResultSummary(part.result), 120) ||
     compactPreview(resultRecord, 120) ||
     compactPreview(argsRecord, 120) ||
     fallbackDetailText(argsRecord, resultRecord)
@@ -1011,15 +960,14 @@ function isToolPart(part: unknown): part is ToolPart {
 }
 
 function groupToolParts(content: unknown): ToolPart[][] {
-  if (!Array.isArray(content)) {
-    return []
-  }
+  if (!Array.isArray(content)) {return []}
 
   const groups: ToolPart[][] = []
   let current: ToolPart[] = []
 
   for (const part of content) {
-    if (isToolPart(part)) {
+    // todo parts render in their own hoisted panel; skip from grouped tools.
+    if (isToolPart(part) && part.toolName !== 'todo') {
       current.push(part)
 
       continue
@@ -1031,9 +979,7 @@ function groupToolParts(content: unknown): ToolPart[][] {
     }
   }
 
-  if (current.length) {
-    groups.push(current)
-  }
+  if (current.length) {groups.push(current)}
 
   return groups
 }
@@ -1134,17 +1080,25 @@ interface ToolEntryProps {
 }
 
 function ToolEntry({ embedded = false, part }: ToolEntryProps) {
-  const isPending = part.result === undefined
-  const elapsed = useElapsedSeconds(isPending)
+  const messageRunning = useAuiState(state => state.thread.isRunning && state.message.status?.type === 'running')
   const toolViewMode = useStore($toolViewMode)
   const disclosureStates = useStore($toolDisclosureStates)
   const disclosureId = toolPartDisclosureId(part)
+  const isPending = messageRunning && part.result === undefined
+  const elapsed = useElapsedSeconds(isPending, `tool:${disclosureId}`)
   const open = disclosureStates[disclosureId] ?? false
   const preview = compactPreview(part.args) || compactPreview(part.result)
   const liveDiffs = useStore($toolInlineDiffs)
   const sideDiff = part.toolCallId ? liveDiffs[part.toolCallId] || '' : ''
   const inlineDiff = stripInlineDiffChrome(sideDiff) || inlineDiffFromResult(part.result)
-  const view = useMemo(() => buildToolView(part, inlineDiff), [inlineDiff, part])
+
+  // Stale parts (no result, but message stopped running) get a synthetic
+  // empty result so buildToolView treats them as completed-no-output.
+  const view = useMemo(() => {
+    const p = !isPending && part.result === undefined ? { ...part, result: {} } : part
+
+    return buildToolView(p, inlineDiff)
+  }, [inlineDiff, isPending, part])
 
   const detailSections = useMemo(() => {
     if (!view.detail) {
@@ -1261,7 +1215,7 @@ function ToolEntry({ embedded = false, part }: ToolEntryProps) {
           ))}
       </DisclosureRow>
       {open && (
-        <div className={cn(TOOL_DETAIL_INDENT_CLASS, 'mt-2 grid min-w-0 max-w-full gap-2 overflow-hidden pb-2')}>
+        <div className={cn('w-full pl-(--message-text-indent) pr-2', 'mt-2 grid min-w-0 max-w-full gap-2 overflow-hidden pb-2')}>
           {!embedded && view.previewTarget && isPreviewableTarget(view.previewTarget) && (
             <PreviewAttachment source="tool-result" target={view.previewTarget} />
           )}
@@ -1359,7 +1313,8 @@ function groupPreviewTargets(parts: ToolPart[]): string[] {
 }
 
 function ToolGroup({ parts }: { parts: ToolPart[] }) {
-  const isRunning = parts.some(part => part.result === undefined)
+  const messageRunning = useAuiState(state => state.thread.isRunning && state.message.status?.type === 'running')
+  const isRunning = messageRunning && parts.some(part => part.result === undefined)
   const disclosureStates = useStore($toolDisclosureStates)
   const disclosureId = toolGroupDisclosureId(parts)
   const open = disclosureStates[disclosureId] ?? isRunning
@@ -1374,6 +1329,7 @@ function ToolGroup({ parts }: { parts: ToolPart[] }) {
   }, [disclosureId, isRunning])
 
   const status = groupStatus(parts)
+  const displayStatus = !isRunning && status === 'running' ? 'warning' : status
 
   const failedStepCount = useMemo(
     () => parts.filter(part => toolStatus(part, parseMaybeObject(part.result)) === 'error').length,
@@ -1395,9 +1351,9 @@ function ToolGroup({ parts }: { parts: ToolPart[] }) {
   }, [parts])
 
   const statusSummary =
-    status === 'running' || failedStepCount === 0
+    displayStatus === 'running' || failedStepCount === 0
       ? ''
-      : status === 'warning'
+      : displayStatus === 'warning'
         ? failedStepCount === 1
           ? 'Recovered after 1 failed step'
           : `Recovered after ${failedStepCount} failed steps`
@@ -1430,7 +1386,7 @@ function ToolGroup({ parts }: { parts: ToolPart[] }) {
       .join('\n\n')
   }, [parts])
 
-  const showGroupStatusGlyph = status !== 'success'
+  const showGroupStatusGlyph = displayStatus !== 'success'
   const previewTargets = useMemo(() => groupPreviewTargets(parts), [parts])
 
