feat: promote mock UI patterns into design system

New components: KpiStrip, SplitPane, EntityList, LogViewer, StatusText
Extended: Card (title prop)
Refactored: AgentHealth to use DataTable
Updated: COMPONENT_GUIDE.md, Inventory demos

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

COMPONENT_GUIDE.md

@@ -33,6 +33,7 @@
 
 ### "I need to show status"
 - Dot indicator → **StatusDot** (live, stale, dead, success, warning, error, running)
+- Inline colored status value → **StatusText** (success, warning, error, running, muted — with optional bold)
 - Labeled status → **Badge** with semantic color
 - Removable label → **Tag**
 
@@ -57,6 +58,9 @@
 - Event log → **EventFeed**
 - Processing pipeline (Gantt view) → **ProcessorTimeline**
 - Processing pipeline (flow diagram) → **RouteFlow**
+- Row of summary KPIs → **KpiStrip** (horizontal strip with colored borders, trends, sparklines)
+- Scrollable log output → **LogViewer** (timestamped, severity-colored monospace entries)
+- Searchable, selectable entity list → **EntityList** (search header, selection highlighting, pairs with SplitPane)
 
 ### "I need to organize content"
 - Collapsible sections (standalone) → **Collapsible**
@@ -64,15 +68,17 @@
 - Tabbed content → **Tabs**
 - Tab switching with pill/segment style → **SegmentedTabs**
 - Side panel inspector → **DetailPanel**
+- Master/detail split layout → **SplitPane** (list on left, detail on right, configurable ratio)
 - Section with title + action → **SectionHeader**
 - Empty content placeholder → **EmptyState**
-- Grouped content box → **Card** (with optional accent)
+- Grouped content box → **Card** (with optional accent and title)
 - Grouped items with header + meta + footer → **GroupCard** (e.g., app instances)
 
 ### "I need to display text"
 - Code/JSON payload → **CodeBlock** (with line numbers, copy button)
 - Monospace inline text → **MonoText**
 - Keyboard shortcut hint → **KeyboardHint**
+- Colored inline status text → **StatusText** (semantic color + optional bold, see also "I need to show status")
 
 ### "I need to show people/users"
 - Single user avatar → **Avatar**
@@ -115,6 +121,13 @@ Row of StatCard components (each with optional Sparkline and trend)
 Below: charts (AreaChart, LineChart, BarChart)
 ```
 
+### Master/detail management pattern
+```
+SplitPane + EntityList for CRUD list/detail screens (users, groups, roles)
+  EntityList provides: search header, add button, selectable list
+  SplitPane provides: responsive two-column layout with empty state
+```
+
 ### Detail/inspector pattern
 ```
 DetailPanel (right slide) with Tabs for sections OR children for scrollable content
@@ -162,7 +175,7 @@ URL-driven progressive filtering: /agents → /agents/:appId → /agents/:appId/
 | Breadcrumb | composite | Navigation path showing current location |
 | Button | primitive | Action trigger (primary, secondary, danger, ghost) |
 | ButtonGroup | primitive | Multi-select toggle group with optional colored dot indicators. Props: items (value, label, color?), value (Set), onChange |
