Merge pull request #475 from rahthakor/feature/ui-enhancements

feat(ui): refactor chat layout with sidebar, message grouping, and nav improvements
2026-01-09 18:54:44 +00:00
parent 6ec4c4bf8f 067c20608c
commit 47a8b410ee
23 changed files with 2560 additions and 314 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -69,6 +69,7 @@
 - Sessions: support session `label` in store/list/UI and allow `sessions_send` lookup by label. (#570) — thanks @azade-c
 - Control UI: show/patch per-session reasoning level and render extracted reasoning in chat.
 - Control UI: queue outgoing chat messages, add Enter-to-send, and show queued items. (#527) — thanks @YuriNachos
+- Control UI: refactor chat layout with tool sidebar, grouped messages, and nav improvements. (#475) — thanks @rahthakor
 - Control UI: drop explicit `ui:install` step; `ui:build` now auto-installs UI deps (docs + update flow).
 - Telegram: retry long-polling conflicts with backoff to avoid fatal exits.
 - Telegram: fix grammY fetch type mismatch when injecting `fetch`. (#512) — thanks @YuriNachos
--- a/src/agents/bash-tools.test.ts
+++ b/src/agents/bash-tools.test.ts
@@ -1,4 +1,4 @@
-import { beforeEach, describe, expect, it } from "vitest";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { resetProcessRegistryForTests } from "./bash-process-registry.js";
 import {
  bashTool,
@@ -50,6 +50,16 @@ beforeEach(() => {
 });

 describe("bash tool backgrounding", () => {
+  const originalShell = process.env.SHELL;
+
+  beforeEach(() => {
+    if (!isWin) process.env.SHELL = "/bin/bash";
+  });
+
+  afterEach(() => {
+    if (!isWin) process.env.SHELL = originalShell;
+  });
+
  it(
    "backgrounds after yield and can be polled",
    async () => {
--- a/ui/index.html
+++ b/ui/index.html
@@ -12,4 +12,3 @@
    <script type="module" src="/src/main.ts"></script>
  </body>
 </html>
-
--- a/ui/src/styles/base.css
+++ b/ui/src/styles/base.css
@@ -94,29 +94,7 @@ body::before {
  z-index: 0;
 }

-body::after {
-  content: "";
-  position: fixed;
-  inset: 0;
-  background:
-    repeating-linear-gradient(
-      90deg,
-      var(--grid-line) 0,
-      var(--grid-line) 1px,
-      transparent 1px,
-      transparent 140px
-    ),
-    repeating-linear-gradient(
-      0deg,
-      var(--grid-line) 0,
-      var(--grid-line) 1px,
-      transparent 1px,
-      transparent 140px
-    );
-  opacity: 0.45;
-  pointer-events: none;
-  z-index: 0;
-}
+/* Grid overlay removed for cleaner look */

@keyframes theme-circle-transition {
  0% {
--- a/ui/src/styles/chat.css
+++ b/ui/src/styles/chat.css
@@ -0,0 +1,789 @@
+/* =============================================
+   CHAT CARD LAYOUT - Flex container with sticky compose
+   ============================================= */
+
+/* Main chat card - flex column layout, transparent background */
+.chat {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  flex: 1 1 0;
+  height: 100%;
+  min-height: 0; /* Allow flex shrinking */
+  overflow: hidden;
+  background: transparent !important;
+  border: none !important;
+  box-shadow: none !important;
+}
+
+/* Chat header - fixed at top, transparent */
+.chat-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: 12px;
+  flex-wrap: nowrap;
+  flex-shrink: 0;
+  padding-bottom: 12px;
+  margin-bottom: 12px;
+  background: transparent;
+}
+
+.chat-header__left {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  flex-wrap: wrap;
+  min-width: 0;
+}
+
+.chat-header__right {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.chat-session {
+  min-width: 180px;
+}
+
+/* Chat thread - scrollable middle section, transparent */
+.chat-thread {
+  flex: 1 1 0; /* Grow, shrink, and use 0 base for proper scrolling */
+  overflow-y: auto;
+  overflow-x: hidden;
+  padding: 12px;
+  margin: 0 -12px;
+  min-height: 0; /* Allow shrinking for flex scroll behavior */
+  border-radius: 12px;
+  background: transparent;
+}
+
+/* Focus mode exit button */
+.chat-focus-exit {
+  position: absolute;
+  top: 12px;
+  right: 12px;
+  z-index: 100;
+  width: 32px;
+  height: 32px;
+  border-radius: 50%;
+  border: 1px solid var(--border);
+  background: var(--panel);
+  color: var(--muted);
+  font-size: 20px;
+  line-height: 1;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  transition: background 150ms ease-out, color 150ms ease-out, border-color 150ms ease-out;
+  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
+}
+
+.chat-focus-exit:hover {
+  background: var(--panel-strong);
+  color: var(--text);
+  border-color: var(--accent);
+}
+
+/* Chat compose - sticky at bottom */
+.chat-compose {
+  position: sticky;
+  bottom: 0;
+  flex-shrink: 0;
+  display: flex;
+  align-items: flex-end;
+  gap: 12px;
+  margin-top: auto; /* Push to bottom of flex container */
+  padding: 16px 0 4px;
+  background: linear-gradient(to bottom, transparent, var(--bg) 20%);
+  z-index: 10;
+}
+
+.chat-compose__field {
+  flex: 1 1 auto;
+  min-width: 0;
+}
+
+/* Hide the "Message" label - keep textarea only */
+.chat-compose__field > span {
+  display: none;
+}
+
+/* Override .field textarea min-height (180px) from components.css */
+.chat-compose .chat-compose__field textarea {
+  width: 100%;
+  min-height: 36px;
+  max-height: 150px;
+  padding: 8px 12px;
+  border-radius: 10px;
+  resize: vertical;
+  white-space: pre-wrap;
+  font-family: var(--font-body);
+  font-size: 14px;
+  line-height: 1.45;
+}
+
+.chat-compose__field textarea:disabled {
+  opacity: 0.7;
+  cursor: not-allowed;
+}
+
+.chat-compose__actions {
+  flex-shrink: 0;
+  display: flex;
+  align-items: stretch;
+}
+
+.chat-compose .chat-compose__actions .btn {
+  padding: 8px 16px;
+  font-size: 13px;
+  min-height: 36px;
+  white-space: nowrap;
+}
+
+/* Chat controls - moved to content-header area, left aligned */
+.chat-controls {
+  display: flex;
+  align-items: center;
+  justify-content: flex-start;
+  gap: 12px;
+  flex-wrap: wrap;
+}
+
+.chat-controls__session {
+  min-width: 140px;
+}
+
+.chat-controls__thinking {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  font-size: 13px;
+}
+
+/* Icon button style */
+.btn--icon {
+  padding: 8px !important;
+  min-width: 36px;
+  height: 36px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  border: 1px solid var(--border);
+  background: rgba(255, 255, 255, 0.06);
+}
+
+/* Controls separator */
+.chat-controls__separator {
+  color: rgba(255, 255, 255, 0.4);
+  font-size: 18px;
+  margin: 0 8px;
+  font-weight: 300;
+}
+
+:root[data-theme="light"] .chat-controls__separator {
+  color: rgba(16, 24, 40, 0.3);
+}
+
+.btn--icon:hover {
+  background: rgba(255, 255, 255, 0.12);
+  border-color: rgba(255, 255, 255, 0.2);
+}
+
+/* Light theme icon button overrides */
+:root[data-theme="light"] .btn--icon {
+  background: rgba(255, 255, 255, 0.9);
+  border-color: rgba(16, 24, 40, 0.2);
+  box-shadow: 0 1px 2px rgba(16, 24, 40, 0.05);
+  color: rgba(16, 24, 40, 0.7);
+}
+
+:root[data-theme="light"] .btn--icon:hover {
+  background: rgba(255, 255, 255, 1);
+  border-color: rgba(16, 24, 40, 0.3);
+  color: rgba(16, 24, 40, 0.9);
+}
+
+.btn--icon svg {
+  display: block;
+}
+
+.chat-controls__session select {
+  padding: 6px 10px;
+  font-size: 13px;
+}
+
+.chat-controls__thinking {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  font-size: 12px;
+  padding: 4px 10px;
+  background: rgba(255, 255, 255, 0.04);
+  border-radius: 6px;
+  border: 1px solid var(--border);
+}
+
+/* Light theme thinking indicator override */
+:root[data-theme="light"] .chat-controls__thinking {
+  background: rgba(255, 255, 255, 0.9);
+  border-color: rgba(16, 24, 40, 0.15);
+}
+
+@media (max-width: 640px) {
+  .chat-session {
+    min-width: 140px;
+  }
+
+  .chat-compose {
+    grid-template-columns: 1fr;
+  }
+
+  .chat-controls {
+    flex-wrap: wrap;
+    gap: 8px;
+  }
+
+  .chat-controls__session {
+    min-width: 120px;
+  }
+}
+
+/* =============================================
+   LEGACY CHAT LINE LAYOUT (non-grouped)
+   ============================================= */
+
+.chat-line {
+  display: flex;
+  margin-bottom: 12px;
+}
+
+.chat-line.user {
+  justify-content: flex-end;
+}
+
+.chat-line.assistant,
+.chat-line.other {
+  justify-content: flex-start;
+}
+
+.chat-msg {
+  display: grid;
+  gap: 6px;
+  max-width: min(900px, 95%);
+}
+
+.chat-line.user .chat-msg {
+  justify-items: end;
+}
+
+.chat-stamp {
+  font-size: 11px;
+  color: var(--muted);
+}
+
+.chat-line.user .chat-stamp {
+  text-align: right;
+}
+
+/* =============================================
+   CHAT TEXT STYLING
+   ============================================= */
+
+.chat-text {
+  font-size: 14px;
+  line-height: 1.5;
+  word-wrap: break-word;
+  overflow-wrap: break-word;
+}
+
+.chat-text :where(p, ul, ol, pre, blockquote, table) {
+  margin: 0;
+}
+
+.chat-text :where(p + p, p + ul, p + ol, p + pre, p + blockquote) {
+  margin-top: 0.75em;
+}
+
+.chat-text :where(ul, ol) {
+  padding-left: 1.5em;
+}
+
+.chat-text :where(li + li) {
+  margin-top: 0.25em;
+}
+
+.chat-text :where(a) {
+  color: var(--accent);
+  text-decoration: underline;
+  text-underline-offset: 2px;
+}
+
+.chat-text :where(a:hover) {
+  opacity: 0.8;
+}
+
+.chat-text :where(code) {
+  font-family: var(--mono);
+  font-size: 0.9em;
+}
+
+.chat-text :where(:not(pre) > code) {
+  background: rgba(0, 0, 0, 0.15);
+  padding: 0.15em 0.4em;
+  border-radius: 4px;
+}
+
+.chat-text :where(pre) {
+  background: rgba(0, 0, 0, 0.15);
+  border-radius: 6px;
+  padding: 10px 12px;
+  overflow-x: auto;
+}
+
+.chat-text :where(pre code) {
+  background: none;
+  padding: 0;
+}
+
+.chat-text :where(blockquote) {
+  border-left: 3px solid var(--border);
+  padding-left: 12px;
+  color: var(--muted);
+}
+
+.chat-text :where(hr) {
+  border: none;
+  border-top: 1px solid var(--border);
+  margin: 1em 0;
+}
+
+/* =============================================
+   GROUPED CHAT LAYOUT (Slack-style)
+   ============================================= */
+
+/* Chat Group Layout - default (assistant/other on left) */
+.chat-group {
+  display: flex;
+  gap: 12px;
+  align-items: flex-start;
+  margin-bottom: 16px;
+  margin-left: 16px;
+  margin-right: 16px;
+}
+
+/* User messages on right */
+.chat-group.user {
+  flex-direction: row-reverse;
+  justify-content: flex-start;
+}
+
+.chat-group-messages {
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+  max-width: min(900px, calc(100% - 60px));
+}
+
+/* User messages align content right */
+.chat-group.user .chat-group-messages {
+  align-items: flex-end;
+}
+
+.chat-group.user .chat-group-footer {
+  justify-content: flex-end;
+}
+
+/* Footer at bottom of message group (role + time) */
+.chat-group-footer {
+  display: flex;
+  gap: 8px;
+  align-items: baseline;
+  margin-top: 6px;
+}
+
+.chat-sender-name {
+  font-weight: 500;
+  font-size: 12px;
+  color: var(--muted);
+}
+
+.chat-group-timestamp {
+  font-size: 11px;
+  color: var(--muted);
+  opacity: 0.7;
+}
+
+/* Avatar Styles */
+.chat-avatar {
+  width: 40px;
+  height: 40px;
+  border-radius: 8px;
+  background: var(--panel-strong);
+  display: grid;
+  place-items: center;
+  font-weight: 600;
+  font-size: 14px;
+  flex-shrink: 0;
+  align-self: flex-end; /* Align with last message in group */
+  margin-bottom: 4px; /* Optical alignment */
+}
+
+.chat-avatar.user {
+  background: rgba(245, 159, 74, 0.2);
+  color: rgba(245, 159, 74, 1);
+}
+
+.chat-avatar.assistant {
+  background: rgba(52, 199, 183, 0.2);
+  color: rgba(52, 199, 183, 1);
+}
+
+.chat-avatar.other {
+  background: rgba(150, 150, 150, 0.2);
+  color: rgba(150, 150, 150, 1);
+}
+
+/* Minimal Bubble Design - dynamic width based on content */
+.chat-bubble {
+  display: inline-block;
+  border: 1px solid var(--border);
+  background: rgba(0, 0, 0, 0.12);
+  border-radius: 12px;
+  padding: 10px 14px;
+  box-shadow: none;
+  transition: background 150ms ease-out, border-color 150ms ease-out;
+  max-width: 100%;
+  word-wrap: break-word;
+}
+
+.chat-bubble:hover {
+  background: rgba(0, 0, 0, 0.18);
+}
+
+/* User bubbles have different styling */
+.chat-group.user .chat-bubble {
+  background: rgba(245, 159, 74, 0.15);
+  border-color: rgba(245, 159, 74, 0.3);
+}
+
+.chat-group.user .chat-bubble:hover {
+  background: rgba(245, 159, 74, 0.22);
+}
+
+/* Streaming animation */
+.chat-bubble.streaming {
+  animation: pulsing-border 1.5s ease-out infinite;
+}
+
+@keyframes pulsing-border {
+  0%, 100% {
+    border-color: var(--border);
+  }
+  50% {
+    border-color: var(--accent);
+  }
+}
+
+/* Fade-in animation for new messages */
+.chat-bubble.fade-in {
+  animation: fade-in 200ms ease-out;
+}
+
+@keyframes fade-in {
+  from {
+    opacity: 0;
+    transform: translateY(4px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}
+
+/* Tool Card Styles */
+.chat-tool-card {
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  padding: 12px;
+  margin-top: 8px;
+  transition: border-color 150ms ease-out, background 150ms ease-out;
+  /* Fixed max-height to ensure cards don't expand too much */
+  max-height: 120px;
+  overflow: hidden;
+}
+
+.chat-tool-card:hover {
+  border-color: var(--accent);
+  background: rgba(0, 0, 0, 0.06);
+}
+
+/* First tool card in a group - no top margin */
+.chat-tool-card:first-child {
+  margin-top: 0;
+}
+
+.chat-tool-card--clickable {
+  cursor: pointer;
+}
+
+.chat-tool-card--clickable:focus {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+}
+
+/* Header with title and chevron */
+.chat-tool-card__header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: 8px;
+}
+
+.chat-tool-card__title {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  font-weight: 600;
+  font-size: 13px;
+  line-height: 1.2;
+}
+
+.chat-tool-card__icon {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 18px;
+  height: 18px;
+  font-size: 14px;
+  line-height: 1;
+  font-family: "Apple Color Emoji", "Segoe UI Emoji", "Noto Color Emoji", sans-serif;
+  vertical-align: middle;
+  flex-shrink: 0;
+}
+
+/* "View >" action link */
+.chat-tool-card__action {
+  font-size: 12px;
+  color: var(--accent);
+  opacity: 0.8;
+  transition: opacity 150ms ease-out;
+}
+
+.chat-tool-card--clickable:hover .chat-tool-card__action {
+  opacity: 1;
+}
+
+/* Status indicator for completed/empty results */
+.chat-tool-card__status {
+  font-size: 14px;
+  color: var(--ok);
+}
+
+.chat-tool-card__status-text {
+  font-size: 11px;
+  margin-top: 4px;
+}
+
+.chat-tool-card__detail {
+  font-size: 12px;
+  color: var(--muted);
+  margin-top: 4px;
+}
+
+/* Collapsed preview - fixed height with truncation */
+.chat-tool-card__preview {
+  font-size: 11px;
+  color: var(--muted);
+  margin-top: 8px;
+  padding: 8px 10px;
+  background: rgba(0, 0, 0, 0.08);
+  border-radius: 6px;
+  white-space: pre-wrap;
+  overflow: hidden;
+  max-height: 44px;
+  line-height: 1.4;
+  border: 1px solid rgba(255, 255, 255, 0.04);
+}
+
+.chat-tool-card--clickable:hover .chat-tool-card__preview {
+  background: rgba(0, 0, 0, 0.12);
+  border-color: rgba(255, 255, 255, 0.08);
+}
+
+/* Short inline output */
+.chat-tool-card__inline {
+  font-size: 11px;
+  color: var(--text);
+  margin-top: 6px;
+  padding: 6px 8px;
+  background: rgba(0, 0, 0, 0.06);
+  border-radius: 4px;
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+
+/* Reading Indicator */
+.chat-reading-indicator {
+  background: transparent;
+  border: 1px solid var(--border);
+  padding: 12px;
+  display: inline-flex;
+}
+
+.chat-reading-indicator__dots {
+  display: flex;
+  gap: 6px;
+  align-items: center;
+}
+
+.chat-reading-indicator__dots span {
+  width: 6px;
+  height: 6px;
+  border-radius: 50%;
+  background: var(--muted);
+  animation: reading-pulse 1.4s ease-in-out infinite;
+}
+
+.chat-reading-indicator__dots span:nth-child(1) {
+  animation-delay: 0s;
+}
+
+.chat-reading-indicator__dots span:nth-child(2) {
+  animation-delay: 0.2s;
+}
+
+.chat-reading-indicator__dots span:nth-child(3) {
+  animation-delay: 0.4s;
+}
+
+@keyframes reading-pulse {
+  0%, 60%, 100% {
+    opacity: 0.3;
+    transform: scale(0.8);
+  }
+  30% {
+    opacity: 1;
+    transform: scale(1);
+  }
+}
+
+/* Split View Layout */
+.chat-split-container {
+  display: flex;
+  gap: 0;
+  flex: 1;
+  min-height: 0;
+  height: 100%;
+}
+
+.chat-main {
+  min-width: 400px;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+  /* Smooth transition when sidebar opens/closes */
+  transition: flex 250ms ease-out;
+}
+
+.chat-sidebar {
+  flex: 1;
+  min-width: 300px;
+  border-left: 1px solid var(--border);
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+  animation: slide-in 200ms ease-out;
+}
+
+@keyframes slide-in {
+  from {
+    opacity: 0;
+    transform: translateX(20px);
+  }
+  to {
+    opacity: 1;
+    transform: translateX(0);
+  }
+}
+
+/* Sidebar Panel */
+.sidebar-panel {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+  background: var(--panel);
+}
+
+.sidebar-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 12px 16px;
+  border-bottom: 1px solid var(--border);
+  flex-shrink: 0;
+  position: sticky;
+  top: 0;
+  z-index: 10;
+  background: var(--panel);
+}
+
+/* Smaller close button for sidebar */
+.sidebar-header .btn {
+  padding: 4px 8px;
+  font-size: 14px;
+  min-width: auto;
+  line-height: 1;
+}
+
+.sidebar-title {
+  font-weight: 600;
+  font-size: 14px;
+}
+
+.sidebar-content {
+  flex: 1;
+  overflow: auto;
+  padding: 16px;
+}
+
+.sidebar-markdown {
+  font-size: 14px;
+  line-height: 1.5;
+}
+
+.sidebar-markdown pre {
+  background: rgba(0, 0, 0, 0.12);
+  border-radius: 4px;
+  padding: 12px;
+  overflow-x: auto;
+}
+
+.sidebar-markdown code {
+  font-family: var(--mono);
+  font-size: 13px;
+}
+
+/* Mobile: Full-screen modal */
+@media (max-width: 768px) {
+  .chat-split-container {
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    z-index: 1000;
+  }
+
+  .chat-main {
+    display: none; /* Hide chat on mobile when sidebar open */
+  }
+
+  .chat-sidebar {
+    width: 100%;
+    min-width: 0;
+    border-left: none;
+  }
+}
--- a/ui/src/styles/components.css
+++ b/ui/src/styles/components.css
@@ -1,3 +1,5 @@
+@import './chat.css';
+
 .card {
  border: 1px solid var(--border);
  background: linear-gradient(160deg, rgba(255, 255, 255, 0.04), transparent 65%),
@@ -210,6 +212,17 @@
  background: rgba(255, 107, 107, 0.18);
 }