   return (
@@ -1446,13 +1402,13 @@ function ToolGroup({ parts }: { parts: ToolPart[] }) {
       >
         <span className="flex min-w-0 items-baseline gap-1.5">
           {showGroupStatusGlyph && (
-            <span className="flex h-[1.1rem] shrink-0 items-center">{statusGlyph(status)}</span>
+            <span className="flex h-[1.1rem] shrink-0 items-center">{statusGlyph(displayStatus)}</span>
           )}
           <FadeText
             className={cn(
               'text-[0.78rem] font-medium leading-[1.1rem] text-foreground/85',
-              status === 'error' && 'text-destructive',
-              status === 'warning' && 'text-amber-700 dark:text-amber-300'
+              displayStatus === 'error' && 'text-destructive',
+              displayStatus === 'warning' && 'text-amber-700 dark:text-amber-300'
             )}
           >
             {groupTitle(parts)}
@@ -1472,7 +1428,7 @@ function ToolGroup({ parts }: { parts: ToolPart[] }) {
           <FadeText
             className={cn(
               'text-[0.68rem] leading-[1.05rem]',
-              status === 'warning' ? 'text-amber-700/80 dark:text-amber-300/85' : 'text-destructive/85'
+              displayStatus === 'warning' ? 'text-amber-700/80 dark:text-amber-300/85' : 'text-destructive/85'
             )}
           >
             {statusSummary}
@@ -1480,14 +1436,14 @@ function ToolGroup({ parts }: { parts: ToolPart[] }) {
         )}
       </DisclosureRow>
       {previewTargets.length > 0 && (
-        <div className={cn(TOOL_DETAIL_INDENT_CLASS, 'mt-2 grid min-w-0 max-w-full gap-2 overflow-hidden')}>
+        <div className={cn('w-full pl-(--message-text-indent) pr-2', 'mt-2 grid min-w-0 max-w-full gap-2 overflow-hidden')}>
           {previewTargets.map(target => (
             <PreviewAttachment key={target} source="tool-result" target={target} />
           ))}
         </div>
       )}
       {open && (
-        <div className={cn(TOOL_DETAIL_INDENT_CLASS, 'mt-0.5 min-w-0 max-w-full overflow-hidden')}>
+        <div className={cn('w-full pl-(--message-text-indent) pr-2', 'mt-0.5 min-w-0 max-w-full overflow-hidden')}>
           {parts.map(part => (
             <ToolEntry embedded key={part.toolCallId || `${part.toolName}-${JSON.stringify(part.args)}`} part={part} />
           ))}
diff --git a/apps/desktop/src/components/assistant-ui/tool-group.tsx b/apps/desktop/src/components/assistant-ui/tool-group.tsx
deleted file mode 100644
index e1d34000e0..0000000000
--- a/apps/desktop/src/components/assistant-ui/tool-group.tsx
+++ /dev/null
@@ -1,9 +0,0 @@
-'use client'
-
-import { type ReactNode } from 'react'
-
-export const ToolGroupRoot = ({ children }: { children: ReactNode }) => (
-  <div className="my-2 flex flex-col gap-1">{children}</div>
-)
-export const ToolGroupTrigger = (_props: { count?: number; active?: boolean }) => null
-export const ToolGroupContent = ({ children }: { children: ReactNode }) => <div>{children}</div>
diff --git a/apps/desktop/src/components/assistant-ui/activity-timer-text.tsx b/apps/desktop/src/components/chat/activity-timer-text.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/activity-timer-text.tsx
rename to apps/desktop/src/components/chat/activity-timer-text.tsx
diff --git a/apps/desktop/src/components/chat/activity-timer.test.tsx b/apps/desktop/src/components/chat/activity-timer.test.tsx
new file mode 100644
index 0000000000..acc70a99ed
--- /dev/null
+++ b/apps/desktop/src/components/chat/activity-timer.test.tsx
@@ -0,0 +1,43 @@
+import { act, render, screen } from '@testing-library/react'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { __resetElapsedTimerRegistryForTests, useElapsedSeconds } from './activity-timer'
+
+function Probe({ active, timerKey }: { active: boolean; timerKey?: string }) {
+  const elapsed = useElapsedSeconds(active, timerKey)
+
+  return <span data-testid="elapsed">{elapsed}</span>
+}
+
+describe('useElapsedSeconds', () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+    vi.setSystemTime(new Date('2026-01-01T00:00:00.000Z'))
+    __resetElapsedTimerRegistryForTests()
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+    __resetElapsedTimerRegistryForTests()
+  })
+
+  it('keeps elapsed time stable across remounts for the same key', () => {
+    const first = render(<Probe active timerKey="tool:abc" />)
+
+    act(() => {
+      vi.advanceTimersByTime(5_000)
+    })
+
+    expect(screen.getByTestId('elapsed').textContent).toBe('5')
+
+    first.unmount()
+
+    act(() => {
+      vi.advanceTimersByTime(3_000)
+    })
+
+    render(<Probe active timerKey="tool:abc" />)
+
+    expect(screen.getByTestId('elapsed').textContent).toBe('8')
+  })
+})