-| Card | primitive | Content container with optional accent border |
+| Card | primitive | Content container with optional accent border and title header |
 | Checkbox | primitive | Boolean input with label |
 | CodeBlock | primitive | Syntax-highlighted code/JSON display |
 | Collapsible | primitive | Single expand/collapse section |
@@ -174,6 +187,7 @@ URL-driven progressive filtering: /agents → /agents/:appId → /agents/:appId/
 | DetailPanel | composite | Slide-in side panel with tabs or children for scrollable content |
 | Dropdown | composite | Action menu triggered by any element |
 | EmptyState | primitive | Placeholder for empty content areas |
+| EntityList | composite | Searchable, selectable entity list with add button. Pair with SplitPane for CRUD management screens |
 | EventFeed | composite | Chronological event log with severity |
 | FilterBar | composite | Search + filter controls for data views |
 | GroupCard | composite | Card with header, meta row, children, and optional footer/alert. Used for grouping instances by application. |
@@ -183,8 +197,10 @@ URL-driven progressive filtering: /agents → /agents/:appId → /agents/:appId/
 | InlineEdit | primitive | Click-to-edit text field. Enter saves, Escape/blur cancels. Props: value, onSave, placeholder, disabled, className |
 | Input | primitive | Single-line text input with optional icon |
 | KeyboardHint | primitive | Keyboard shortcut display |
+| KpiStrip | composite | Horizontal row of KPI cards with colored left border, trend, subtitle, optional sparkline |
 | Label | primitive | Form label with optional required asterisk |
 | LineChart | composite | Time series line visualization |
+| LogViewer | composite | Scrollable log output with timestamped, severity-colored monospace entries |
 | MenuItem | composite | Sidebar navigation item with health/count |
 | Modal | composite | Generic dialog overlay with backdrop |
 | MultiSelect | composite | Dropdown with searchable checkbox list and Apply action. Props: options, value, onChange, placeholder, searchable, disabled, className |
@@ -202,9 +218,11 @@ URL-driven progressive filtering: /agents → /agents/:appId → /agents/:appId/
 | ShortcutsBar | composite | Keyboard shortcuts reference bar |
 | Skeleton | primitive | Loading placeholder (text, circular, rectangular) |
 | Sparkline | primitive | Inline mini chart for trends |
+| SplitPane | composite | Two-column master/detail layout with configurable ratio and empty state |
 | Spinner | primitive | Animated loading indicator |
 | StatCard | primitive | KPI card with value, trend, optional sparkline |
 | StatusDot | primitive | Colored dot for status indication |
+| StatusText | primitive | Inline colored status span (success, warning, error, running, muted) with optional bold |
 | Tabs | composite | Tabbed content switcher with optional counts |
 | Tag | primitive | Removable colored label |
 | Textarea | primitive | Multi-line text input with resize control |