+.btn--sm {
+  padding: 5px 10px;
+  font-size: 12px;
+}
+
+.btn:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
+  transform: none;
+}
+
 .field {
  display: grid;
  gap: 6px;
@@ -287,8 +300,9 @@
 :root[data-theme="light"] .field input,
 :root[data-theme="light"] .field textarea,
 :root[data-theme="light"] .field select {
-  background: rgba(255, 255, 255, 0.9);
-  border-color: var(--border-strong);
+  background: rgba(255, 255, 255, 1);
+  border-color: rgba(16, 24, 40, 0.25);
+  box-shadow: 0 1px 2px rgba(16, 24, 40, 0.06);
 }

 :root[data-theme="light"] .field input:focus,
@@ -297,6 +311,26 @@
  background: #ffffff;
 }

+/* Light theme button overrides */
+:root[data-theme="light"] .btn {
+  background: rgba(255, 255, 255, 0.9);
+  border-color: rgba(16, 24, 40, 0.2);
+  box-shadow: 0 1px 2px rgba(16, 24, 40, 0.05);
+}
+
+:root[data-theme="light"] .btn:hover {
+  background: rgba(255, 255, 255, 1);
+  border-color: rgba(16, 24, 40, 0.3);
+}
+
+:root[data-theme="light"] .btn.primary {
+  background: rgba(245, 159, 74, 0.15);
+}
+
+:root[data-theme="light"] .btn.active {
+  background: rgba(245, 159, 74, 0.12);
+}
+
 .muted {
  color: var(--muted);
 }
@@ -569,6 +603,7 @@

 .shell--chat .chat {
  flex: 1;
+  max-height: calc(100vh - 180px); /* Constrain height for sticky compose */
 }

 .chat-header {
@@ -603,26 +638,18 @@
  flex-direction: column;
  gap: 12px;
  flex: 1;
-  max-height: none;
-  overflow: visible;
+  min-height: 0; /* Allow flex shrinking for scroll behavior */
+  overflow-y: auto; /* Enable scrolling */
+  overflow-x: hidden;
  padding: 14px 12px;
  min-width: 0;
-  border-radius: 16px;
-  border: 1px solid var(--border);
-  background: linear-gradient(
-    180deg,
-    rgba(0, 0, 0, 0.2) 0%,
-    rgba(0, 0, 0, 0.3) 100%
-  );
+  border-radius: 0;
+  border: none;
+  background: transparent;
 }

 :root[data-theme="light"] .chat-thread {
-  border-color: rgba(16, 24, 40, 0.12);
-  background: linear-gradient(
-    180deg,
-    rgba(16, 24, 40, 0.03) 0%,
-    rgba(16, 24, 40, 0.06) 100%
-  );
+  background: transparent;
 }

 .chat-queue {
--- a/ui/src/styles/layout.css
+++ b/ui/src/styles/layout.css
@@ -1,28 +1,28 @@
 .shell {
-  --shell-pad: 18px;
-  --shell-gap: 18px;
-  --shell-nav-col: minmax(220px, 280px);
-  --shell-topbar-row: auto;
+  --shell-pad: 16px;
+  --shell-gap: 16px;
+  --shell-nav-width: 220px;
+  --shell-topbar-height: 56px;
  --shell-focus-duration: 220ms;
  --shell-focus-ease: cubic-bezier(0.2, 0.85, 0.25, 1);
  min-height: 100vh;
  display: grid;
-  grid-template-columns: var(--shell-nav-col) minmax(0, 1fr);
-  grid-template-rows: var(--shell-topbar-row) 1fr;
+  grid-template-columns: var(--shell-nav-width) minmax(0, 1fr);
+  grid-template-rows: var(--shell-topbar-height) 1fr;
  grid-template-areas:
    "topbar topbar"
    "nav content";
-  gap: var(--shell-gap);
-  padding: var(--shell-pad);
+  gap: 0;
  animation: dashboard-enter 0.6s ease-out;
-  transition: padding var(--shell-focus-duration) var(--shell-focus-ease);
+  transition: grid-template-columns var(--shell-focus-duration) var(--shell-focus-ease);
+}
+
+.shell--nav-collapsed {
+  grid-template-columns: 0px minmax(0, 1fr);
 }

 .shell--chat-focus {
-  --shell-pad: 8px;
-  --shell-gap: 0px;
-  --shell-nav-col: 0px;
-  --shell-topbar-row: auto;
+  grid-template-columns: 0px minmax(0, 1fr);
 }

 .shell--chat-focus .content {
@@ -33,89 +33,147 @@
 .topbar {
  grid-area: topbar;
  position: sticky;
-  top: var(--shell-pad);
-  z-index: 20;
+  top: 0;
+  z-index: 40;
  display: flex;
  justify-content: space-between;
  align-items: center;
-  padding: 16px 20px;
-  border: 1px solid var(--border);
-  border-radius: 18px;
-  background: linear-gradient(135deg, var(--chrome), rgba(255, 255, 255, 0.02));
+  gap: 16px;
+  padding: 0 20px;
+  height: var(--shell-topbar-height);
+  border-bottom: 1px solid var(--border);
+  background: var(--panel);
  backdrop-filter: blur(18px);
-  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.28);
-  overflow: hidden;
-  transform-origin: top center;
-  transition: opacity var(--shell-focus-duration) var(--shell-focus-ease),
-    transform var(--shell-focus-duration) var(--shell-focus-ease),
-    max-height var(--shell-focus-duration) var(--shell-focus-ease),
-    padding var(--shell-focus-duration) var(--shell-focus-ease),
-    border-width var(--shell-focus-duration) var(--shell-focus-ease);
-  max-height: max(0px, var(--topbar-height, 92px));
+}
+
+.topbar-left {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+}
+
+.topbar .nav-collapse-toggle {
+  width: 44px;
+  height: 44px;
+  margin-bottom: 0;
+}
+
+.topbar .nav-collapse-toggle__icon {
+  font-size: 22px;
 }