diff --git a/apps/desktop/src/components/chat/activity-timer.ts b/apps/desktop/src/components/chat/activity-timer.ts
new file mode 100644
index 0000000000..704c9d4390
--- /dev/null
+++ b/apps/desktop/src/components/chat/activity-timer.ts
@@ -0,0 +1,52 @@
+import { useEffect, useRef, useState } from 'react'
+
+// Module-level registry so timers survive component unmount/remount (e.g.
+// when a tool row scrolls out and back). Keyed by caller-supplied timerKey;
+// anonymous timers (no key) start fresh each mount.
+const startedAtByKey = new Map<string, number>()
+
+function startedAt(key?: string): number {
+  if (!key) {return Date.now()}
+  const existing = startedAtByKey.get(key)
+
+  if (existing !== undefined) {return existing}
+  const now = Date.now()
+  startedAtByKey.set(key, now)
+
+  return now
+}
+
+export function formatElapsed(seconds: number): string {
+  if (seconds < 60) {return `${seconds}s`}
+
+  return `${Math.floor(seconds / 60)}:${String(seconds % 60).padStart(2, '0')}`
+}
+
+export function useElapsedSeconds(active = true, timerKey?: string): number {
+  const start = useRef(startedAt(timerKey))
+  const lastKey = useRef(timerKey)
+  const [elapsed, setElapsed] = useState(() => Math.max(0, Math.floor((Date.now() - start.current) / 1000)))
+
+  if (lastKey.current !== timerKey) {
+    start.current = startedAt(timerKey)
+    lastKey.current = timerKey
+  }
+
+  useEffect(() => {
+    if (!active) {return}
+
+    if (timerKey) {start.current = startedAt(timerKey)}
+
+    const tick = () => setElapsed(Math.max(0, Math.floor((Date.now() - start.current) / 1000)))
+    tick()
+    const id = window.setInterval(tick, 1000)
+
+    return () => window.clearInterval(id)
+  }, [active, timerKey])
+
+  return elapsed
+}
+
+export function __resetElapsedTimerRegistryForTests() {
+  startedAtByKey.clear()
+}
diff --git a/apps/desktop/src/components/assistant-ui/compact-markdown.tsx b/apps/desktop/src/components/chat/compact-markdown.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/compact-markdown.tsx
rename to apps/desktop/src/components/chat/compact-markdown.tsx
diff --git a/apps/desktop/src/components/assistant-ui/disclosure-row.tsx b/apps/desktop/src/components/chat/disclosure-row.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/disclosure-row.tsx
rename to apps/desktop/src/components/chat/disclosure-row.tsx
diff --git a/apps/desktop/src/components/assistant-ui/generated-image-context.tsx b/apps/desktop/src/components/chat/generated-image-context.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/generated-image-context.tsx
rename to apps/desktop/src/components/chat/generated-image-context.tsx
diff --git a/apps/desktop/src/components/assistant-ui/image-generation-placeholder.tsx b/apps/desktop/src/components/chat/image-generation-placeholder.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/image-generation-placeholder.tsx
rename to apps/desktop/src/components/chat/image-generation-placeholder.tsx
diff --git a/apps/desktop/src/components/assistant-ui/intro-copy.jsonl b/apps/desktop/src/components/chat/intro-copy.jsonl
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/intro-copy.jsonl
rename to apps/desktop/src/components/chat/intro-copy.jsonl
diff --git a/apps/desktop/src/components/assistant-ui/intro.tsx b/apps/desktop/src/components/chat/intro.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/intro.tsx
rename to apps/desktop/src/components/chat/intro.tsx
diff --git a/apps/desktop/src/components/assistant-ui/preview-attachment.tsx b/apps/desktop/src/components/chat/preview-attachment.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/preview-attachment.tsx
rename to apps/desktop/src/components/chat/preview-attachment.tsx
diff --git a/apps/desktop/src/components/assistant-ui/shiki-highlighter.tsx b/apps/desktop/src/components/chat/shiki-highlighter.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/shiki-highlighter.tsx
rename to apps/desktop/src/components/chat/shiki-highlighter.tsx
diff --git a/apps/desktop/src/components/assistant-ui/zoomable-image.tsx b/apps/desktop/src/components/chat/zoomable-image.tsx
similarity index 100%
rename from apps/desktop/src/components/assistant-ui/zoomable-image.tsx
rename to apps/desktop/src/components/chat/zoomable-image.tsx
diff --git a/apps/desktop/src/components/model-picker.tsx b/apps/desktop/src/components/model-picker.tsx
index f82922a134..a47f7cf992 100644
--- a/apps/desktop/src/components/model-picker.tsx
+++ b/apps/desktop/src/components/model-picker.tsx
@@ -14,8 +14,6 @@ import { Command, CommandEmpty, CommandGroup, CommandInput, CommandItem, Command
 import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from './ui/dialog'
 import { Skeleton } from './ui/skeleton'
 