src/design-system/composites/EntityList/EntityList.module.css

@@ -0,0 +1,49 @@
+.entityListRoot {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+}
+
+.listHeader {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 12px;
+  border-bottom: 1px solid var(--border-subtle);
+}
+
+.listHeaderSearch {
+  flex: 1;
+}
+
+.list {
+  flex: 1;
+  overflow-y: auto;
+}
+
+.entityItem {
+  display: flex;
+  align-items: flex-start;
+  gap: 10px;
+  padding: 10px 12px;
+  cursor: pointer;
+  transition: background 0.1s;
+  border-bottom: 1px solid var(--border-subtle);
+}
+
+.entityItem:hover {
+  background: var(--bg-hover);
+}
+
+.entityItemSelected {
+  background: var(--amber-bg);
+  border-left: 3px solid var(--amber);
+}
+
+.emptyMessage {
+  padding: 32px;
+  text-align: center;
+  color: var(--text-faint);
+  font-size: 12px;
+  font-family: var(--font-body);
+}

src/design-system/composites/EntityList/EntityList.test.tsx

@@ -0,0 +1,167 @@
+import { describe, it, expect, vi } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { EntityList } from './EntityList'
+
+interface TestItem {
+  id: string
+  name: string
+}
+
+const items: TestItem[] = [
+  { id: '1', name: 'Alpha' },
+  { id: '2', name: 'Beta' },
+  { id: '3', name: 'Gamma' },
+]
+
+describe('EntityList', () => {
+  it('renders all items', () => {
+    render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+      />
+    )
+    expect(screen.getByText('Alpha')).toBeInTheDocument()
+    expect(screen.getByText('Beta')).toBeInTheDocument()
+    expect(screen.getByText('Gamma')).toBeInTheDocument()
+  })
+
+  it('calls onSelect when item clicked', async () => {
+    const onSelect = vi.fn()
+    const user = userEvent.setup()
+    render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+        onSelect={onSelect}
+      />
+    )
+    await user.click(screen.getByText('Beta'))
+    expect(onSelect).toHaveBeenCalledWith('2')
+  })
+
+  it('highlights selected item (aria-selected="true" and has selected class)', () => {
+    render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+        selectedId="2"
+      />
+    )
+    const selectedOption = screen.getByText('Beta').closest('[role="option"]')
+    expect(selectedOption).toHaveAttribute('aria-selected', 'true')
+
+    const unselectedOption = screen.getByText('Alpha').closest('[role="option"]')
+    expect(unselectedOption).toHaveAttribute('aria-selected', 'false')
+  })
+
+  it('renders search input when onSearch provided', () => {
+    render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+        onSearch={() => {}}
+        searchPlaceholder="Filter items..."
+      />
+    )
+    expect(screen.getByPlaceholderText('Filter items...')).toBeInTheDocument()
+  })
+
+  it('calls onSearch when typing in search', async () => {
+    const onSearch = vi.fn()
+    const user = userEvent.setup()
+    render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+        onSearch={onSearch}
+      />
+    )
+    const input = screen.getByPlaceholderText('Search...')
+    await user.type(input, 'test')
+    expect(onSearch).toHaveBeenLastCalledWith('test')
+  })
+
+  it('renders add button when onAdd provided', () => {
+    render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+        onAdd={() => {}}
+        addLabel="Add Item"
+      />
+    )
+    expect(screen.getByText('Add Item')).toBeInTheDocument()
+  })
+
+  it('calls onAdd when add button clicked', async () => {
+    const onAdd = vi.fn()
+    const user = userEvent.setup()
+    render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+        onAdd={onAdd}
+        addLabel="Add Item"
+      />
+    )
+    await user.click(screen.getByText('Add Item'))
+    expect(onAdd).toHaveBeenCalledOnce()
+  })
+
+  it('hides header when no search or add', () => {
+    const { container } = render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+      />
+    )
+    // No input or button should be present in the header area
+    expect(container.querySelector('input')).toBeNull()
+    expect(container.querySelector('button')).toBeNull()
+  })
+
+  it('shows empty message when items is empty', () => {
+    render(
+      <EntityList
+        items={[]}
+        renderItem={(item: TestItem) => <span>{item.name}</span>}
+        getItemId={(item: TestItem) => item.id}
+      />
+    )
+    expect(screen.getByText('No items found')).toBeInTheDocument()
+  })
+
+  it('shows custom empty message', () => {
+    render(
+      <EntityList
+        items={[]}
+        renderItem={(item: TestItem) => <span>{item.name}</span>}
+        getItemId={(item: TestItem) => item.id}
+        emptyMessage="Nothing here"
+      />
+    )
+    expect(screen.getByText('Nothing here')).toBeInTheDocument()
+  })
+
+  it('accepts className', () => {
+    const { container } = render(
+      <EntityList
+        items={items}
+        renderItem={(item) => <span>{item.name}</span>}
+        getItemId={(item) => item.id}
+        className="custom-class"
+      />
+    )
+    expect(container.firstChild).toHaveClass('custom-class')
+  })
+})