 .brand {
-  display: grid;
-  gap: 4px;
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
 }

 .brand-title {
  font-family: var(--font-display);
-  font-size: 20px;
-  letter-spacing: 0.6px;
+  font-size: 16px;
+  letter-spacing: 1px;
  text-transform: uppercase;
+  font-weight: 600;
+  line-height: 1.1;
 }

 .brand-sub {
+  font-size: 10px;
  color: var(--muted);
-  font-size: 12px;
-  letter-spacing: 1.2px;
+  letter-spacing: 0.8px;
  text-transform: uppercase;
+  line-height: 1;
 }

 .topbar-status {
  display: flex;
  align-items: center;
-  gap: 10px;
+  gap: 8px;
+}
+
+/* Smaller pill and theme toggle in topbar */
+.topbar-status .pill {
+  padding: 4px 10px;
+  gap: 6px;
+  font-size: 11px;
+}
+
+.topbar-status .statusDot {
+  width: 6px;
+  height: 6px;
+}
+
+.topbar-status .theme-toggle {
+  --theme-item: 22px;
+  --theme-gap: 4px;
+  --theme-pad: 4px;
+}
+
+.topbar-status .theme-icon {
+  width: 12px;
+  height: 12px;
 }

 .nav {
  grid-area: nav;
-  position: sticky;
-  top: calc(
-    var(--shell-pad) + var(--topbar-height, 0px) + var(--shell-gap)
-  );
-  align-self: start;
-  max-height: calc(
-    100vh - var(--topbar-height, 0px) - var(--shell-gap) -
-      var(--shell-pad) - var(--shell-pad)
-  );
-  overflow: auto;
+  overflow-y: auto;
+  overflow-x: hidden;
  padding: 16px;
-  border: 1px solid var(--border);
-  border-radius: 20px;
+  border-right: 1px solid var(--border);
  background: var(--panel);
-  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.25);
  backdrop-filter: blur(18px);
-  transform-origin: left center;
-  transition: opacity var(--shell-focus-duration) var(--shell-focus-ease),
-    transform var(--shell-focus-duration) var(--shell-focus-ease),
-    max-width var(--shell-focus-duration) var(--shell-focus-ease),
-    padding var(--shell-focus-duration) var(--shell-focus-ease),
-    border-width var(--shell-focus-duration) var(--shell-focus-ease);
-  max-width: 320px;
+  transition: width var(--shell-focus-duration) var(--shell-focus-ease),
+    padding var(--shell-focus-duration) var(--shell-focus-ease);
 }

 .shell--chat-focus .nav {
-  opacity: 0;
-  transform: translateX(-12px);
-  max-width: 0px;
+  width: 0;
  padding: 0;
  border-width: 0;
  overflow: hidden;
  pointer-events: none;
 }

+/* Collapsed nav sidebar - completely hidden */
+.nav--collapsed {
+  width: 0;
+  min-width: 0;
+  padding: 0;
+  overflow: hidden;
+  border: none;
+  opacity: 0;
+  pointer-events: none;
+}
+
+/* Nav collapse toggle button */
+.nav-collapse-toggle {
+  width: 32px;
+  height: 32px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: transparent;
+  border: 1px solid transparent;
+  border-radius: 6px;
+  cursor: pointer;
+  transition: background 150ms ease, border-color 150ms ease;
+  margin-bottom: 16px;
+}
+
+.nav-collapse-toggle:hover {
+  background: rgba(255, 255, 255, 0.08);
+  border-color: var(--border);
+}
+
+:root[data-theme="light"] .nav-collapse-toggle:hover {
+  background: rgba(0, 0, 0, 0.06);
+}
+
+.nav-collapse-toggle__icon {
+  font-size: 16px;
+  color: var(--muted);
+}
+
 .nav-group {
  margin-bottom: 18px;
  display: grid;
@@ -130,27 +188,77 @@
  border-bottom: none;
 }

+.nav-group__items {
+  display: grid;
+  gap: 4px;
+}
+
+.nav-group--collapsed .nav-group__items {
+  display: none;
+}
+
 .nav-label {
-  font-size: 10px;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 8px;
+  width: 100%;
+  padding: 4px 0;
+  font-size: 11px;
+  font-weight: 500;
  text-transform: uppercase;
-  letter-spacing: 1.6px;
-  color: var(--muted);
+  letter-spacing: 1.4px;
+  color: var(--text);
+  opacity: 0.7;
+  margin-bottom: 4px;
+  background: transparent;
+  border: none;
+  cursor: pointer;
+  text-align: left;
+}
+
+.nav-label:hover {
+  opacity: 1;
+}
+
+.nav-label__text {
+  flex: 1;
+}
+
+.nav-label__chevron {
+  font-size: 12px;
+  opacity: 0.6;
 }

 .nav-item {
  position: relative;
  display: flex;
  align-items: center;
-  justify-content: space-between;
-  gap: 10px;
+  justify-content: flex-start;
+  gap: 8px;
  padding: 10px 12px 10px 14px;
  border-radius: 12px;
  border: 1px solid transparent;
-  background: rgba(255, 255, 255, 0.02);
+  background: transparent;
  color: var(--muted);
  cursor: pointer;
-  transition: border-color 160ms ease, background 160ms ease, color 160ms ease,
-    transform 160ms ease;
+  text-decoration: none;
+  transition: border-color 160ms ease, background 160ms ease, color 160ms ease;
+}
+
+.nav-item__icon {
+  font-size: 16px;
+  width: 18px;
+  height: 18px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  flex-shrink: 0;
+}
+
+.nav-item__text {
+  font-size: 13px;
+  white-space: nowrap;
 }

 .nav-item:hover {
@@ -162,11 +270,11 @@
 .nav-item::before {
  content: "";
  position: absolute;
-  left: 6px;
+  left: 0;
  top: 50%;
  width: 4px;
  height: 60%;
-  border-radius: 999px;
+  border-radius: 0 999px 999px 0;
  transform: translateY(-50%);
  background: transparent;
 }
@@ -174,8 +282,7 @@
 .nav-item.active {
  color: var(--text);
  border-color: rgba(245, 159, 74, 0.45);
-  background: rgba(245, 159, 74, 0.16);
-  transform: translateX(2px);
+  background: rgba(245, 159, 74, 0.12);
 }

 .nav-item.active::before {
@@ -190,13 +297,12 @@
  flex-direction: column;
  gap: 20px;
  min-height: 0;
+  overflow-y: auto; /* Enable vertical scrolling for pages with long content */
+  overflow-x: hidden;
 }

 .shell--chat .content {
-  min-height: calc(
-    100vh - var(--topbar-height, 0px) - var(--shell-gap) -
-      var(--shell-pad) - var(--shell-pad)
-  );
+  /* No-op: keep chat layout consistent with other tabs */
 }

 .docs-link {
@@ -264,6 +370,26 @@
  gap: 10px;
 }

+/* Chat view: header and controls side by side */
+.content--chat .content-header {
+  flex-direction: row;
+  align-items: center;
+  justify-content: space-between;
+  gap: 16px;
+}
+
+.content--chat .content-header > div:first-child {
+  text-align: left;
+}
+
+.content--chat .page-meta {
+  justify-content: flex-start;
+}
+
+.content--chat .chat-controls {
+  flex-shrink: 0;
+}
+
 .grid {
  display: grid;
  gap: 18px;
--- a/ui/src/ui/app-render.ts
+++ b/ui/src/ui/app-render.ts
@@ -3,6 +3,7 @@ import { html, nothing } from "lit";
 import type { GatewayBrowserClient, GatewayHelloOk } from "./gateway";
 import {
  TAB_GROUPS,
+  iconForTab,
  pathForTab,
  subtitleForTab,
  titleForTab,
@@ -215,11 +216,25 @@ export function renderApp(state: AppViewState) {
  const chatFocus = isChat && state.settings.chatFocusMode;

  return html`
-    <div class="shell ${isChat ? "shell--chat" : ""} ${chatFocus ? "shell--chat-focus" : ""}">
+    <div class="shell ${isChat ? "shell--chat" : ""} ${chatFocus ? "shell--chat-focus" : ""} ${state.settings.navCollapsed ? "shell--nav-collapsed" : ""}">
      <header class="topbar">
-        <div class="brand">
-          <div class="brand-title">Clawdbot Control</div>
-          <div class="brand-sub">Gateway dashboard</div>
+        <div class="topbar-left">
+          <button
+            class="nav-collapse-toggle"
+            @click=${() =>
+              state.applySettings({
+                ...state.settings,
+                navCollapsed: !state.settings.navCollapsed,
+              })}
+            title="${state.settings.navCollapsed ? "Expand sidebar" : "Collapse sidebar"}"
+            aria-label="${state.settings.navCollapsed ? "Expand sidebar" : "Collapse sidebar"}"
+          >
+            <span class="nav-collapse-toggle__icon">☰</span>
+          </button>
+          <div class="brand">
+            <div class="brand-title">CLAWDBOT</div>
+            <div class="brand-sub">Gateway Dashboard</div>
+          </div>
        </div>
        <div class="topbar-status">
          <div class="pill">
@@ -227,28 +242,36 @@ export function renderApp(state: AppViewState) {
            <span>Health</span>
            <span class="mono">${state.connected ? "OK" : "Offline"}</span>
          </div>
-          ${isChat
-            ? renderChatFocusToggle(
-                state.settings.chatFocusMode,
-                () =>
-                  state.applySettings({
-                    ...state.settings,
-                    chatFocusMode: !state.settings.chatFocusMode,
-                  }),
-              )
-            : nothing}
          ${renderThemeToggle(state)}
        </div>
      </header>
-      <aside class="nav">
-        ${TAB_GROUPS.map(
-          (group) => html`
-            <div class="nav-group">
-              <div class="nav-label">${group.label}</div>
-              ${group.tabs.map((tab) => renderTab(state, tab))}
+      <aside class="nav ${state.settings.navCollapsed ? "nav--collapsed" : ""}">
+        ${TAB_GROUPS.map((group) => {
+          const isGroupCollapsed = state.settings.navGroupsCollapsed[group.label] ?? false;
+          const hasActiveTab = group.tabs.some((tab) => tab === state.tab);
+          return html`
+            <div class="nav-group ${isGroupCollapsed && !hasActiveTab ? "nav-group--collapsed" : ""}">
+              <button
+                class="nav-label"
+                @click=${() => {
+                  const next = { ...state.settings.navGroupsCollapsed };
+                  next[group.label] = !isGroupCollapsed;
+                  state.applySettings({
+                    ...state.settings,
+                    navGroupsCollapsed: next,
+                  });
+                }}
+                aria-expanded=${!isGroupCollapsed}
+              >
+                <span class="nav-label__text">${group.label}</span>
+                <span class="nav-label__chevron">${isGroupCollapsed ? "+" : "−"}</span>
+              </button>
+              <div class="nav-group__items">
+                ${group.tabs.map((tab) => renderTab(state, tab))}
+              </div>
            </div>
-          `,
-        )}
+          `;
+        })}
      </aside>
      <main class="content ${isChat ? "content--chat" : ""}">
        <section class="content-header">
@@ -260,6 +283,7 @@ export function renderApp(state: AppViewState) {
            ${state.lastError
              ? html`<div class="pill danger">${state.lastError}</div>`
              : nothing}
+            ${isChat ? renderChatControls(state) : nothing}
          </div>
        </section>

@@ -453,15 +477,35 @@ export function renderApp(state: AppViewState) {
              isToolOutputExpanded: (id) => state.toolOutputExpanded.has(id),
              onToolOutputToggle: (id, expanded) =>
                state.toggleToolOutput(id, expanded),
+              focusMode: state.settings.chatFocusMode,
+              useNewChatLayout: state.settings.useNewChatLayout,
              onRefresh: () => {
                state.resetToolStream();
                return loadChatHistory(state);
              },
+              onToggleFocusMode: () =>
+                state.applySettings({
+                  ...state.settings,
+                  chatFocusMode: !state.settings.chatFocusMode,
+                }),
+              onToggleLayout: () =>
+                state.applySettings({
+                  ...state.settings,
+                  useNewChatLayout: !state.settings.useNewChatLayout,
+                }),
              onDraftChange: (next) => (state.chatMessage = next),
              onSend: () => state.handleSendChat(),
              onQueueRemove: (id) => state.removeQueuedMessage(id),
              onNewSession: () =>
                state.handleSendChat("/new", { restoreDraft: true }),
+              // Sidebar props for tool output viewing
+              sidebarOpen: state.sidebarOpen,
+              sidebarContent: state.sidebarContent,
+              sidebarError: state.sidebarError,
+              splitRatio: state.splitRatio,
+              onOpenSidebar: (content: string) => state.handleOpenSidebar(content),
+              onCloseSidebar: () => state.handleCloseSidebar(),
+              onSplitRatioChange: (ratio: number) => state.handleSplitRatioChange(ratio),
            })
          : nothing}