-const pickerPanelClass = 'max-h-[85vh] max-w-2xl gap-0 overflow-hidden p-0'
-
 interface ModelPickerDialogProps {
   open: boolean
   onOpenChange: (open: boolean) => void
@@ -73,7 +71,7 @@ export function ModelPickerDialog({
 
   return (
     <Dialog onOpenChange={onOpenChange} open={open}>
-      <DialogContent className={pickerPanelClass}>
+      <DialogContent className="max-h-[85vh] max-w-2xl gap-0 overflow-hidden p-0">
         <DialogHeader className="border-b border-border px-4 py-3">
           <DialogTitle>Switch model</DialogTitle>
           <DialogDescription className="font-mono text-xs leading-relaxed">
diff --git a/apps/desktop/src/lib/chat-messages.test.ts b/apps/desktop/src/lib/chat-messages.test.ts
index 5fbbb0a03f..beaf18c764 100644
--- a/apps/desktop/src/lib/chat-messages.test.ts
+++ b/apps/desktop/src/lib/chat-messages.test.ts
@@ -26,6 +26,46 @@ describe('toChatMessages', () => {
     expect(chatMessageText(messages[0])).toBe('Planning.Done.')
   })
 
+  it('keeps assistant tool-call iterations in one loaded assistant bubble', () => {
+    const messages = toChatMessages([
+      { role: 'user', content: 'check this repo', timestamp: 1 },
+      {
+        role: 'assistant',
+        content: "Let me also check if there's a top-level lint workflow.",
+        timestamp: 2,
+        tool_calls: [{ id: 'tc-1', function: { name: 'search_files', arguments: '{"path":".github"}' } }]
+      },
+      {
+        role: 'tool',
+        tool_call_id: 'tc-1',
+        tool_name: 'search_files',
+        content: '{"error":"Path not found: /repo/.github"}',
+        timestamp: 3
+      },
+      {
+        role: 'assistant',
+        content: 'No CI in this repo. Build is enough.',
+        timestamp: 4,
+        tool_calls: [{ id: 'tc-2', function: { name: 'terminal', arguments: '{"command":"git status --short"}' } }]
+      },
+      {
+        role: 'tool',
+        tool_call_id: 'tc-2',
+        tool_name: 'terminal',
+        content: '{"output":"M src/ui/components/image-distortion.tsx\\n","exit_code":0}',
+        timestamp: 5
+      },
+      { role: 'assistant', content: 'Now let me check git status and commit.', timestamp: 6 }
+    ])
+
+    const assistantMessages = messages.filter(message => message.role === 'assistant')
+
+    expect(assistantMessages).toHaveLength(1)
+    expect(assistantMessages[0].parts.filter(part => part.type === 'tool-call')).toHaveLength(2)
+    expect(chatMessageText(assistantMessages[0])).toContain("Let me also check if there's a top-level lint workflow.")
+    expect(chatMessageText(assistantMessages[0])).toContain('Now let me check git status and commit.')
+  })
+
   it('hides attached context payloads from user message display', () => {
     const [message] = toChatMessages([
       {
@@ -120,4 +160,68 @@ describe('upsertToolPart', () => {
       inline_diff: '--- a/foo.ts\n+++ b/foo.ts\n@@\n-old\n+new'
     })
   })
+
+  it('keeps live todo rows stable across sparse progress payloads', () => {
+    const first = upsertToolPart(
+      [],
+      {
+        name: 'todo',
+        todos: [{ content: 'Boil water', id: 'boil', status: 'in_progress' }],
+        tool_id: 'todo-1'
+      },
+      'running'
+    )
+
+    const progressed = upsertToolPart(
+      first,
+      {
+        name: 'todo',
+        preview: 'updating plan',
+        tool_id: 'todo-1'
+      },
+      'running'
+    )
+
+    const [part] = progressed
+    const args = part && 'args' in part ? (part.args as Record<string, unknown>) : {}
+
+    expect(args.todos).toEqual([{ content: 'Boil water', id: 'boil', status: 'in_progress' }])
+  })
+
+  it('archives todo state on completion and accepts explicit empty clears', () => {
+    const started = upsertToolPart(
+      [],
+      {
+        name: 'todo',
+        todos: [{ content: 'Boil water', id: 'boil', status: 'in_progress' }],
+        tool_id: 'todo-1'
+      },
+      'running'
+    )
+
+    const completed = upsertToolPart(
+      started,
+      {
+        name: 'todo',
+        tool_id: 'todo-1'
+      },
+      'complete'
+    )
+
+    const cleared = upsertToolPart(
+      completed,
+      {
+        name: 'todo',
+        todos: [],
+        tool_id: 'todo-1'
+      },
+      'complete'
+    )
+
+    const completedResult = completed[0] && 'result' in completed[0] ? (completed[0].result as Record<string, unknown>) : {}
+    const clearedResult = cleared[0] && 'result' in cleared[0] ? (cleared[0].result as Record<string, unknown>) : {}
+
+    expect(completedResult.todos).toEqual([{ content: 'Boil water', id: 'boil', status: 'in_progress' }])
+    expect(clearedResult.todos).toEqual([])
+  })
 })
diff --git a/apps/desktop/src/lib/chat-messages.ts b/apps/desktop/src/lib/chat-messages.ts
index 0c072db3ae..77b018a274 100644
--- a/apps/desktop/src/lib/chat-messages.ts
+++ b/apps/desktop/src/lib/chat-messages.ts
@@ -1,6 +1,7 @@
 import type { ThreadMessageLike } from '@assistant-ui/react'
 
 import { mediaDisplayLabel, mediaMarkdownHref } from '@/lib/media'
+import { parseTodos } from '@/lib/todos'
 import type { SessionMessage, UsageStats } from '@/types/hermes'
 
 export type ChatMessagePart = Exclude<ThreadMessageLike['content'], string>[number]
@@ -211,21 +212,42 @@ function toolId(payload: GatewayEventPayload | undefined): string {
   return payload?.tool_id || payload?.name || `tool-${Date.now()}`
 }
 
-function toolArgs(payload: GatewayEventPayload | undefined): Record<string, unknown> {
+// Carry todo state across sparse progress payloads: if this todo event lacks
+// a `todos` field, fall back to whatever we previously stored on the part.
+function carryTodos(payload: GatewayEventPayload | undefined, ...prev: unknown[]): { todos: unknown } | undefined {
+  if (payload && Object.hasOwn(payload, 'todos')) {
+    const next = parseTodos(payload.todos)
+
+    return next === null ? undefined : { todos: next }
+  }
+
+  if (payload?.name !== 'todo') {return undefined}
+
+  for (const p of prev) {
+    const carried = parseTodos(recordFromUnknown(p)?.todos)
+
+    if (carried !== null) {return { todos: carried }}
+  }
+
+  return undefined
+}
+
+function toolArgs(payload: GatewayEventPayload | undefined, prevArgs?: unknown): Record<string, unknown> {
   return {
     ...(payload?.context ? { context: payload.context } : {}),
-    ...(payload?.preview ? { preview: payload.preview } : {})
+    ...(payload?.preview ? { preview: payload.preview } : {}),
+    ...carryTodos(payload, prevArgs)
   }
 }
 
-function toolResult(payload: GatewayEventPayload | undefined): Record<string, unknown> {
+function toolResult(payload: GatewayEventPayload | undefined, prevResult?: unknown, prevArgs?: unknown): Record<string, unknown> {
   return {
     ...(payload?.inline_diff ? { inline_diff: payload.inline_diff } : {}),
     ...(payload?.summary ? { summary: payload.summary } : {}),
     ...(payload?.message ? { message: payload.message } : {}),
     ...(payload?.preview ? { preview: payload.preview } : {}),
     ...(payload?.duration_s !== undefined ? { duration_s: payload.duration_s } : {}),
-    ...(payload?.todos ? { todos: payload.todos } : {}),
+    ...carryTodos(payload, prevResult, prevArgs),
     ...(payload?.error ? { error: payload.error } : {})
   }
 }
@@ -243,24 +265,21 @@ export function upsertToolPart(
     part => part.type === 'tool-call' && ((part.toolCallId && part.toolCallId === id) || part.toolName === name)
   )
 