src/design-system/composites/EntityList/EntityList.tsx

@@ -0,0 +1,97 @@
+import { useState, type ReactNode } from 'react'
+import { Input } from '../../primitives/Input/Input'
+import { Button } from '../../primitives/Button/Button'
+import styles from './EntityList.module.css'
+
+interface EntityListProps<T> {
+  items: T[]
+  renderItem: (item: T, isSelected: boolean) => ReactNode
+  getItemId: (item: T) => string
+  selectedId?: string
+  onSelect?: (id: string) => void
+  searchPlaceholder?: string
+  onSearch?: (query: string) => void
+  addLabel?: string
+  onAdd?: () => void
+  emptyMessage?: string
+  className?: string
+}
+
+export function EntityList<T>({
+  items,
+  renderItem,
+  getItemId,
+  selectedId,
+  onSelect,
+  searchPlaceholder = 'Search...',
+  onSearch,
+  addLabel,
+  onAdd,
+  emptyMessage = 'No items found',
+  className,
+}: EntityListProps<T>) {
+  const [searchValue, setSearchValue] = useState('')
+  const showHeader = !!onSearch || !!onAdd
+
+  function handleSearchChange(e: React.ChangeEvent<HTMLInputElement>) {
+    const value = e.target.value
+    setSearchValue(value)
+    onSearch?.(value)
+  }
+
+  function handleSearchClear() {
+    setSearchValue('')
+    onSearch?.('')
+  }
+
+  return (
+    <div className={`${styles.entityListRoot} ${className ?? ''}`}>
+      {showHeader && (
+        <div className={styles.listHeader}>
+          {onSearch && (
+            <Input
+              placeholder={searchPlaceholder}
+              value={searchValue}
+              onChange={handleSearchChange}
+              onClear={handleSearchClear}
+              className={styles.listHeaderSearch}
+            />
+          )}
+          {onAdd && addLabel && (
+            <Button size="sm" variant="secondary" onClick={onAdd}>
+              {addLabel}
+            </Button>
+          )}
+        </div>
+      )}
+
+      <div className={styles.list} role="listbox">
+        {items.map((item) => {
+          const id = getItemId(item)
+          const isSelected = id === selectedId
+          return (
+            <div
+              key={id}
+              className={`${styles.entityItem} ${isSelected ? styles.entityItemSelected : ''}`}
+              onClick={() => onSelect?.(id)}
+              role="option"
+              tabIndex={0}
+              aria-selected={isSelected}
+              onKeyDown={(e) => {
+                if (e.key === 'Enter' || e.key === ' ') {
+                  e.preventDefault()
+                  onSelect?.(id)
+                }
+              }}
+            >
+              {renderItem(item, isSelected)}
+            </div>
+          )
+        })}
+        {items.length === 0 && (
+          <div className={styles.emptyMessage}>{emptyMessage}</div>
+        )}
+      </div>
+    </div>
+  )
+}

src/design-system/composites/KpiStrip/KpiStrip.module.css

@@ -0,0 +1,79 @@
+.kpiStrip {
+  display: grid;
+  gap: 12px;
+  margin-bottom: 20px;
+}
+
+.kpiCard {
+  background: var(--bg-surface);
+  border: 1px solid var(--border-subtle);
+  border-radius: var(--radius-lg);
+  padding: 16px 18px 12px;
+  box-shadow: var(--shadow-card);
+  position: relative;
+  overflow: hidden;
+  transition: box-shadow 0.15s;
+}
+
+.kpiCard:hover {
+  box-shadow: var(--shadow-md);
+}
+
+.kpiCard::before {
+  content: '';
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  height: 3px;
+  background: linear-gradient(90deg, var(--kpi-border-color), transparent);
+}
+
+.label {
+  font-size: 10px;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.6px;
+  color: var(--text-muted);
+  margin-bottom: 6px;
+}
+
+.valueRow {
+  display: flex;
+  align-items: baseline;
+  gap: 6px;
+  margin-bottom: 4px;
+}
+
+.value {
+  font-family: var(--font-mono);
+  font-size: 26px;
+  font-weight: 600;
+  line-height: 1.2;
+  color: var(--text-primary);
+}
+
+.trend {
+  font-family: var(--font-mono);
+  font-size: 11px;
+  display: inline-flex;
+  align-items: center;
+  gap: 2px;
+  margin-left: auto;
+}
+
+.trendSuccess { color: var(--success); }
+.trendWarning { color: var(--warning); }
+.trendError   { color: var(--error); }
+.trendMuted   { color: var(--text-muted); }
+
+.subtitle {
+  font-size: 11px;
+  color: var(--text-muted);
+  margin-top: 2px;
+}
+
+.sparkline {
+  margin-top: 8px;
+  height: 32px;
+}