@@ -562,12 +606,115 @@ function renderTab(state: AppViewState, tab: Tab) {
        event.preventDefault();
        state.setTab(tab);
      }}
+      title=${titleForTab(tab)}
    >
-      <span>${titleForTab(tab)}</span>
+      <span class="nav-item__icon" aria-hidden="true">${iconForTab(tab)}</span>
+      <span class="nav-item__text">${titleForTab(tab)}</span>
    </a>
  `;
 }

+function renderChatControls(state: AppViewState) {
+  const sessionOptions = resolveSessionOptions(state.sessionKey, state.sessionsResult);
+  // Icon for list view (legacy)
+  const listIcon = html`<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="8" y1="6" x2="21" y2="6"></line><line x1="8" y1="12" x2="21" y2="12"></line><line x1="8" y1="18" x2="21" y2="18"></line><line x1="3" y1="6" x2="3.01" y2="6"></line><line x1="3" y1="12" x2="3.01" y2="12"></line><line x1="3" y1="18" x2="3.01" y2="18"></line></svg>`;
+  // Icon for grouped view
+  const groupIcon = html`<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><rect x="3" y="3" width="7" height="7"></rect><rect x="14" y="3" width="7" height="7"></rect><rect x="14" y="14" width="7" height="7"></rect><rect x="3" y="14" width="7" height="7"></rect></svg>`;
+  // Refresh icon
+  const refreshIcon = html`<svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 12a9 9 0 1 1-9-9c2.52 0 4.93 1 6.74 2.74L21 8"></path><path d="M21 3v5h-5"></path></svg>`;
+  const focusIcon = html`<svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M4 7V4h3"></path><path d="M20 7V4h-3"></path><path d="M4 17v3h3"></path><path d="M20 17v3h-3"></path><circle cx="12" cy="12" r="3"></circle></svg>`;
+  return html`
+    <div class="chat-controls">
+      <label class="field chat-controls__session">
+        <select
+          .value=${state.sessionKey}
+          ?disabled=${!state.connected}
+          @change=${(e: Event) => {
+            const next = (e.target as HTMLSelectElement).value;
+            state.sessionKey = next;
+            state.chatMessage = "";
+            state.chatStream = null;
+            state.chatStreamStartedAt = null;
+            state.chatRunId = null;
+            state.resetToolStream();
+            state.resetChatScroll();
+            state.applySettings({
+              ...state.settings,
+              sessionKey: next,
+              lastActiveSessionKey: next,
+            });
+            void loadChatHistory(state);
+          }}
+        >
+          ${sessionOptions.map(
+            (entry) =>
+              html`<option value=${entry.key}>
+                ${entry.displayName ?? entry.key}
+              </option>`,
+          )}
+        </select>
+      </label>
+      <button
+        class="btn btn--sm btn--icon"
+        ?disabled=${state.chatLoading || !state.connected}
+        @click=${() => {
+          state.resetToolStream();
+          void loadChatHistory(state);
+        }}
+        title="Refresh chat history"
+      >
+        ${refreshIcon}
+      </button>
+      <span class="chat-controls__separator">|</span>
+      <button
+        class="btn btn--sm btn--icon ${state.settings.chatFocusMode ? "active" : ""}"
+        @click=${() =>
+          state.applySettings({
+            ...state.settings,
+            chatFocusMode: !state.settings.chatFocusMode,
+          })}
+        aria-pressed=${state.settings.chatFocusMode}
+        title="Toggle focus mode (hide sidebar + page header)"
+      >
+        ${focusIcon}
+      </button>
+      <button
+        class="btn btn--sm btn--icon ${state.settings.useNewChatLayout ? "active" : ""}"
+        @click=${() =>
+          state.applySettings({
+            ...state.settings,
+            useNewChatLayout: !state.settings.useNewChatLayout,
+          })}
+        aria-pressed=${state.settings.useNewChatLayout}
+        title="${state.settings.useNewChatLayout ? "Switch to list view" : "Switch to grouped view"}"
+      >
+        ${state.settings.useNewChatLayout ? groupIcon : listIcon}
+      </button>
+    </div>
+  `;
+}
+
+function resolveSessionOptions(sessionKey: string, sessions: SessionsListResult | null) {
+  const seen = new Set<string>();
+  const options: Array<{ key: string; displayName?: string }> = [];
+
+  // Add current session key first
+  seen.add(sessionKey);
+  options.push({ key: sessionKey });
+
+  // Add sessions from the result
+  if (sessions?.sessions) {
+    for (const s of sessions.sessions) {
+      if (!seen.has(s.key)) {
+        seen.add(s.key);
+        options.push({ key: s.key, displayName: s.displayName });
+      }
+    }
+  }
+
+  return options;
+}
+
 const THEME_ORDER: ThemeMode[] = ["system", "light", "dark"];

 function renderThemeToggle(state: AppViewState) {
@@ -618,19 +765,6 @@ function renderThemeToggle(state: AppViewState) {
  `;
 }

-function renderChatFocusToggle(focusMode: boolean, onToggle: () => void) {
-  return html`
-    <button
-      class="btn ${focusMode ? "active" : ""}"
-      @click=${onToggle}
-      aria-pressed=${focusMode}
-      title="Toggle focus mode (hide sidebar + page header)"
-    >
-      Focus
-    </button>
-  `;
-}
-
 function renderSunIcon() {
  return html`
    <svg class="theme-icon" viewBox="0 0 24 24" aria-hidden="true">
--- a/ui/src/ui/app.ts
+++ b/ui/src/ui/app.ts
@@ -205,6 +205,7 @@ export class ClawdbotApp extends LitElement {
  @state() eventLog: EventLogEntry[] = [];
  private eventLogBuffer: EventLogEntry[] = [];
  private toolStreamSyncTimer: number | null = null;
+  private sidebarCloseTimer: number | null = null;

  @state() sessionKey = this.settings.sessionKey;
  @state() chatLoading = false;
@@ -218,6 +219,11 @@ export class ClawdbotApp extends LitElement {
  @state() chatThinkingLevel: string | null = null;
  @state() chatQueue: ChatQueueItem[] = [];
  @state() toolOutputExpanded = new Set<string>();
+  // Sidebar state for tool output viewing
+  @state() sidebarOpen = false;
+  @state() sidebarContent: string | null = null;
+  @state() sidebarError: string | null = null;
+  @state() splitRatio = this.settings.splitRatio;

  @state() nodesLoading = false;
  @state() nodes: Array<Record<string, unknown>> = [];
@@ -1149,6 +1155,37 @@ export class ClawdbotApp extends LitElement {
    await loadProviders(this, true);
  }

+  // Sidebar handlers for tool output viewing
+  handleOpenSidebar(content: string) {
+    if (this.sidebarCloseTimer != null) {
+      window.clearTimeout(this.sidebarCloseTimer);
+      this.sidebarCloseTimer = null;
+    }
+    this.sidebarContent = content;
+    this.sidebarError = null;
+    this.sidebarOpen = true;
+  }
+
+  handleCloseSidebar() {
+    this.sidebarOpen = false;
+    // Clear content after transition
+    if (this.sidebarCloseTimer != null) {
+      window.clearTimeout(this.sidebarCloseTimer);
+    }
+    this.sidebarCloseTimer = window.setTimeout(() => {
+      if (this.sidebarOpen) return;
+      this.sidebarContent = null;
+      this.sidebarError = null;
+      this.sidebarCloseTimer = null;
+    }, 200);
+  }
+
+  handleSplitRatioChange(ratio: number) {
+    const newRatio = Math.max(0.4, Math.min(0.7, ratio));
+    this.splitRatio = newRatio;
+    this.applySettings({ ...this.settings, splitRatio: newRatio });
+  }
+
  render() {
    return renderApp(this);
  }
--- a/ui/src/ui/chat-markdown.browser.test.ts
+++ b/ui/src/ui/chat-markdown.browser.test.ts
@@ -16,17 +16,24 @@ beforeEach(() => {
    // no-op: avoid real gateway WS connections in browser tests
  };
  window.__CLAWDBOT_CONTROL_UI_BASE_PATH__ = undefined;
+  localStorage.clear();
  document.body.innerHTML = "";
 });

 afterEach(() => {
  ClawdbotApp.prototype.connect = originalConnect;
  window.__CLAWDBOT_CONTROL_UI_BASE_PATH__ = undefined;
+  localStorage.clear();
  document.body.innerHTML = "";
 });

 describe("chat markdown rendering", () => {
  it("renders markdown inside tool result cards", async () => {
+    localStorage.setItem(
+      "clawdbot.control.settings.v1",
+      JSON.stringify({ useNewChatLayout: false }),
+    );
+
    const app = mountApp("/chat");
    await app.updateComplete;