+  const prev = index >= 0 ? next[index] : null
+  const prevArgs = prev && 'args' in prev ? prev.args : undefined
+  const prevResult = prev && 'result' in prev ? prev.result : undefined
+  const args = toolArgs(payload, prevArgs)
+
   const base = {
     type: 'tool-call' as const,
     toolCallId: id,
     toolName: name,
-    args: toolArgs(payload) as never,
-    argsText: JSON.stringify(toolArgs(payload)),
-    ...(phase === 'complete'
-      ? {
-          result: toolResult(payload),
-          isError: Boolean(payload?.error)
-        }
-      : {})
+    args: args as never,
+    argsText: JSON.stringify(args),
+    ...(phase === 'complete' && { result: toolResult(payload, prevResult, prevArgs), isError: Boolean(payload?.error) })
   } satisfies ChatMessagePart
 
-  if (index === -1) {
-    return [...next, base]
-  }
-
+  if (index === -1) {return [...next, base]}
   next[index] = { ...next[index], ...base }
 
   return next
@@ -457,20 +476,48 @@ export function toChatMessages(messages: SessionMessage[]): ChatMessage[] {
   const result: ChatMessage[] = []
   let pendingToolParts: ChatMessagePart[] = []
   let pendingToolTimestamp: number | undefined
+  let activeAssistantIndex: null | number = null
+
+  const clearPendingTools = () => {
+    pendingToolParts = []
+    pendingToolTimestamp = undefined
+  }
+
+  const appendPartsToActiveAssistant = (parts: ChatMessagePart[], timestamp?: number): boolean => {
+    if (activeAssistantIndex === null) {
+      return false
+    }
+
+    const active = result[activeAssistantIndex]
+
+    if (!active || active.role !== 'assistant') {
+      activeAssistantIndex = null
+
+      return false
+    }
+
+    active.parts = [...active.parts, ...parts]
+    active.timestamp = timestamp ?? active.timestamp
+
+    return true
+  }
 
   const flushPendingTools = (index: number) => {
     if (!pendingToolParts.length) {
       return
     }
 
-    result.push({
-      id: `${pendingToolTimestamp || Date.now()}-${index}-tools`,
-      role: 'assistant',
-      parts: pendingToolParts,
-      timestamp: pendingToolTimestamp
-    })
-    pendingToolParts = []
-    pendingToolTimestamp = undefined
+    if (!appendPartsToActiveAssistant(pendingToolParts, pendingToolTimestamp)) {
+      result.push({
+        id: `${pendingToolTimestamp || Date.now()}-${index}-tools`,
+        role: 'assistant',
+        parts: pendingToolParts,
+        timestamp: pendingToolTimestamp
+      })
+      activeAssistantIndex = result.length - 1
+    }
+
+    clearPendingTools()
   }
 
   messages.forEach((message, index) => {
@@ -515,6 +562,11 @@ export function toChatMessages(messages: SessionMessage[]): ChatMessage[] {
     }
 
     if (!parts.length) {
+      if (message.role !== 'assistant') {
+        flushPendingTools(index)
+        activeAssistantIndex = null
+      }
+
       return
     }
 
@@ -528,22 +580,30 @@ export function toChatMessages(messages: SessionMessage[]): ChatMessage[] {
       return
     }
 
-    if (message.role === 'assistant' && pendingToolParts.length) {
-      const last = result.at(-1)
+    if (message.role === 'assistant') {
+      if (pendingToolParts.length) {
+        if (!appendPartsToActiveAssistant(pendingToolParts, message.timestamp ?? pendingToolTimestamp)) {
+          parts.unshift(...pendingToolParts)
+        }
 
-      if (last?.role === 'assistant') {
-        last.parts = [...last.parts, ...pendingToolParts, ...parts]
-        last.timestamp = message.timestamp ?? last.timestamp
-        pendingToolParts = []
-        pendingToolTimestamp = undefined
+        clearPendingTools()
+      }
+
+      const activeAssistant =
+        activeAssistantIndex !== null && result[activeAssistantIndex]?.role === 'assistant'
+          ? result[activeAssistantIndex]
+          : null
+
+      const currentHasToolCall = parts.some(part => part.type === 'tool-call')
+      const activeHasToolCall = Boolean(activeAssistant?.parts.some(part => part.type === 'tool-call'))
+
+      if (activeAssistant && (currentHasToolCall || activeHasToolCall)) {
+        activeAssistant.parts = [...activeAssistant.parts, ...parts]
+        activeAssistant.timestamp = message.timestamp ?? activeAssistant.timestamp
 
         return
       }
-
-      parts.unshift(...pendingToolParts)
-      pendingToolParts = []
-      pendingToolTimestamp = undefined
-    } else if (message.role !== 'assistant') {
+    } else {
       flushPendingTools(index)
     }
 
@@ -553,6 +613,8 @@ export function toChatMessages(messages: SessionMessage[]): ChatMessage[] {
       parts,
       timestamp: message.timestamp
     })
+
+    activeAssistantIndex = message.role === 'assistant' ? result.length - 1 : null
   })
   flushPendingTools(messages.length)
 