src/design-system/composites/KpiStrip/KpiStrip.test.tsx

@@ -0,0 +1,86 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import { KpiStrip } from './KpiStrip'
+import type { KpiItem } from './KpiStrip'
+
+const sampleItems: KpiItem[] = [
+  { label: 'Total', value: 42 },
+  { label: 'Active', value: '18', trend: { label: '+3', variant: 'success' } },
+  { label: 'Errors', value: 5, subtitle: 'last 24h', sparkline: [1, 3, 2, 5, 4] },
+]
+
+describe('KpiStrip', () => {
+  it('renders all items', () => {
+    const { container } = render(<KpiStrip items={sampleItems} />)
+    const cards = container.querySelectorAll('[class*="kpiCard"]')
+    expect(cards).toHaveLength(3)
+  })
+
+  it('renders labels and values', () => {
+    render(<KpiStrip items={sampleItems} />)
+    expect(screen.getByText('Total')).toBeInTheDocument()
+    expect(screen.getByText('42')).toBeInTheDocument()
+    expect(screen.getByText('Active')).toBeInTheDocument()
+    expect(screen.getByText('18')).toBeInTheDocument()
+  })
+
+  it('renders trend with correct text', () => {
+    render(<KpiStrip items={sampleItems} />)
+    expect(screen.getByText('+3')).toBeInTheDocument()
+  })
+
+  it('applies variant class to trend (trendSuccess)', () => {
+    render(<KpiStrip items={sampleItems} />)
+    const trend = screen.getByText('+3')
+    expect(trend.className).toContain('trendSuccess')
+  })
+
+  it('hides trend when omitted', () => {
+    render(<KpiStrip items={[{ label: 'No Trend', value: 10 }]} />)
+    const { container } = render(<KpiStrip items={[{ label: 'No Trend2', value: 10 }]} />)
+    const trends = container.querySelectorAll('[class*="trend"]')
+    expect(trends).toHaveLength(0)
+  })
+
+  it('renders subtitle', () => {
+    render(<KpiStrip items={sampleItems} />)
+    expect(screen.getByText('last 24h')).toBeInTheDocument()
+  })
+
+  it('renders sparkline when data provided', () => {
+    const { container } = render(<KpiStrip items={sampleItems} />)
+    const svgs = container.querySelectorAll('svg')
+    expect(svgs.length).toBeGreaterThanOrEqual(1)
+  })
+
+  it('accepts className prop', () => {
+    const { container } = render(<KpiStrip items={sampleItems} className="custom" />)
+    expect(container.firstChild).toHaveClass('custom')
+  })
+
+  it('handles empty items array', () => {
+    const { container } = render(<KpiStrip items={[]} />)
+    const cards = container.querySelectorAll('[class*="kpiCard"]')
+    expect(cards).toHaveLength(0)
+  })
+
+  it('uses default border color (--amber) when borderColor omitted', () => {
+    const { container } = render(<KpiStrip items={[{ label: 'Default', value: 1 }]} />)
+    const card = container.querySelector('[class*="kpiCard"]') as HTMLElement
+    expect(card.style.getPropertyValue('--kpi-border-color')).toBe('var(--amber)')
+  })
+
+  it('applies custom borderColor', () => {
+    const items: KpiItem[] = [{ label: 'Custom', value: 1, borderColor: 'var(--teal)' }]
+    const { container } = render(<KpiStrip items={items} />)
+    const card = container.querySelector('[class*="kpiCard"]') as HTMLElement
+    expect(card.style.getPropertyValue('--kpi-border-color')).toBe('var(--teal)')
+  })
+
+  it('renders trend with muted variant by default', () => {
+    const items: KpiItem[] = [{ label: 'Muted', value: 1, trend: { label: '0%' } }]
+    render(<KpiStrip items={items} />)
+    const trend = screen.getByText('0%')
+    expect(trend.className).toContain('trendMuted')
+  })
+})