--- a/ui/src/ui/chat/constants.ts
+++ b/ui/src/ui/chat/constants.ts
@@ -0,0 +1,12 @@
+/**
+ * Chat-related constants for the UI layer.
+ */
+
+/** Character threshold for showing tool output inline vs collapsed */
+export const TOOL_INLINE_THRESHOLD = 80;
+
+/** Maximum lines to show in collapsed preview */
+export const PREVIEW_MAX_LINES = 2;
+
+/** Maximum characters to show in collapsed preview */
+export const PREVIEW_MAX_CHARS = 100;
--- a/ui/src/ui/chat/message-normalizer.test.ts
+++ b/ui/src/ui/chat/message-normalizer.test.ts
@@ -0,0 +1,169 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import {
+  normalizeMessage,
+  normalizeRoleForGrouping,
+  isToolResultMessage,
+} from "./message-normalizer";
+
+describe("message-normalizer", () => {
+  describe("normalizeMessage", () => {
+    beforeEach(() => {
+      vi.useFakeTimers();
+      vi.setSystemTime(new Date("2024-01-01T00:00:00Z"));
+    });
+
+    afterEach(() => {
+      vi.useRealTimers();
+    });
+
+    it("normalizes message with string content", () => {
+      const result = normalizeMessage({
+        role: "user",
+        content: "Hello world",
+        timestamp: 1000,
+        id: "msg-1",
+      });
+
+      expect(result).toEqual({
+        role: "user",
+        content: [{ type: "text", text: "Hello world" }],
+        timestamp: 1000,
+        id: "msg-1",
+      });
+    });
+
+    it("normalizes message with array content", () => {
+      const result = normalizeMessage({
+        role: "assistant",
+        content: [
+          { type: "text", text: "Here is the result" },
+          { type: "tool_use", name: "bash", args: { command: "ls" } },
+        ],
+        timestamp: 2000,
+      });
+
+      expect(result.role).toBe("assistant");
+      expect(result.content).toHaveLength(2);
+      expect(result.content[0]).toEqual({ type: "text", text: "Here is the result", name: undefined, args: undefined });
+      expect(result.content[1]).toEqual({ type: "tool_use", text: undefined, name: "bash", args: { command: "ls" } });
+    });
+
+    it("normalizes message with text field (alternative format)", () => {
+      const result = normalizeMessage({
+        role: "user",
+        text: "Alternative format",
+      });
+
+      expect(result.content).toEqual([{ type: "text", text: "Alternative format" }]);
+    });
+
+    it("detects tool result by toolCallId", () => {
+      const result = normalizeMessage({
+        role: "assistant",
+        toolCallId: "call-123",
+        content: "Tool output",
+      });
+
+      expect(result.role).toBe("toolResult");
+    });
+
+    it("detects tool result by tool_call_id (snake_case)", () => {
+      const result = normalizeMessage({
+        role: "assistant",
+        tool_call_id: "call-456",
+        content: "Tool output",
+      });
+
+      expect(result.role).toBe("toolResult");
+    });
+
+    it("handles missing role", () => {
+      const result = normalizeMessage({ content: "No role" });
+      expect(result.role).toBe("unknown");
+    });
+
+    it("handles missing content", () => {
+      const result = normalizeMessage({ role: "user" });
+      expect(result.content).toEqual([]);
+    });
+
+    it("uses current timestamp when not provided", () => {
+      const result = normalizeMessage({ role: "user", content: "Test" });
+      expect(result.timestamp).toBe(Date.now());
+    });
+
+    it("handles arguments field (alternative to args)", () => {
+      const result = normalizeMessage({
+        role: "assistant",
+        content: [{ type: "tool_use", name: "test", arguments: { foo: "bar" } }],
+      });
+
+      expect(result.content[0].args).toEqual({ foo: "bar" });
+    });
+  });
+
+  describe("normalizeRoleForGrouping", () => {
+    it("returns assistant for toolresult", () => {
+      expect(normalizeRoleForGrouping("toolresult")).toBe("assistant");
+      expect(normalizeRoleForGrouping("toolResult")).toBe("assistant");
+      expect(normalizeRoleForGrouping("TOOLRESULT")).toBe("assistant");
+    });
+
+    it("returns assistant for tool_result", () => {
+      expect(normalizeRoleForGrouping("tool_result")).toBe("assistant");
+      expect(normalizeRoleForGrouping("TOOL_RESULT")).toBe("assistant");
+    });
+
+    it("returns assistant for tool", () => {
+      expect(normalizeRoleForGrouping("tool")).toBe("assistant");
+      expect(normalizeRoleForGrouping("Tool")).toBe("assistant");
+    });
+
+    it("returns assistant for function", () => {
+      expect(normalizeRoleForGrouping("function")).toBe("assistant");
+      expect(normalizeRoleForGrouping("Function")).toBe("assistant");
+    });
+
+    it("preserves user role", () => {
+      expect(normalizeRoleForGrouping("user")).toBe("user");
+      expect(normalizeRoleForGrouping("User")).toBe("User");
+    });
+
+    it("preserves assistant role", () => {
+      expect(normalizeRoleForGrouping("assistant")).toBe("assistant");
+    });
+
+    it("preserves system role", () => {
+      expect(normalizeRoleForGrouping("system")).toBe("system");
+    });
+  });
+
+  describe("isToolResultMessage", () => {
+    it("returns true for toolresult role", () => {
+      expect(isToolResultMessage({ role: "toolresult" })).toBe(true);
+      expect(isToolResultMessage({ role: "toolResult" })).toBe(true);
+      expect(isToolResultMessage({ role: "TOOLRESULT" })).toBe(true);
+    });
+
+    it("returns true for tool_result role", () => {
+      expect(isToolResultMessage({ role: "tool_result" })).toBe(true);
+      expect(isToolResultMessage({ role: "TOOL_RESULT" })).toBe(true);
+    });
+
+    it("returns false for other roles", () => {
+      expect(isToolResultMessage({ role: "user" })).toBe(false);
+      expect(isToolResultMessage({ role: "assistant" })).toBe(false);
+      expect(isToolResultMessage({ role: "tool" })).toBe(false);
+    });
+
+    it("returns false for missing role", () => {
+      expect(isToolResultMessage({})).toBe(false);
+      expect(isToolResultMessage({ content: "test" })).toBe(false);
+    });
+
+    it("returns false for non-string role", () => {
+      expect(isToolResultMessage({ role: 123 })).toBe(false);
+      expect(isToolResultMessage({ role: null })).toBe(false);
+    });
+  });
+});
--- a/ui/src/ui/chat/message-normalizer.ts
+++ b/ui/src/ui/chat/message-normalizer.ts
@@ -0,0 +1,69 @@
+/**
+ * Message normalization utilities for chat rendering.
+ */
+
+import type {
+  NormalizedMessage,
+  MessageContentItem,
+} from "../types/chat-types";
+
+/**
+ * Normalize a raw message object into a consistent structure.
+ */
+export function normalizeMessage(message: unknown): NormalizedMessage {
+  const m = message as Record<string, unknown>;
+  let role = typeof m.role === "string" ? m.role : "unknown";
+
+  // Detect tool result messages by presence of toolCallId or tool_call_id
+  if (typeof m.toolCallId === "string" || typeof m.tool_call_id === "string") {
+    role = "toolResult";
+  }
+
+  // Extract content
+  let content: MessageContentItem[] = [];
+
+  if (typeof m.content === "string") {
+    content = [{ type: "text", text: m.content }];
+  } else if (Array.isArray(m.content)) {
+    content = m.content.map((item: Record<string, unknown>) => ({
+      type: (item.type as MessageContentItem["type"]) || "text",
+      text: item.text as string | undefined,
+      name: item.name as string | undefined,
+      args: item.args || item.arguments,
+    }));
+  } else if (typeof m.text === "string") {
+    content = [{ type: "text", text: m.text }];
+  }
+
+  const timestamp = typeof m.timestamp === "number" ? m.timestamp : Date.now();
+  const id = typeof m.id === "string" ? m.id : undefined;
+
+  return { role, content, timestamp, id };
+}
+
+/**
+ * Normalize role for grouping purposes.
+ * Tool results should be grouped with assistant messages.
+ */
+export function normalizeRoleForGrouping(role: string): string {
+  const lower = role.toLowerCase();
+  // All tool-related roles should display as assistant
+  if (
+    lower === "toolresult" ||
+    lower === "tool_result" ||
+    lower === "tool" ||
+    lower === "function"
+  ) {
+    return "assistant";
+  }
+  return role;
+}
+
+/**
+ * Check if a message is a tool result message based on its role.
+ */
+export function isToolResultMessage(message: unknown): boolean {
+  const m = message as Record<string, unknown>;
+  const role = typeof m.role === "string" ? m.role.toLowerCase() : "";
+  return role === "toolresult" || role === "tool_result";
+}
--- a/ui/src/ui/chat/tool-helpers.test.ts
+++ b/ui/src/ui/chat/tool-helpers.test.ts
@@ -0,0 +1,141 @@
+import { describe, it, expect } from "vitest";
+import { formatToolOutputForSidebar, getTruncatedPreview } from "./tool-helpers";
+
+describe("tool-helpers", () => {
+  describe("formatToolOutputForSidebar", () => {
+    it("formats valid JSON object as code block", () => {
+      const input = '{"name":"test","value":123}';
+      const result = formatToolOutputForSidebar(input);
+
+      expect(result).toBe(`\`\`\`json
+{
+  "name": "test",
+  "value": 123
+}
+\`\`\``);
+    });
+
+    it("formats valid JSON array as code block", () => {
+      const input = '[1, 2, 3]';
+      const result = formatToolOutputForSidebar(input);
+
+      expect(result).toBe(`\`\`\`json
+[
+  1,
+  2,
+  3
+]
+\`\`\``);
+    });
+
+    it("handles nested JSON objects", () => {
+      const input = '{"outer":{"inner":"value"}}';
+      const result = formatToolOutputForSidebar(input);
+
+      expect(result).toContain("```json");
+      expect(result).toContain('"outer"');
+      expect(result).toContain('"inner"');
+    });
+
+    it("returns plain text for non-JSON content", () => {
+      const input = "This is plain text output";
+      const result = formatToolOutputForSidebar(input);
+
+      expect(result).toBe("This is plain text output");
+    });
+
+    it("returns as-is for invalid JSON starting with {", () => {
+      const input = "{not valid json";
+      const result = formatToolOutputForSidebar(input);
+
+      expect(result).toBe("{not valid json");
+    });
+
+    it("returns as-is for invalid JSON starting with [", () => {
+      const input = "[not valid json";
+      const result = formatToolOutputForSidebar(input);
+
+      expect(result).toBe("[not valid json");
+    });
+
+    it("trims whitespace before detecting JSON", () => {
+      const input = '   {"trimmed": true}   ';
+      const result = formatToolOutputForSidebar(input);
+
+      expect(result).toContain("```json");
+      expect(result).toContain('"trimmed"');
+    });
+
+    it("handles empty string", () => {
+      const result = formatToolOutputForSidebar("");
+      expect(result).toBe("");
+    });
+
+    it("handles whitespace-only string", () => {
+      const result = formatToolOutputForSidebar("   ");
+      expect(result).toBe("   ");
+    });
+  });
+
+  describe("getTruncatedPreview", () => {
+    it("returns short text unchanged", () => {
+      const input = "Short text";
+      const result = getTruncatedPreview(input);
+
+      expect(result).toBe("Short text");
+    });
+
+    it("truncates text longer than max chars", () => {
+      const input = "a".repeat(150);
+      const result = getTruncatedPreview(input);
+
+      expect(result.length).toBe(101); // 100 chars + ellipsis
+      expect(result.endsWith("…")).toBe(true);
+    });
+
+    it("truncates to max lines", () => {
+      const input = "Line 1\nLine 2\nLine 3\nLine 4\nLine 5";
+      const result = getTruncatedPreview(input);
+
+      // Should only show first 2 lines (PREVIEW_MAX_LINES = 2)
+      expect(result).toBe("Line 1\nLine 2…");
+    });
+
+    it("adds ellipsis when lines are truncated", () => {
+      const input = "Line 1\nLine 2\nLine 3";
+      const result = getTruncatedPreview(input);
+
+      expect(result.endsWith("…")).toBe(true);
+    });
+
+    it("does not add ellipsis when all lines fit", () => {
+      const input = "Line 1\nLine 2";
+      const result = getTruncatedPreview(input);
+
+      expect(result).toBe("Line 1\nLine 2");
+      expect(result.endsWith("…")).toBe(false);
+    });
+
+    it("handles single line within limits", () => {
+      const input = "Single line";
+      const result = getTruncatedPreview(input);
+
+      expect(result).toBe("Single line");
+    });
+
+    it("handles empty string", () => {
+      const result = getTruncatedPreview("");
+      expect(result).toBe("");
+    });
+
+    it("truncates by chars even within line limit", () => {
+      // Two lines but very long content
+      const longLine = "x".repeat(80);
+      const input = `${longLine}\n${longLine}`;
+      const result = getTruncatedPreview(input);
+
+      expect(result.length).toBe(101); // 100 + ellipsis
+      expect(result.endsWith("…")).toBe(true);
+    });
+  });
+});
--- a/ui/src/ui/chat/tool-helpers.ts
+++ b/ui/src/ui/chat/tool-helpers.ts
@@ -0,0 +1,36 @@
+/**
+ * Helper functions for tool card rendering.
+ */
+
+import { PREVIEW_MAX_CHARS, PREVIEW_MAX_LINES } from "./constants";
+
+/**
+ * Format tool output content for display in the sidebar.
+ * Detects JSON and wraps it in a code block with formatting.
+ */
+export function formatToolOutputForSidebar(text: string): string {
+  const trimmed = text.trim();
+  // Try to detect and format JSON
+  if (trimmed.startsWith("{") || trimmed.startsWith("[")) {
+    try {
+      const parsed = JSON.parse(trimmed);
+      return "```json\n" + JSON.stringify(parsed, null, 2) + "\n```";
+    } catch {
+      // Not valid JSON, return as-is
+    }
+  }
+  return text;
+}
+
+/**
+ * Get a truncated preview of tool output text.
+ * Truncates to first N lines or first N characters, whichever is shorter.
+ */
+export function getTruncatedPreview(text: string): string {
+  const lines = text.split("\n").slice(0, PREVIEW_MAX_LINES);
+  const preview = lines.join("\n");
+  if (preview.length > PREVIEW_MAX_CHARS) {
+    return preview.slice(0, PREVIEW_MAX_CHARS) + "…";
+  }
+  return lines.length < text.split("\n").length ? preview + "…" : preview;
+}
--- a/ui/src/ui/components/resizable-divider.ts
+++ b/ui/src/ui/components/resizable-divider.ts
@@ -0,0 +1,109 @@
+import { LitElement, html, css } from "lit";
+import { customElement, property } from "lit/decorators.js";
+
+/**
+ * A draggable divider for resizable split views.
+ * Dispatches 'resize' events with { splitRatio: number } detail.
+ */
+@customElement("resizable-divider")
+export class ResizableDivider extends LitElement {
+  @property({ type: Number }) splitRatio = 0.6;
+  @property({ type: Number }) minRatio = 0.4;
+  @property({ type: Number }) maxRatio = 0.7;
+
+  private isDragging = false;
+  private startX = 0;
+  private startRatio = 0;
+
+  static styles = css`
+    :host {
+      width: 4px;
+      cursor: col-resize;
+      background: var(--border, #333);
+      transition: background 150ms ease-out;
+      flex-shrink: 0;
+      position: relative;
+    }
+
+    :host::before {
+      content: "";
+      position: absolute;
+      top: 0;
+      left: -4px;
+      right: -4px;
+      bottom: 0;
+    }
+
+    :host(:hover) {
+      background: var(--accent, #007bff);
+    }
+
+    :host(.dragging) {
+      background: var(--accent, #007bff);
+    }
+  `;
+
+  render() {
+    return html``;
+  }
+
+  connectedCallback() {
+    super.connectedCallback();
+    this.addEventListener("mousedown", this.handleMouseDown);
+  }
+
+  disconnectedCallback() {
+    super.disconnectedCallback();
+    this.removeEventListener("mousedown", this.handleMouseDown);
+    document.removeEventListener("mousemove", this.handleMouseMove);
+    document.removeEventListener("mouseup", this.handleMouseUp);
+  }
+
+  private handleMouseDown = (e: MouseEvent) => {
+    this.isDragging = true;
+    this.startX = e.clientX;
+    this.startRatio = this.splitRatio;
+    this.classList.add("dragging");
+
+    document.addEventListener("mousemove", this.handleMouseMove);
+    document.addEventListener("mouseup", this.handleMouseUp);
+
+    e.preventDefault();
+  };
+
+  private handleMouseMove = (e: MouseEvent) => {
+    if (!this.isDragging) return;
+
+    const container = this.parentElement;
+    if (!container) return;
+
+    const containerWidth = container.getBoundingClientRect().width;
+    const deltaX = e.clientX - this.startX;
+    const deltaRatio = deltaX / containerWidth;
+
+    let newRatio = this.startRatio + deltaRatio;
+    newRatio = Math.max(this.minRatio, Math.min(this.maxRatio, newRatio));
+
+    this.dispatchEvent(
+      new CustomEvent("resize", {
+        detail: { splitRatio: newRatio },
+        bubbles: true,
+        composed: true,
+      })
+    );
+  };
+
+  private handleMouseUp = () => {
+    this.isDragging = false;
+    this.classList.remove("dragging");
+
+    document.removeEventListener("mousemove", this.handleMouseMove);
+    document.removeEventListener("mouseup", this.handleMouseUp);
+  };
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    "resizable-divider": ResizableDivider;
+  }
+}
--- a/ui/src/ui/focus-mode.browser.test.ts
+++ b/ui/src/ui/focus-mode.browser.test.ts
@@ -65,4 +65,3 @@ describe("chat focus mode", () => {
    expect(shell?.classList.contains("shell--chat-focus")).toBe(true);
  });
 });
-
--- a/ui/src/ui/navigation.test.ts
+++ b/ui/src/ui/navigation.test.ts
@@ -0,0 +1,190 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  TAB_GROUPS,
+  iconForTab,
+  inferBasePathFromPathname,
+  normalizeBasePath,
+  normalizePath,
+  pathForTab,
+  subtitleForTab,
+  tabFromPath,
+  titleForTab,
+  type Tab,
+} from "./navigation";
+
+/** All valid tab identifiers derived from TAB_GROUPS */
+const ALL_TABS: Tab[] = TAB_GROUPS.flatMap((group) => group.tabs) as Tab[];
+
+describe("iconForTab", () => {
+  it("returns a non-empty string for every tab", () => {
+    for (const tab of ALL_TABS) {
+      const icon = iconForTab(tab);
+      expect(icon).toBeTruthy();
+      expect(typeof icon).toBe("string");
+      expect(icon.length).toBeGreaterThan(0);
+    }
+  });
+
+  it("returns stable icons for known tabs", () => {
+    expect(iconForTab("chat")).toBe("💬");
+    expect(iconForTab("overview")).toBe("📊");
+    expect(iconForTab("connections")).toBe("🔗");
+    expect(iconForTab("instances")).toBe("📡");
+    expect(iconForTab("sessions")).toBe("📄");
+    expect(iconForTab("cron")).toBe("⏰");
+    expect(iconForTab("skills")).toBe("⚡️");
+    expect(iconForTab("nodes")).toBe("🖥️");
+    expect(iconForTab("config")).toBe("⚙️");
+    expect(iconForTab("debug")).toBe("🐞");
+    expect(iconForTab("logs")).toBe("🧾");
+  });
+
+  it("returns a fallback icon for unknown tab", () => {
+    // TypeScript won't allow this normally, but runtime could receive unexpected values
+    const unknownTab = "unknown" as Tab;
+    expect(iconForTab(unknownTab)).toBe("📁");
+  });
+});
+
+describe("titleForTab", () => {
+  it("returns a non-empty string for every tab", () => {
+    for (const tab of ALL_TABS) {
+      const title = titleForTab(tab);
+      expect(title).toBeTruthy();
+      expect(typeof title).toBe("string");
+    }
+  });
+
+  it("returns expected titles", () => {
+    expect(titleForTab("chat")).toBe("Chat");
+    expect(titleForTab("overview")).toBe("Overview");
+    expect(titleForTab("cron")).toBe("Cron Jobs");
+  });
+});
+
+describe("subtitleForTab", () => {
+  it("returns a string for every tab", () => {
+    for (const tab of ALL_TABS) {
+      const subtitle = subtitleForTab(tab);
+      expect(typeof subtitle).toBe("string");
+    }
+  });
+
+  it("returns descriptive subtitles", () => {
+    expect(subtitleForTab("chat")).toContain("chat session");
+    expect(subtitleForTab("config")).toContain("clawdbot.json");
+  });
+});
+
+describe("normalizeBasePath", () => {
+  it("returns empty string for falsy input", () => {
+    expect(normalizeBasePath("")).toBe("");
+  });
+
+  it("adds leading slash if missing", () => {
+    expect(normalizeBasePath("ui")).toBe("/ui");
+  });
+
+  it("removes trailing slash", () => {
+    expect(normalizeBasePath("/ui/")).toBe("/ui");
+  });
+
+  it("returns empty string for root path", () => {
+    expect(normalizeBasePath("/")).toBe("");
+  });
+
+  it("handles nested paths", () => {
+    expect(normalizeBasePath("/apps/clawdbot")).toBe("/apps/clawdbot");
+  });
+});
+
+describe("normalizePath", () => {
+  it("returns / for falsy input", () => {
+    expect(normalizePath("")).toBe("/");
+  });
+
+  it("adds leading slash if missing", () => {
+    expect(normalizePath("chat")).toBe("/chat");
+  });
+
+  it("removes trailing slash except for root", () => {
+    expect(normalizePath("/chat/")).toBe("/chat");
+    expect(normalizePath("/")).toBe("/");
+  });
+});
+
+describe("pathForTab", () => {
+  it("returns correct path without base", () => {
+    expect(pathForTab("chat")).toBe("/chat");
+    expect(pathForTab("overview")).toBe("/overview");
+  });
+
+  it("prepends base path", () => {
+    expect(pathForTab("chat", "/ui")).toBe("/ui/chat");
+    expect(pathForTab("sessions", "/apps/clawdbot")).toBe("/apps/clawdbot/sessions");
+  });
+});
+
+describe("tabFromPath", () => {
+  it("returns tab for valid path", () => {
+    expect(tabFromPath("/chat")).toBe("chat");
+    expect(tabFromPath("/overview")).toBe("overview");
+    expect(tabFromPath("/sessions")).toBe("sessions");
+  });
+
+  it("returns chat for root path", () => {
+    expect(tabFromPath("/")).toBe("chat");
+  });
+
+  it("handles base paths", () => {
+    expect(tabFromPath("/ui/chat", "/ui")).toBe("chat");
+    expect(tabFromPath("/apps/clawdbot/sessions", "/apps/clawdbot")).toBe("sessions");
+  });
+
+  it("returns null for unknown path", () => {
+    expect(tabFromPath("/unknown")).toBeNull();
+  });
+
+  it("is case-insensitive", () => {
+    expect(tabFromPath("/CHAT")).toBe("chat");
+    expect(tabFromPath("/Overview")).toBe("overview");
+  });
+});
+
+describe("inferBasePathFromPathname", () => {
+  it("returns empty string for root", () => {
+    expect(inferBasePathFromPathname("/")).toBe("");
+  });
+
+  it("returns empty string for direct tab path", () => {
+    expect(inferBasePathFromPathname("/chat")).toBe("");
+    expect(inferBasePathFromPathname("/overview")).toBe("");
+  });
+
+  it("infers base path from nested paths", () => {
+    expect(inferBasePathFromPathname("/ui/chat")).toBe("/ui");
+    expect(inferBasePathFromPathname("/apps/clawdbot/sessions")).toBe("/apps/clawdbot");
+  });
+
+  it("handles index.html suffix", () => {
+    expect(inferBasePathFromPathname("/index.html")).toBe("");
+    expect(inferBasePathFromPathname("/ui/index.html")).toBe("/ui");
+  });
+});
+
+describe("TAB_GROUPS", () => {
+  it("contains all expected groups", () => {
+    const labels = TAB_GROUPS.map((g) => g.label);
+    expect(labels).toContain("Chat");
+    expect(labels).toContain("Control");
+    expect(labels).toContain("Agent");
+    expect(labels).toContain("Settings");
+  });
+
+  it("all tabs are unique", () => {
+    const allTabs = TAB_GROUPS.flatMap((g) => g.tabs);
+    const uniqueTabs = new Set(allTabs);
+    expect(uniqueTabs.size).toBe(allTabs.length);
+  });
+});
--- a/ui/src/ui/navigation.ts
+++ b/ui/src/ui/navigation.ts
@@ -98,6 +98,35 @@ export function inferBasePathFromPathname(pathname: string): string {
  return `/${segments.join("/")}`;
 }