diff --git a/apps/desktop/src/lib/todos.test.ts b/apps/desktop/src/lib/todos.test.ts
new file mode 100644
index 0000000000..ebd296ab7a
--- /dev/null
+++ b/apps/desktop/src/lib/todos.test.ts
@@ -0,0 +1,35 @@
+import { describe, expect, it } from 'vitest'
+
+import { parseTodos } from './todos'
+
+describe('parseTodos', () => {
+  it('parses todo arrays with valid ids, content, and statuses', () => {
+    expect(
+      parseTodos([
+        { content: 'Gather ingredients', id: 'prep', status: 'completed' },
+        { content: 'Boil water', id: 'boil', status: 'in_progress' },
+        { content: 'Serve', id: 'serve', status: 'pending' }
+      ])
+    ).toEqual([
+      { content: 'Gather ingredients', id: 'prep', status: 'completed' },
+      { content: 'Boil water', id: 'boil', status: 'in_progress' },
+      { content: 'Serve', id: 'serve', status: 'pending' }
+    ])
+  })
+
+  it('parses nested todo payloads from wrapped objects and JSON strings', () => {
+    expect(parseTodos({ todos: [{ content: 'Plate', id: 'plate', status: 'pending' }] })).toEqual([
+      { content: 'Plate', id: 'plate', status: 'pending' }
+    ])
+
+    expect(parseTodos('{"todos":[{"id":"plate","content":"Plate","status":"pending"}]}')).toEqual([
+      { content: 'Plate', id: 'plate', status: 'pending' }
+    ])
+  })
+
+  it('returns null for non-todo payloads', () => {
+    expect(parseTodos(undefined)).toBeNull()
+    expect(parseTodos('not json')).toBeNull()
+    expect(parseTodos({ message: 'no todos here' })).toBeNull()
+  })
+})
diff --git a/apps/desktop/src/lib/todos.ts b/apps/desktop/src/lib/todos.ts
new file mode 100644
index 0000000000..cd328fc286
--- /dev/null
+++ b/apps/desktop/src/lib/todos.ts
@@ -0,0 +1,38 @@
+export type TodoStatus = 'pending' | 'in_progress' | 'completed' | 'cancelled'
+
+export interface TodoItem {
+  content: string
+  id: string
+  status: TodoStatus
+}
+
+const STATUSES: readonly TodoStatus[] = ['pending', 'in_progress', 'completed', 'cancelled']
+
+const isRecord = (v: unknown): v is Record<string, unknown> => Boolean(v && typeof v === 'object' && !Array.isArray(v))
+const isStatus = (v: unknown): v is TodoStatus => (STATUSES as readonly string[]).includes(v as string)
+
+function parseArray(value: unknown[]): TodoItem[] {
+  return value.flatMap(item => {
+    if (!isRecord(item) || !isStatus(item.status)) {return []}
+    const id = String(item.id ?? '').trim()
+    const content = String(item.content ?? '').trim()
+
+    return id && content ? [{ content, id, status: item.status }] : []
+  })
+}
+
+function parse(value: unknown, depth: number): null | TodoItem[] {
+  if (depth > 2) {return null}
+
+  if (Array.isArray(value)) {return parseArray(value)}
+
+  if (typeof value === 'string' && value.trim()) {
+    try { return parse(JSON.parse(value), depth + 1) } catch { return null }
+  }
+
+  if (isRecord(value) && Object.hasOwn(value, 'todos')) {return parse(value.todos, depth + 1)}
+
+  return null
+}
+
+export const parseTodos = (value: unknown): null | TodoItem[] => parse(value, 0)
diff --git a/apps/desktop/src/lib/tool-result-summary.test.ts b/apps/desktop/src/lib/tool-result-summary.test.ts
new file mode 100644
index 0000000000..4a0a841caf
--- /dev/null
+++ b/apps/desktop/src/lib/tool-result-summary.test.ts
@@ -0,0 +1,108 @@
+import { describe, expect, it } from 'vitest'
+
+import { extractToolErrorMessage, formatToolResultSummary } from './tool-result-summary'
+
+describe('formatToolResultSummary', () => {
+  it('unwraps wrapper payloads into structured key-value lines', () => {
+    const summary = formatToolResultSummary({
+      success: true,
+      result: {
+        data: {
+          path: '/tmp/demo.txt',
+          status: 'ok',
+          lines_written: 12,
+          checksum: 'abc123'
+        }
+      }
+    })
+
+    expect(summary).toContain('- Path: /tmp/demo.txt')
+    expect(summary).toContain('- Status: ok')
+    expect(summary).toContain('- Lines Written: 12')
+    expect(summary).not.toContain('"path"')
+  })
+
+  it('summarizes object arrays as readable list items', () => {
+    const summary = formatToolResultSummary([
+      { title: 'First result', snippet: 'alpha preview text' },
+      { title: 'Second result', status: 'cached' },
+      { title: 'Third result', summary: 'more details' },
+      { title: 'Fourth result', summary: 'line 4' },
+      { title: 'Fifth result', summary: 'line 5' },
+      { title: 'Sixth result', summary: 'line 6' },
+      { title: 'Seventh result', summary: 'line 7' }
+    ])
+
+    expect(summary).toContain('- First result - alpha preview text')
+    expect(summary).toContain('- Second result (cached)')
+    expect(summary).toContain('- … 1 more item')
+  })
+
+  it('truncates long field values for compact display', () => {
+    const summary = formatToolResultSummary({
+      message: 'ok',
+      details: `prefix ${'x'.repeat(500)}`
+    })
+
+    const detailsLine = summary
+      .split('\n')
+      .find(line => line.startsWith('- Details:'))
+
+    expect(detailsLine).toBeTruthy()
+    expect(detailsLine?.length).toBeLessThan(230)
+    expect(detailsLine).toContain('…')
+  })
+
+  it('formats stringified json payloads without raw dumps', () => {
+    const summary = formatToolResultSummary(
+      JSON.stringify({
+        data: {
+          title: 'Build report',
+          completed: true
+        }
+      })
+    )
+
+    expect(summary).toContain('- Title: Build report')