src/design-system/composites/KpiStrip/KpiStrip.tsx

@@ -0,0 +1,71 @@
+import styles from './KpiStrip.module.css'
+import { Sparkline } from '../../primitives/Sparkline/Sparkline'
+import type { CSSProperties } from 'react'
+
+export interface KpiItem {
+  label: string
+  value: string | number
+  trend?: { label: string; variant?: 'success' | 'warning' | 'error' | 'muted' }
+  subtitle?: string
+  sparkline?: number[]
+  borderColor?: string
+}
+
+export interface KpiStripProps {
+  items: KpiItem[]
+  className?: string
+}
+
+const trendClassMap: Record<string, string> = {
+  success: styles.trendSuccess,
+  warning: styles.trendWarning,
+  error: styles.trendError,
+  muted: styles.trendMuted,
+}
+
+export function KpiStrip({ items, className }: KpiStripProps) {
+  const stripClasses = [styles.kpiStrip, className ?? ''].filter(Boolean).join(' ')
+  const gridStyle: CSSProperties = {
+    gridTemplateColumns: items.length > 0 ? `repeat(${items.length}, 1fr)` : undefined,
+  }
+
+  return (
+    <div className={stripClasses} style={gridStyle}>
+      {items.map((item) => {
+        const borderColor = item.borderColor ?? 'var(--amber)'
+        const cardStyle: CSSProperties & Record<string, string> = {
+          '--kpi-border-color': borderColor,
+        }
+        const trendVariant = item.trend?.variant ?? 'muted'
+        const trendClass = trendClassMap[trendVariant] ?? styles.trendMuted
+
+        return (
+          <div key={item.label} className={styles.kpiCard} style={cardStyle}>
+            <div className={styles.label}>{item.label}</div>
+            <div className={styles.valueRow}>
+              <span className={styles.value}>{item.value}</span>
+              {item.trend && (
+                <span className={`${styles.trend} ${trendClass}`}>
+                  {item.trend.label}
+                </span>
+              )}
+            </div>
+            {item.subtitle && (
+              <div className={styles.subtitle}>{item.subtitle}</div>
+            )}
+            {item.sparkline && item.sparkline.length >= 2 && (
+              <div className={styles.sparkline}>
+                <Sparkline
+                  data={item.sparkline}
+                  color={borderColor}
+                  width={200}
+                  height={32}
+                />
+              </div>
+            )}
+          </div>
+        )
+      })}
+    </div>
+  )
+}

src/design-system/composites/LogViewer/LogViewer.module.css

@@ -0,0 +1,75 @@
+.container {
+  overflow-y: auto;
+  background: var(--bg-inset);
+  border-radius: var(--radius-md);
+  padding: 8px 0;
+  font-family: var(--font-mono);
+}
+
+.line {
+  display: flex;
+  align-items: flex-start;
+  gap: 8px;
+  padding: 3px 12px;
+  line-height: 1.5;
+}
+
+.line:hover {
+  background: var(--bg-hover);
+}
+
+.timestamp {
+  flex-shrink: 0;
+  font-size: 11px;
+  color: var(--text-muted);
+  min-width: 56px;
+}
+
+.levelBadge {
+  flex-shrink: 0;
+  font-size: 9px;
+  font-weight: 600;
+  font-family: var(--font-mono);
+  text-transform: uppercase;
+  letter-spacing: 0.3px;
+  padding: 1px 6px;
+  border-radius: 9999px;
+  line-height: 1.5;
+  white-space: nowrap;
+}
+
+.levelInfo {
+  color: var(--running);
+  background: color-mix(in srgb, var(--running) 12%, transparent);
+}
+
+.levelWarn {
+  color: var(--warning);
+  background: color-mix(in srgb, var(--warning) 12%, transparent);
+}
+
+.levelError {
+  color: var(--error);
+  background: color-mix(in srgb, var(--error) 12%, transparent);
+}
+
+.levelDebug {
+  color: var(--text-muted);
+  background: color-mix(in srgb, var(--text-muted) 10%, transparent);
+}
+
+.message {
+  font-size: 12px;
+  font-family: var(--font-mono);
+  color: var(--text-primary);
+  word-break: break-word;
+  line-height: 1.5;
+}
+
+.empty {
+  padding: 24px;
+  text-align: center;
+  color: var(--text-faint);
+  font-size: 12px;
+  font-family: var(--font-body);
+}