+export function iconForTab(tab: Tab): string {
+  switch (tab) {
+    case "chat":
+      return "💬";
+    case "overview":
+      return "📊";
+    case "connections":
+      return "🔗";
+    case "instances":
+      return "📡";
+    case "sessions":
+      return "📄";
+    case "cron":
+      return "⏰";
+    case "skills":
+      return "⚡️";
+    case "nodes":
+      return "🖥️";
+    case "config":
+      return "⚙️";
+    case "debug":
+      return "🐞";
+    case "logs":
+      return "🧾";
+    default:
+      return "📁";
+  }
+}
+
 export function titleForTab(tab: Tab) {
  switch (tab) {
    case "overview":
--- a/ui/src/ui/storage.ts
+++ b/ui/src/ui/storage.ts
@@ -9,6 +9,10 @@ export type UiSettings = {
  lastActiveSessionKey: string;
  theme: ThemeMode;
  chatFocusMode: boolean;
+  splitRatio: number; // Sidebar split ratio (0.4 to 0.7, default 0.6)
+  useNewChatLayout: boolean; // Slack-style grouped messages layout
+  navCollapsed: boolean; // Collapsible sidebar state
+  navGroupsCollapsed: Record<string, boolean>; // Which nav groups are collapsed
 };

 export function loadSettings(): UiSettings {
@@ -24,6 +28,10 @@ export function loadSettings(): UiSettings {
    lastActiveSessionKey: "main",
    theme: "system",
    chatFocusMode: false,
+    splitRatio: 0.6,
+    useNewChatLayout: true, // Enabled by default
+    navCollapsed: false,
+    navGroupsCollapsed: {},
  };

  try {
@@ -57,6 +65,25 @@ export function loadSettings(): UiSettings {
        typeof parsed.chatFocusMode === "boolean"
          ? parsed.chatFocusMode
          : defaults.chatFocusMode,
+      splitRatio:
+        typeof parsed.splitRatio === "number" &&
+        parsed.splitRatio >= 0.4 &&
+        parsed.splitRatio <= 0.7
+          ? parsed.splitRatio
+          : defaults.splitRatio,
+      useNewChatLayout:
+        typeof parsed.useNewChatLayout === "boolean"
+          ? parsed.useNewChatLayout
+          : defaults.useNewChatLayout,
+      navCollapsed:
+        typeof parsed.navCollapsed === "boolean"
+          ? parsed.navCollapsed
+          : defaults.navCollapsed,
+      navGroupsCollapsed:
+        typeof parsed.navGroupsCollapsed === "object" &&
+        parsed.navGroupsCollapsed !== null
+          ? parsed.navGroupsCollapsed
+          : defaults.navGroupsCollapsed,
    };
  } catch {
    return defaults;
--- a/ui/src/ui/types/chat-types.ts
+++ b/ui/src/ui/types/chat-types.ts
@@ -0,0 +1,43 @@
+/**
+ * Chat message types for the UI layer.
+ */
+
+/** Union type for items in the chat thread */
+export type ChatItem =
+  | { kind: "message"; key: string; message: unknown }
+  | { kind: "stream"; key: string; text: string; startedAt: number }
+  | { kind: "reading-indicator"; key: string };
+
+/** A group of consecutive messages from the same role (Slack-style layout) */
+export type MessageGroup = {
+  kind: "group";
+  key: string;
+  role: string;
+  messages: Array<{ message: unknown; key: string }>;
+  timestamp: number;
+  isStreaming: boolean;
+};
+
+/** Content item types in a normalized message */
+export type MessageContentItem = {
+  type: "text" | "tool_call" | "tool_result";
+  text?: string;
+  name?: string;
+  args?: unknown;
+};
+
+/** Normalized message structure for rendering */
+export type NormalizedMessage = {
+  role: string;
+  content: MessageContentItem[];
+  timestamp: number;
+  id?: string;
+};
+
+/** Tool card representation for tool calls and results */
+export type ToolCard = {
+  kind: "call" | "result";
+  name: string;
+  args?: unknown;
+  text?: string;
+};
--- a/ui/src/ui/views/chat.ts
+++ b/ui/src/ui/views/chat.ts
@@ -7,6 +7,19 @@ import { toSanitizedMarkdownHtml } from "../markdown";
 import { formatToolDetail, resolveToolDisplay } from "../tool-display";
 import type { SessionsListResult } from "../types";
 import type { ChatQueueItem } from "../ui-types";
+import type { ChatItem, MessageGroup, ToolCard } from "../types/chat-types";
+import { TOOL_INLINE_THRESHOLD } from "../chat/constants";
+import {
+  formatToolOutputForSidebar,
+  getTruncatedPreview,
+} from "../chat/tool-helpers";
+import {
+  normalizeMessage,
+  normalizeRoleForGrouping,
+  isToolResultMessage,
+} from "../chat/message-normalizer";
+import { renderMarkdownSidebar } from "./markdown-sidebar";
+import "../components/resizable-divider";

 export type ChatProps = {
  sessionKey: string;
@@ -25,97 +38,140 @@ export type ChatProps = {
  disabledReason: string | null;
  error: string | null;
  sessions: SessionsListResult | null;
+  // Legacy tool output expand/collapse (used when useNewChatLayout is false)
  isToolOutputExpanded: (id: string) => boolean;
  onToolOutputToggle: (id: string, expanded: boolean) => void;
+  // Focus mode
+  focusMode: boolean;
+  // Feature flag for new Slack-style layout with sidebar
+  useNewChatLayout?: boolean;
+  // Sidebar state (used when useNewChatLayout is true)
+  sidebarOpen?: boolean;
+  sidebarContent?: string | null;
+  sidebarError?: string | null;
+  splitRatio?: number;
+  // Event handlers
  onRefresh: () => void;
+  onToggleFocusMode: () => void;
+  onToggleLayout?: () => void;
  onDraftChange: (next: string) => void;
  onSend: () => void;
  onQueueRemove: (id: string) => void;
  onNewSession: () => void;
+  onOpenSidebar?: (content: string) => void;
+  onCloseSidebar?: () => void;
+  onSplitRatioChange?: (ratio: number) => void;
 };

 export function renderChat(props: ChatProps) {
  const canCompose = props.connected;
  const isBusy = props.sending || Boolean(props.stream);
-  const sessionOptions = resolveSessionOptions(props.sessionKey, props.sessions);
  const activeSession = props.sessions?.sessions?.find(
    (row) => row.key === props.sessionKey,
  );
  const reasoningLevel = activeSession?.reasoningLevel ?? "off";
  const showReasoning = reasoningLevel !== "off";
+
  const composePlaceholder = props.connected
    ? "Message (↩ to send, Shift+↩ for line breaks)"
    : "Connect to the gateway to start chatting…";