+    expect(summary).toContain('- Completed: true')
+  })
+})
+
+describe('extractToolErrorMessage', () => {
+  it('finds nested error messages through wrappers', () => {
+    const error = extractToolErrorMessage({
+      success: false,
+      result: {
+        output: {
+          error: {
+            message: 'Permission denied writing /tmp/demo.txt'
+          }
+        }
+      }
+    })
+
+    expect(error).toBe('Permission denied writing /tmp/demo.txt')
+  })
+
+  it('does not treat successful payload messages as errors', () => {
+    const error = extractToolErrorMessage({
+      success: true,
+      message: 'Completed successfully',
+      data: { count: 3 }
+    })
+
+    expect(error).toBe('')
+  })
+
+  it('ignores placeholder error fields in successful payloads', () => {
+    const error = extractToolErrorMessage({
+      success: true,
+      data: {
+        error: 'none',
+        status: 'ok'
+      }
+    })
+
+    expect(error).toBe('')
+  })
+})
diff --git a/apps/desktop/src/lib/tool-result-summary.ts b/apps/desktop/src/lib/tool-result-summary.ts
new file mode 100644
index 0000000000..912bebacea
--- /dev/null
+++ b/apps/desktop/src/lib/tool-result-summary.ts
@@ -0,0 +1,326 @@
+// Heuristic JSON → human summary for tool results. Default view; technical
+// mode still gets the raw JSON section.
+
+const WRAPPER_KEYS = ['data', 'result', 'output', 'response', 'payload'] as const
+const PRIORITY_KEYS = ['title', 'name', 'path', 'file', 'filepath', 'url', 'href', 'link', 'status', 'id', 'message', 'summary', 'description'] as const
+const ERROR_KEYS = ['error', 'errors', 'failure', 'exception'] as const
+const ERROR_MSG_KEYS = ['message', 'reason', 'detail', 'stderr'] as const
+const NON_ERROR_TEXT = new Set(['', '0', 'false', 'none', 'null', 'nil', 'ok', 'success', 'n/a', 'na'])
+
+type Json = Record<string, unknown>
+
+const isRecord = (v: unknown): v is Json => Boolean(v && typeof v === 'object' && !Array.isArray(v))
+
+function tryJson(value: string): unknown {
+  const t = value.trim()
+
+  if (!t) {return ''}
+
+  if (!/^[{[]|^"/.test(t)) {return value}
+
+  try { return JSON.parse(t) } catch { return value }
+}
+
+const norm = (v: unknown): unknown => (typeof v === 'string' ? tryJson(v) : v)
+
+const titleCase = (k: string) =>
+  k.split(/[_\-.]+/).filter(Boolean).map(p => `${p[0]?.toUpperCase() ?? ''}${p.slice(1)}`).join(' ')
+
+const pluralize = (n: number, noun: string) => `${n} ${noun}${n === 1 ? '' : 's'}`
+
+function clipInline(value: string, max = 180): string {
+  const c = value.replace(/\s+/g, ' ').trim()
+
+  return c.length > max ? `${c.slice(0, max - 1)}…` : c
+}
+
+function clipBlock(value: string, maxChars = 1800, maxLines = 18): string {
+  const t = value.trim()
+
+  if (!t) {return ''}
+  const lines = t.split('\n')
+  let text = lines.slice(0, maxLines).join('\n')
+  const clipped = lines.length > maxLines || text.length > maxChars
+
+  if (text.length > maxChars) {text = text.slice(0, maxChars - 1).trimEnd()}
+
+  return clipped && !text.endsWith('…') ? `${text}…` : text
+}
+
+function firstString(record: Json, keys: readonly string[]): string {
+  for (const k of keys) {
+    const v = record[k]
+
+    if (typeof v === 'string' && v.trim()) {return v.trim()}
+  }
+
+  return ''
+}
+
+function orderedKeys(keys: string[]): string[] {
+  const priority = PRIORITY_KEYS.filter(k => keys.includes(k))
+  const rest = keys.filter(k => !priority.includes(k as never))
+
+  return [...priority, ...rest]
+}
+
+const isWrapperKey = (k: string) => (WRAPPER_KEYS as readonly string[]).includes(k)
+const skipField = (k: string, v: unknown) => isWrapperKey(k) || ((k === 'success' || k === 'ok') && v === true)
+
+function summarizeScalar(v: unknown): string {
+  if (typeof v === 'string') {return clipInline(v)}
+
+  if (typeof v === 'number' || typeof v === 'boolean') {return String(v)}
+
+  return ''
+}
+
+function summarizeRecordInline(record: Json, depth: number): string {
+  if (depth > 3) {return pluralize(Object.keys(record).length, 'field')}
+
+  const title = firstString(record, ['title', 'name', 'path', 'file', 'filepath', 'url', 'href', 'link', 'id'])
+  const status = firstString(record, ['status', 'category', 'type'])
+  const message = firstString(record, ['snippet', 'summary', 'description', 'message'])
+
+  if (title && status) {return `${clipInline(title, 110)} (${clipInline(status, 54)})`}
+
+  if (title && message && title !== message) {return `${clipInline(title, 90)} - ${clipInline(message, 84)}`}
+
+  if (title) {return clipInline(title, 150)}
+
+  const pairs = orderedKeys(Object.keys(record))
+    .filter(k => !skipField(k, record[k]))
+    .map(k => {
+      const s = summarizeScalar(record[k])
+
+      return s ? `${titleCase(k)}: ${s}` : ''
+    })
+    .filter(Boolean)
+    .slice(0, 2)
+
+  return pairs.length ? pairs.join(' · ') : pluralize(Object.keys(record).length, 'field')
+}
+
+function summarizeListItem(item: unknown, depth: number): string {
+  const v = norm(item)
+
+  if (typeof v === 'string') {return clipInline(v)}
+
+  if (typeof v === 'number' || typeof v === 'boolean') {return String(v)}
+
+  if (v == null) {return ''}
+
+  if (Array.isArray(v)) {return pluralize(v.length, 'item')}
+
+  if (isRecord(v)) {return summarizeRecordInline(v, depth + 1)}
+
+  return clipInline(String(v))
+}
+
+function formatFieldValue(value: unknown, depth: number): string {
+  const v = norm(value)
+  const scalar = summarizeScalar(v)
+