src/design-system/composites/LogViewer/LogViewer.test.tsx

@@ -0,0 +1,56 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import { LogViewer, type LogEntry } from './LogViewer'
+
+const entries: LogEntry[] = [
+  { timestamp: '2024-01-15T10:30:00Z', level: 'info', message: 'Server started' },
+  { timestamp: '2024-01-15T10:30:05Z', level: 'warn', message: 'High memory usage' },
+  { timestamp: '2024-01-15T10:30:10Z', level: 'error', message: 'Connection failed' },
+  { timestamp: '2024-01-15T10:30:15Z', level: 'debug', message: 'Query executed in 3ms' },
+]
+
+describe('LogViewer', () => {
+  it('renders entries with timestamps and messages', () => {
+    render(<LogViewer entries={entries} />)
+    expect(screen.getByText('Server started')).toBeInTheDocument()
+    expect(screen.getByText('High memory usage')).toBeInTheDocument()
+    expect(screen.getByText('Connection failed')).toBeInTheDocument()
+    expect(screen.getByText('Query executed in 3ms')).toBeInTheDocument()
+  })
+
+  it('renders level badges with correct text (INFO, WARN, ERROR, DEBUG)', () => {
+    render(<LogViewer entries={entries} />)
+    expect(screen.getByText('INFO')).toBeInTheDocument()
+    expect(screen.getByText('WARN')).toBeInTheDocument()
+    expect(screen.getByText('ERROR')).toBeInTheDocument()
+    expect(screen.getByText('DEBUG')).toBeInTheDocument()
+  })
+
+  it('renders with custom maxHeight (number)', () => {
+    const { container } = render(<LogViewer entries={entries} maxHeight={300} />)
+    const el = container.firstElementChild as HTMLElement
+    expect(el.style.maxHeight).toBe('300px')
+  })
+
+  it('renders with string maxHeight', () => {
+    const { container } = render(<LogViewer entries={entries} maxHeight="50vh" />)
+    const el = container.firstElementChild as HTMLElement
+    expect(el.style.maxHeight).toBe('50vh')
+  })
+
+  it('handles empty entries', () => {
+    render(<LogViewer entries={[]} />)
+    expect(screen.getByText('No log entries.')).toBeInTheDocument()
+  })
+
+  it('accepts className prop', () => {
+    const { container } = render(<LogViewer entries={entries} className="custom-class" />)
+    const el = container.firstElementChild as HTMLElement
+    expect(el.classList.contains('custom-class')).toBe(true)
+  })
+
+  it('has role="log" for accessibility', () => {
+    render(<LogViewer entries={entries} />)
+    expect(screen.getByRole('log')).toBeInTheDocument()
+  })
+})

src/design-system/composites/LogViewer/LogViewer.tsx

@@ -0,0 +1,77 @@
+import { useRef, useEffect, useCallback } from 'react'
+import styles from './LogViewer.module.css'
+
+export interface LogEntry {
+  timestamp: string
+  level: 'info' | 'warn' | 'error' | 'debug'
+  message: string
+}
+
+export interface LogViewerProps {
+  entries: LogEntry[]
+  maxHeight?: number | string
+  className?: string
+}
+
+const LEVEL_CLASS: Record<LogEntry['level'], string> = {
+  info: styles.levelInfo,
+  warn: styles.levelWarn,
+  error: styles.levelError,
+  debug: styles.levelDebug,
+}
+
+function formatTime(iso: string): string {
+  try {
+    return new Date(iso).toLocaleTimeString('en-GB', {
+      hour: '2-digit',
+      minute: '2-digit',
+      second: '2-digit',
+      hour12: false,
+    })
+  } catch {
+    return iso
+  }
+}
+
+export function LogViewer({ entries, maxHeight = 400, className }: LogViewerProps) {
+  const scrollRef = useRef<HTMLDivElement>(null)
+  const isAtBottomRef = useRef(true)
+
+  const handleScroll = useCallback(() => {
+    const el = scrollRef.current
+    if (!el) return
+    isAtBottomRef.current = el.scrollHeight - el.scrollTop - el.clientHeight < 20
+  }, [])
+
+  useEffect(() => {
+    const el = scrollRef.current
+    if (el && isAtBottomRef.current) {
+      el.scrollTop = el.scrollHeight
+    }
+  }, [entries])
+
+  const heightStyle = typeof maxHeight === 'number' ? `${maxHeight}px` : maxHeight
+
+  return (
+    <div
+      ref={scrollRef}
+      className={[styles.container, className].filter(Boolean).join(' ')}
+      style={{ maxHeight: heightStyle }}
+      onScroll={handleScroll}
+      role="log"
+    >
+      {entries.map((entry, i) => (
+        <div key={i} className={styles.line}>
+          <span className={styles.timestamp}>{formatTime(entry.timestamp)}</span>
+          <span className={[styles.levelBadge, LEVEL_CLASS[entry.level]].join(' ')}>
+            {entry.level.toUpperCase()}
+          </span>
+          <span className={styles.message}>{entry.message}</span>
+        </div>
+      ))}
+      {entries.length === 0 && (
+        <div className={styles.empty}>No log entries.</div>
+      )}
+    </div>
+  )
+}