+  const splitRatio = props.splitRatio ?? 0.6;
+  const sidebarOpen = Boolean(props.sidebarOpen && props.onCloseSidebar);
+  const useNewLayout = props.useNewChatLayout ?? false;
+
  return html`
    <section class="card chat">
-      <div class="chat-header">
-        <div class="chat-header__left">
-          <label class="field chat-session">
-            <span>Session Key</span>
-            <select
-              .value=${props.sessionKey}
-              ?disabled=${!props.connected}
-              @change=${(e: Event) =>
-                props.onSessionKeyChange((e.target as HTMLSelectElement).value)}
+      ${props.disabledReason
+        ? html`<div class="callout">${props.disabledReason}</div>`
+        : nothing}
+
+      ${props.error
+        ? html`<div class="callout danger">${props.error}</div>`
+        : nothing}
+
+      ${props.focusMode
+        ? html`
+            <button
+              class="chat-focus-exit"
+              type="button"
+              @click=${props.onToggleFocusMode}
+              aria-label="Exit focus mode"
+              title="Exit focus mode"
            >
-              ${sessionOptions.map(
-                (entry) =>
-                  html`<option value=${entry.key}>
-                    ${entry.displayName ?? entry.key}
-                  </option>`
-              )}
-            </select>
-          </label>
-          <button
-            class="btn"
-            ?disabled=${props.loading || !props.connected}
-            @click=${props.onRefresh}
-          >
-            ${props.loading ? "Loading…" : "Refresh"}
-          </button>
+              ✕
+            </button>
+          `
+        : nothing}
+
+      <div
+        class="chat-split-container ${sidebarOpen ? "chat-split-container--open" : ""}"
+      >
+        <div
+          class="chat-main"
+          style="flex: ${sidebarOpen ? `0 0 ${splitRatio * 100}%` : "1 1 100%"}"
+        >
+          <div class="chat-thread" role="log" aria-live="polite">
+            ${props.loading
+              ? html`<div class="muted">Loading chat…</div>`
+              : nothing}
+            ${repeat(buildChatItems(props), (item) => item.key, (item) => {
+              if (item.kind === "reading-indicator") {
+                return useNewLayout
+                  ? renderReadingIndicatorGroup()
+                  : renderReadingIndicator();
+              }
+
+              if (item.kind === "stream") {
+                return useNewLayout
+                  ? renderStreamingGroup(
+                      item.text,
+                      item.startedAt,
+                      props.onOpenSidebar,
+                    )
+                  : renderMessage(
+                      {
+                        role: "assistant",
+                        content: [{ type: "text", text: item.text }],
+                        timestamp: item.startedAt,
+                      },
+                      props,
+                      { streaming: true, showReasoning },
+                    );
+              }
+
+              if (item.kind === "group") {
+                return renderMessageGroup(item, {
+                  onOpenSidebar: props.onOpenSidebar,
+                  showReasoning,
+                });
+              }
+
+              return renderMessage(item.message, props, { showReasoning });
+            })}
+          </div>
        </div>
-        <div class="chat-header__right">
-          <div class="muted">Thinking: ${props.thinkingLevel ?? "inherit"}</div>
-          <div class="muted">Reasoning: ${reasoningLevel}</div>
-        </div>
-      </div>

-      ${
-        props.disabledReason
-          ? html`<div class="callout" style="margin-top: 12px;">
-            ${props.disabledReason}
-          </div>`
-          : nothing
-      }
-
-      ${
-        props.error
-          ? html`<div class="callout danger" style="margin-top: 12px;">${props.error}</div>`
-          : nothing
-      }
-
-      <div class="chat-thread" role="log" aria-live="polite">
-        ${props.loading ? html`<div class="muted">Loading chat…</div>` : nothing}
-        ${repeat(
-          buildChatItems(props),
-          (item) => item.key,
-          (item) => {
-            if (item.kind === "reading-indicator") return renderReadingIndicator();
-            if (item.kind === "stream") {
-              return renderMessage(
-                {
-                  role: "assistant",
-                  content: [{ type: "text", text: item.text }],
-                  timestamp: item.startedAt,
-                },
-                props,
-                { streaming: true }
-              );
-            }
-            return renderMessage(item.message, props, { showReasoning });
-          }
-        )}
+        ${useNewLayout && sidebarOpen
+          ? html`
+              <resizable-divider
+                .splitRatio=${splitRatio}
+                @resize=${(e: CustomEvent) =>
+                  props.onSplitRatioChange?.(e.detail.splitRatio)}
+              ></resizable-divider>
+              <div class="chat-sidebar">
+                ${renderMarkdownSidebar({
+                  content: props.sidebarContent ?? null,
+                  error: props.sidebarError ?? null,
+                  onClose: props.onCloseSidebar!,
+                  onViewRawText: () => {
+                    if (!props.sidebarContent || !props.onOpenSidebar) return;
+                    props.onOpenSidebar(`\`\`\`\n${props.sidebarContent}\n\`\`\``);
+                  },
+                })}
+              </div>
+            `
+          : nothing}
      </div>

      ${props.queue.length
@@ -157,11 +213,12 @@ export function renderChat(props: ChatProps) {
              e.preventDefault();
              if (canCompose) props.onSend();
            }}
-            @input=${(e: Event) => props.onDraftChange((e.target as HTMLTextAreaElement).value)}
+            @input=${(e: Event) =>
+              props.onDraftChange((e.target as HTMLTextAreaElement).value)}
            placeholder=${composePlaceholder}
          ></textarea>
        </label>
-        <div class="row chat-compose__actions">
+        <div class="chat-compose__actions">
          <button
            class="btn"
            ?disabled=${!props.connected || props.sending}
@@ -182,14 +239,46 @@ export function renderChat(props: ChatProps) {
  `;
 }

-type ChatItem =
-  | { kind: "message"; key: string; message: unknown }
-  | { kind: "stream"; key: string; text: string; startedAt: number }
-  | { kind: "reading-indicator"; key: string };
-
 const CHAT_HISTORY_RENDER_LIMIT = 200;

-function buildChatItems(props: ChatProps): ChatItem[] {
+function groupMessages(items: ChatItem[]): Array<ChatItem | MessageGroup> {
+  const result: Array<ChatItem | MessageGroup> = [];
+  let currentGroup: MessageGroup | null = null;
+
+  for (const item of items) {
+    if (item.kind !== "message") {
+      if (currentGroup) {
+        result.push(currentGroup);
+        currentGroup = null;
+      }
+      result.push(item);
+      continue;
+    }
+
+    const normalized = normalizeMessage(item.message);
+    const role = normalizeRoleForGrouping(normalized.role);
+    const timestamp = normalized.timestamp || Date.now();
+
+    if (!currentGroup || currentGroup.role !== role) {
+      if (currentGroup) result.push(currentGroup);
+      currentGroup = {
+        kind: "group",
+        key: `group:${role}:${item.key}`,
+        role,
+        messages: [{ message: item.message, key: item.key }],
+        timestamp,
+        isStreaming: false,
+      };
+    } else {
+      currentGroup.messages.push({ message: item.message, key: item.key });
+    }
+  }
+
+  if (currentGroup) result.push(currentGroup);
+  return result;
+}
+
+function buildChatItems(props: ChatProps): Array<ChatItem | MessageGroup> {
  const items: ChatItem[] = [];
  const history = Array.isArray(props.messages) ? props.messages : [];
  const tools = Array.isArray(props.toolMessages) ? props.toolMessages : [];
@@ -234,6 +323,7 @@ function buildChatItems(props: ChatProps): ChatItem[] {
    }
  }

+  if (props.useNewChatLayout) return groupMessages(items);
  return items;
 }

@@ -247,7 +337,8 @@ function messageKey(message: unknown, index: number): string {
  if (messageId) return `msg:${messageId}`;
  const timestamp = typeof m.timestamp === "number" ? m.timestamp : null;
  const role = typeof m.role === "string" ? m.role : "unknown";
-  const fingerprint = extractText(message) ?? (typeof m.content === "string" ? m.content : null);
+  const fingerprint =
+    extractText(message) ?? (typeof m.content === "string" ? m.content : null);
  const seed = fingerprint ?? safeJson(message) ?? String(index);
  const hash = fnv1a(seed);
  return timestamp ? `msg:${role}:${timestamp}:${hash}` : `msg:${role}:${hash}`;
@@ -270,51 +361,6 @@ function fnv1a(input: string): string {
  return (hash >>> 0).toString(36);
 }

-type SessionOption = {
-  key: string;
-  updatedAt?: number | null;
-  displayName?: string;
-};
-
-function resolveSessionOptions(currentKey: string, sessions: SessionsListResult | null) {
-  const now = Date.now();
-  const cutoff = now - 24 * 60 * 60 * 1000;
-  const entries = Array.isArray(sessions?.sessions) ? (sessions?.sessions ?? []) : [];
-  const sorted = [...entries].sort((a, b) => (b.updatedAt ?? 0) - (a.updatedAt ?? 0));
-  const recent: SessionOption[] = [];
-  const seen = new Set<string>();
-  for (const entry of sorted) {
-    if (seen.has(entry.key)) continue;
-    seen.add(entry.key);
-    if ((entry.updatedAt ?? 0) < cutoff) continue;
-    recent.push(entry);
-  }
-
-  const result: SessionOption[] = [];
-  const included = new Set<string>();
-  const mainKey = "main";
-  const mainEntry = sorted.find((entry) => entry.key === mainKey);
-  if (mainEntry) {
-    result.push(mainEntry);
-    included.add(mainKey);
-  } else if (currentKey === mainKey) {
-    result.push({ key: mainKey, updatedAt: null });
-    included.add(mainKey);
-  }
-
-  for (const entry of recent) {
-    if (included.has(entry.key)) continue;
-    result.push(entry);
-    included.add(entry.key);
-  }
-
-  if (!included.has(currentKey)) {
-    result.push({ key: currentKey, updatedAt: null });
-  }
-
-  return result;
-}
-
 function renderReadingIndicator() {
  return html`
    <div class="chat-line assistant">
@@ -329,21 +375,37 @@ function renderReadingIndicator() {
  `;
 }

+function renderReadingIndicatorGroup() {
+  return html`
+    <div class="chat-group assistant">
+      ${renderAvatar("assistant")}
+      <div class="chat-group-messages">
+        <div class="chat-bubble chat-reading-indicator" aria-hidden="true">
+          <span class="chat-reading-indicator__dots">
+            <span></span><span></span><span></span>
+          </span>
+        </div>
+      </div>
+    </div>
+  `;
+}
+
 function renderMessage(
  message: unknown,
  props?: Pick<ChatProps, "isToolOutputExpanded" | "onToolOutputToggle">,
-  opts?: { streaming?: boolean; showReasoning?: boolean }
+  opts?: { streaming?: boolean; showReasoning?: boolean },
 ) {
  const m = message as Record<string, unknown>;
  const role = typeof m.role === "string" ? m.role : "unknown";
  const toolCards = extractToolCards(message);
  const hasToolCards = toolCards.length > 0;
-  const isToolResult = isToolResultMessage(message);
+  const isToolResult =
+    isToolResultMessage(message) ||
+    typeof m.toolCallId === "string" ||
+    typeof m.tool_call_id === "string";
  const extractedText = extractText(message);
  const extractedThinking =
-    opts?.showReasoning && role === "assistant"
-      ? extractThinking(message)
-      : null;
+    opts?.showReasoning && role === "assistant" ? extractThinking(message) : null;
  const contentText = typeof m.content === "string" ? m.content : null;
  const fallback = hasToolCards ? null : JSON.stringify(message, null, 2);