+  if (scalar) {return scalar}
+
+  if (v == null) {return ''}
+
+  if (Array.isArray(v)) {
+    if (!v.length) {return '0 items'}
+    const scalars = v.map(summarizeScalar).filter(Boolean)
+
+    if (scalars.length === v.length && v.length <= 4) {return clipInline(scalars.join(', '))}
+    const first = summarizeListItem(v[0], depth + 1)
+
+    return first ? `${pluralize(v.length, 'item')} (${first})` : pluralize(v.length, 'item')
+  }
+
+  if (isRecord(v)) {return summarizeRecordInline(v, depth + 1)}
+
+  return clipInline(String(v))
+}
+
+function formatArraySummary(value: unknown[], depth: number): string {
+  if (!value.length) {return 'No items returned.'}
+
+  const max = 6
+  const lines = value.slice(0, max).map(item => summarizeListItem(item, depth + 1)).filter(Boolean).map(l => `- ${l}`)
+
+  if (!lines.length) {return `Returned ${pluralize(value.length, 'item')}.`}
+
+  if (value.length > max) {
+    const remaining = value.length - max
+    lines.push(`- … ${remaining} more ${remaining === 1 ? 'item' : 'items'}`)
+  }
+
+  return lines.join('\n')
+}
+
+function formatRecordSummary(record: Json, depth: number): string {
+  const keys = Object.keys(record)
+
+  if (!keys.length) {return 'Returned an empty object.'}
+
+  if (depth <= 2) {
+    const direct = firstString(record, ['message', 'summary', 'description', 'preview', 'text', 'content'])
+    const meaningful = keys.filter(k => !skipField(k, record[k]) && !isWrapperKey(k))
+
+    if (direct && meaningful.length <= 1) {return clipBlock(direct)}
+  }
+
+  const candidates = orderedKeys(keys).filter(k => !skipField(k, record[k]))
+  const max = 8
+  const lines: string[] = []
+
+  for (const k of candidates) {
+    const v = formatFieldValue(record[k], depth + 1)
+
+    if (!v) {continue}
+    lines.push(`- ${titleCase(k)}: ${v}`)
+
+    if (lines.length >= max) {break}
+  }
+
+  if (!lines.length) {return `Returned object with ${pluralize(keys.length, 'field')}.`}
+
+  if (candidates.length > lines.length) {
+    const remaining = candidates.length - lines.length
+    lines.push(`- … ${remaining} more ${remaining === 1 ? 'field' : 'fields'}`)
+  }
+
+  return lines.join('\n')
+}
+
+function formatSummaryValue(value: unknown, depth: number): string {
+  if (depth > 4) {return ''}
+  const v = norm(value)
+
+  if (typeof v === 'string') {return clipBlock(v)}
+
+  if (typeof v === 'number' || typeof v === 'boolean') {return String(v)}
+
+  if (v == null) {return ''}
+
+  if (Array.isArray(v)) {return formatArraySummary(v, depth + 1)}
+
+  if (isRecord(v)) {return formatRecordSummary(v, depth + 1)}
+
+  return clipInline(String(v))
+}
+
+function unwrapPayload(value: unknown): unknown {
+  let cur: unknown = norm(value)
+
+  for (let i = 0; i < 4; i += 1) {
+    if (!isRecord(cur)) {
+      return cur
+    }
+
+    const record = cur
+    const key = WRAPPER_KEYS.find(k => record[k] != null)
+
+    if (!key) {
+      return record
+    }
+
+    cur = norm(record[key])
+  }
+
+  return cur
+}
+
+function hasMeaningfulErrorValue(value: unknown): boolean {
+  const v = norm(value)
+
+  if (v == null) {return false}
+
+  if (typeof v === 'string') {return !NON_ERROR_TEXT.has(v.trim().toLowerCase())}
+
+  if (typeof v === 'boolean') {return v}
+
+  if (typeof v === 'number') {return v !== 0}
+
+  if (Array.isArray(v)) {return v.some(hasMeaningfulErrorValue)}
+
+  if (isRecord(v)) {return Object.keys(v).length > 0}
+
+  return true
+}
+
+function hasErrorSignal(record: Json): boolean {
+  const status = typeof record.status === 'string' ? record.status : ''
+
+  return (
+    record.success === false ||
+    record.ok === false ||
+    /\b(error|failed|failure|fatal|exception)\b/i.test(status) ||
+    ERROR_KEYS.some(k => hasMeaningfulErrorValue(record[k]))
+  )
+}
+
+function valueErrorText(value: unknown): string {
+  const v = norm(value)
+
+  if (typeof v === 'string') {return hasMeaningfulErrorValue(v) ? clipBlock(v, 700, 12) : ''}
+
+  if (Array.isArray(v)) {
+    return clipBlock(v.map(valueErrorText).filter(Boolean).slice(0, 3).join('; '), 700, 12)
+  }
+
+  if (isRecord(v)) {
+    const direct = firstString(v, ERROR_MSG_KEYS)
+
+    if (direct) {return clipBlock(direct, 700, 12)}
+  }
+
+  return ''
+}
+
+function findNestedError(value: unknown, depth: number, seen: Set<unknown>): string {
+  if (depth > 5) {return ''}
+  const v = norm(value)
+
+  if (!v || typeof v !== 'object' || seen.has(v)) {return ''}
+  seen.add(v)
+
+  if (Array.isArray(v)) {
+    for (const item of v) {
+      const nested = findNestedError(item, depth + 1, seen)
+
+      if (nested) {return nested}
+    }
+
+    return ''
+  }
+
+  const record = v as Json
+
+  for (const k of ERROR_KEYS) {
+    if (!hasMeaningfulErrorValue(record[k])) {continue}
+    const text = valueErrorText(record[k])
+
+    if (text) {return text}
+  }
+
+  if (hasErrorSignal(record)) {
+    const direct = firstString(record, ERROR_MSG_KEYS)
+
+    if (direct) {return clipBlock(direct, 700, 12)}
+  }
+
+  for (const k of [...ERROR_KEYS, ...WRAPPER_KEYS, 'details', 'meta']) {
+    const nested = findNestedError(record[k], depth + 1, seen)
+
+    if (nested) {return nested}
+  }
+
+  return ''
+}
+
+export function formatToolResultSummary(value: unknown): string {
+  return formatSummaryValue(unwrapPayload(value), 0) || formatSummaryValue(value, 0)
+}
+
+export function extractToolErrorMessage(value: unknown): string {
+  return findNestedError(value, 0, new Set())
+}