@@ -355,6 +417,7 @@ function renderMessage(
        : !isToolResult && fallback
          ? { kind: "json" as const, value: fallback }
          : null;
+
  const markdownBase =
    display?.kind === "json"
      ? ["```json", display.value, "```"].join("\n")
@@ -367,31 +430,43 @@ function renderMessage(

  const timestamp =
    typeof m.timestamp === "number" ? new Date(m.timestamp).toLocaleTimeString() : "";
-  const klass = role === "assistant" ? "assistant" : role === "user" ? "user" : "other";
-  const who = role === "assistant" ? "Assistant" : role === "user" ? "You" : role;
+
+  const normalizedRole = normalizeRoleForGrouping(role);
+  const klass =
+    normalizedRole === "assistant"
+      ? "assistant"
+      : normalizedRole === "user"
+        ? "user"
+        : "other";
+  const who =
+    normalizedRole === "assistant"
+      ? "Assistant"
+      : normalizedRole === "user"
+        ? "You"
+        : normalizedRole;
+
  const toolCallId = typeof m.toolCallId === "string" ? m.toolCallId : "";
  const toolCardBase =
    toolCallId ||
    (typeof m.id === "string" ? m.id : "") ||
    (typeof m.messageId === "string" ? m.messageId : "") ||
    (typeof m.timestamp === "number" ? String(m.timestamp) : "tool-card");
+
  return html`
    <div class="chat-line ${klass}">
      <div class="chat-msg">
        <div class="chat-bubble ${opts?.streaming ? "streaming" : ""}">
-          ${
-            markdown
-              ? html`<div class="chat-text">${unsafeHTML(toSanitizedMarkdownHtml(markdown))}</div>`
-              : nothing
-          }
+          ${markdown
+            ? html`<div class="chat-text">${unsafeHTML(toSanitizedMarkdownHtml(markdown))}</div>`
+            : nothing}
          ${toolCards.map((card, index) =>
-            renderToolCard(card, {
+            renderToolCardLegacy(card, {
              id: `${toolCardBase}:${index}`,
              expanded: props?.isToolOutputExpanded
                ? props.isToolOutputExpanded(`${toolCardBase}:${index}`)
                : false,
              onToggle: props?.onToolOutputToggle,
-            })
+            }),
          )}
        </div>
        <div class="chat-stamp mono">
@@ -446,7 +521,11 @@ function extractThinking(message: unknown): string | null {
  // Back-compat: older logs may still have <think> tags inside text blocks.
  const rawText = extractRawText(message);
  if (!rawText) return null;
-  const matches = [...rawText.matchAll(/<\s*think(?:ing)?\s*>([\s\S]*?)<\s*\/\s*think(?:ing)?\s*>/gi)];
+  const matches = [
+    ...rawText.matchAll(
+      /<\s*think(?:ing)?\s*>([\s\S]*?)<\s*\/\s*think(?:ing)?\s*>/gi,
+    ),
+  ];
  const extracted = matches
    .map((m) => (m[1] ?? "").trim())
    .filter(Boolean);
@@ -482,13 +561,6 @@ function formatReasoningMarkdown(text: string): string {
  return lines.length ? ["_Reasoning:_", ...lines].join("\n") : "";
 }

-type ToolCard = {
-  kind: "call" | "result";
-  name: string;
-  args?: unknown;
-  text?: string;
-};
-
 function extractToolCards(message: unknown): ToolCard[] {
  const m = message as Record<string, unknown>;
  const content = normalizeContent(m.content);
@@ -516,7 +588,10 @@ function extractToolCards(message: unknown): ToolCard[] {
    cards.push({ kind: "result", name, text });
  }

-  if (isToolResultMessage(message) && !cards.some((card) => card.kind === "result")) {
+  if (
+    isToolResultMessage(message) &&
+    !cards.some((card) => card.kind === "result")
+  ) {
    const name =
      (typeof m.toolName === "string" && m.toolName) ||
      (typeof m.tool_name === "string" && m.tool_name) ||
@@ -528,13 +603,13 @@ function extractToolCards(message: unknown): ToolCard[] {
  return cards;
 }

-function renderToolCard(
+function renderToolCardLegacy(
  card: ToolCard,
  opts?: {
    id: string;
    expanded: boolean;
    onToggle?: (id: string, expanded: boolean) => void;
-  }
+  },
 ) {
  const display = resolveToolDisplay({ name: card.name, args: card.args });
  const detail = formatToolDetail(display);
@@ -543,11 +618,18 @@ function renderToolCard(
  const id = opts?.id ?? `${card.name}-${Math.random()}`;
  return html`
    <div class="chat-tool-card">
-      <div class="chat-tool-card__title">${display.emoji} ${display.label}</div>
-      ${detail ? html`<div class="chat-tool-card__detail">${detail}</div>` : nothing}
-      ${
-        hasOutput
-          ? html`
+      <div class="chat-tool-card__header">
+        <div class="chat-tool-card__title">
+          <span class="chat-tool-card__icon">${display.emoji}</span>
+          <span>${display.label}</span>
+        </div>
+        ${!hasOutput ? html`<span class="chat-tool-card__status">✓</span>` : nothing}
+      </div>
+      ${detail
+        ? html`<div class="chat-tool-card__detail">${detail}</div>`
+        : nothing}
+      ${hasOutput
+        ? html`
            <details
              class="chat-tool-card__details"
              ?open=${expanded}
@@ -563,17 +645,219 @@ function renderToolCard(
                  (${card.text?.length ?? 0} chars)
                </span>
              </summary>
-              ${
-                expanded
-                  ? html`<div class="chat-tool-card__output chat-text">
+              ${expanded
+                ? html`<div class="chat-tool-card__output chat-text">
                    ${unsafeHTML(toSanitizedMarkdownHtml(card.text ?? ""))}
                  </div>`
-                  : nothing
-              }
+                : nothing}
            </details>
          `
-          : nothing
+        : nothing}
+    </div>
+  `;
+}
+
+function renderToolCardSidebar(
+  card: ToolCard,
+  onOpenSidebar?: (content: string) => void,
+) {
+  const display = resolveToolDisplay({ name: card.name, args: card.args });
+  const detail = formatToolDetail(display);
+  const hasText = Boolean(card.text?.trim());
+
+  const canClick = Boolean(onOpenSidebar);
+  const handleClick = canClick
+    ? () => {
+        if (hasText) {
+          onOpenSidebar!(formatToolOutputForSidebar(card.text!));
+          return;
+        }
+        const info = `## ${display.label}\n\n${
+          detail ? `**Command:** \`${detail}\`\n\n` : ""
+        }*No output — tool completed successfully.*`;
+        onOpenSidebar!(info);
      }
+    : undefined;
+
+  const isShort = hasText && (card.text?.length ?? 0) <= TOOL_INLINE_THRESHOLD;
+  const showCollapsed = hasText && !isShort;
+  const showInline = hasText && isShort;
+  const isEmpty = !hasText;
+
+  return html`
+    <div
+      class="chat-tool-card ${canClick ? "chat-tool-card--clickable" : ""}"
+      @click=${handleClick}
+      role=${canClick ? "button" : nothing}
+      tabindex=${canClick ? "0" : nothing}
+      @keydown=${canClick
+        ? (e: KeyboardEvent) => {
+            if (e.key !== "Enter" && e.key !== " ") return;
+            e.preventDefault();
+            handleClick?.();
+          }
+        : nothing}
+    >
+      <div class="chat-tool-card__header">
+        <div class="chat-tool-card__title">
+          <span class="chat-tool-card__icon">${display.emoji}</span>
+          <span>${display.label}</span>
+        </div>
+        ${canClick
+          ? html`<span class="chat-tool-card__action">${hasText ? "View ›" : "›"}</span>`
+          : nothing}
+        ${isEmpty && !canClick ? html`<span class="chat-tool-card__status">✓</span>` : nothing}
+      </div>
+      ${detail
+        ? html`<div class="chat-tool-card__detail">${detail}</div>`
+        : nothing}
+      ${isEmpty
+        ? html`<div class="chat-tool-card__status-text muted">Completed</div>`
+        : nothing}
+      ${showCollapsed
+        ? html`<div class="chat-tool-card__preview mono">${getTruncatedPreview(card.text!)}</div>`
+        : nothing}
+      ${showInline
+        ? html`<div class="chat-tool-card__inline mono">${card.text}</div>`
+        : nothing}
+    </div>
+  `;
+}
+
+function renderAvatar(role: string) {
+  const normalized = normalizeRoleForGrouping(role);
+  const initial = normalized === "user" ? "U" : normalized === "assistant" ? "A" : "?";
+  const className = normalized === "user" ? "user" : normalized === "assistant" ? "assistant" : "other";
+  return html`<div class="chat-avatar ${className}">${initial}</div>`;
+}
+
+function renderStreamingGroup(
+  text: string,
+  startedAt: number,
+  onOpenSidebar?: (content: string) => void,
+) {
+  const timestamp = new Date(startedAt).toLocaleTimeString([], {
+    hour: "numeric",
+    minute: "2-digit",
+  });
+
+  return html`
+    <div class="chat-group assistant">
+      ${renderAvatar("assistant")}
+      <div class="chat-group-messages">
+        ${renderGroupedMessage(
+          {
+            role: "assistant",
+            content: [{ type: "text", text }],
+            timestamp: startedAt,
+          },
+          { isStreaming: true, showReasoning: false },
+          onOpenSidebar,
+        )}
+        <div class="chat-group-footer">
+          <span class="chat-sender-name">Assistant</span>
+          <span class="chat-group-timestamp">${timestamp}</span>
+        </div>
+      </div>
+    </div>
+  `;
+}
+
+function renderMessageGroup(
+  group: MessageGroup,
+  opts: { onOpenSidebar?: (content: string) => void; showReasoning: boolean },
+) {
+  const normalizedRole = normalizeRoleForGrouping(group.role);
+  const who =
+    normalizedRole === "user"
+      ? "You"
+      : normalizedRole === "assistant"
+        ? "Assistant"
+        : normalizedRole;
+  const roleClass =
+    normalizedRole === "user"
+      ? "user"
+      : normalizedRole === "assistant"
+        ? "assistant"
+        : "other";
+  const timestamp = new Date(group.timestamp).toLocaleTimeString([], {
+    hour: "numeric",
+    minute: "2-digit",
+  });
+
+  return html`
+    <div class="chat-group ${roleClass}">
+      ${renderAvatar(group.role)}
+      <div class="chat-group-messages">
+        ${group.messages.map((item, index) =>
+          renderGroupedMessage(
+            item.message,
+            {
+              isStreaming:
+                group.isStreaming && index === group.messages.length - 1,
+              showReasoning: opts.showReasoning,
+            },
+            opts.onOpenSidebar,
+          ),
+        )}
+        <div class="chat-group-footer">
+          <span class="chat-sender-name">${who}</span>
+          <span class="chat-group-timestamp">${timestamp}</span>
+        </div>
+      </div>
+    </div>
+  `;
+}
+
+function renderGroupedMessage(
+  message: unknown,
+  opts: { isStreaming: boolean; showReasoning: boolean },
+  onOpenSidebar?: (content: string) => void,
+) {
+  const m = message as Record<string, unknown>;
+  const role = typeof m.role === "string" ? m.role : "unknown";
+  const isToolResult =
+    isToolResultMessage(message) ||
+    role.toLowerCase() === "toolresult" ||
+    role.toLowerCase() === "tool_result" ||
+    typeof m.toolCallId === "string" ||
+    typeof m.tool_call_id === "string";
+
+  const toolCards = extractToolCards(message);
+  const hasToolCards = toolCards.length > 0;
+
+  const extractedText = extractText(message);
+  const extractedThinking =
+    opts.showReasoning && role === "assistant" ? extractThinking(message) : null;
+  const markdownBase = extractedText?.trim() ? extractedText : null;
+  const markdown = extractedThinking
+    ? [formatReasoningMarkdown(extractedThinking), markdownBase]
+        .filter(Boolean)
+        .join("\n\n")
+    : markdownBase;
+
+  const bubbleClasses = [
+    "chat-bubble",
+    opts.isStreaming ? "streaming" : "",
+    "fade-in",
+  ]
+    .filter(Boolean)
+    .join(" ");
+
+  if (!markdown && hasToolCards && isToolResult) {
+    return html`${toolCards.map((card) =>
+      renderToolCardSidebar(card, onOpenSidebar),
+    )}`;
+  }
+
+  if (!markdown && !hasToolCards) return nothing;
+
+  return html`
+    <div class="${bubbleClasses}">
+      ${markdown
+        ? html`<div class="chat-text">${unsafeHTML(toSanitizedMarkdownHtml(markdown))}</div>`
+        : nothing}
+      ${toolCards.map((card) => renderToolCardSidebar(card, onOpenSidebar))}
    </div>
  `;
 }
@@ -600,9 +884,3 @@ function extractToolText(item: Record<string, unknown>): string | undefined {
  if (typeof item.content === "string") return item.content;
  return undefined;
 }
-
-function isToolResultMessage(message: unknown): boolean {
-  const m = message as Record<string, unknown>;
-  const role = typeof m.role === "string" ? m.role.toLowerCase() : "";
-  return role === "toolresult" || role === "tool_result";
-}
--- a/ui/src/ui/views/markdown-sidebar.ts
+++ b/ui/src/ui/views/markdown-sidebar.ts
@@ -0,0 +1,36 @@
+import { html, nothing } from "lit";
+import { unsafeHTML } from "lit/directives/unsafe-html.js";
+
+import { toSanitizedMarkdownHtml } from "../markdown";
+
+export type MarkdownSidebarProps = {
+  content: string | null;
+  error: string | null;
+  onClose: () => void;
+  onViewRawText: () => void;
+};
+
+export function renderMarkdownSidebar(props: MarkdownSidebarProps) {
+  return html`
+    <div class="sidebar-panel">
+      <div class="sidebar-header">
+        <div class="sidebar-title">Tool Output</div>
+        <button @click=${props.onClose} class="btn" title="Close sidebar">
+          ✕
+        </button>
+      </div>
+      <div class="sidebar-content">
+        ${props.error
+          ? html`
+              <div class="callout danger">${props.error}</div>
+              <button @click=${props.onViewRawText} class="btn" style="margin-top: 12px;">
+                View Raw Text
+              </button>
+            `
+          : props.content
+            ? html`<div class="sidebar-markdown">${unsafeHTML(toSanitizedMarkdownHtml(props.content))}</div>`
+            : html`<div class="muted">No content available</div>`}
+      </div>
+    </div>
+  `;
+}