src/design-system/composites/SplitPane/SplitPane.module.css

@@ -0,0 +1,37 @@
+.splitPane {
+  display: grid;
+  grid-template-columns: var(--split-columns, 1fr 2fr);
+  gap: 1px;
+  background: var(--border-subtle);
+  border: 1px solid var(--border-subtle);
+  border-radius: var(--radius-lg);
+  min-height: 0;
+  height: 100%;
+  box-shadow: var(--shadow-card);
+}
+
+.listPane {
+  background: var(--bg-surface);
+  display: flex;
+  flex-direction: column;
+  border-radius: var(--radius-lg) 0 0 var(--radius-lg);
+  overflow-y: auto;
+}
+
+.detailPane {
+  background: var(--bg-raised);
+  overflow-y: auto;
+  padding: 20px;
+  border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
+}
+
+.emptyDetail {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  height: 100%;
+  color: var(--text-faint);
+  font-size: 13px;
+  font-family: var(--font-body);
+  font-style: italic;
+}

src/design-system/composites/SplitPane/SplitPane.test.tsx

@@ -0,0 +1,69 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import { SplitPane } from './SplitPane'
+
+describe('SplitPane', () => {
+  it('renders list and detail content', () => {
+    render(
+      <SplitPane
+        list={<div>List items</div>}
+        detail={<div>Detail content</div>}
+      />
+    )
+    expect(screen.getByText('List items')).toBeInTheDocument()
+    expect(screen.getByText('Detail content')).toBeInTheDocument()
+  })
+
+  it('shows default empty message when detail is null', () => {
+    render(
+      <SplitPane
+        list={<div>List items</div>}
+        detail={null}
+      />
+    )
+    expect(screen.getByText('Select an item to view details')).toBeInTheDocument()
+  })
+
+  it('shows custom empty message', () => {
+    render(
+      <SplitPane
+        list={<div>List items</div>}
+        detail={null}
+        emptyMessage="Pick something"
+      />
+    )
+    expect(screen.getByText('Pick something')).toBeInTheDocument()
+  })
+
+  it('renders with different ratios (checks --split-columns CSS property)', () => {
+    const { container, rerender } = render(
+      <SplitPane
+        list={<div>List</div>}
+        detail={<div>Detail</div>}
+        ratio="1:1"
+      />
+    )
+    const root = container.firstChild as HTMLElement
+    expect(root.style.getPropertyValue('--split-columns')).toBe('1fr 1fr')
+
+    rerender(
+      <SplitPane
+        list={<div>List</div>}
+        detail={<div>Detail</div>}
+        ratio="2:3"
+      />
+    )
+    expect(root.style.getPropertyValue('--split-columns')).toBe('2fr 3fr')
+  })
+
+  it('accepts className', () => {
+    const { container } = render(
+      <SplitPane
+        list={<div>List</div>}
+        detail={<div>Detail</div>}
+        className="custom-class"
+      />
+    )
+    expect(container.firstChild).toHaveClass('custom-class')
+  })
+})

src/design-system/composites/SplitPane/SplitPane.tsx

@@ -0,0 +1,38 @@
+import type { ReactNode } from 'react'
+import styles from './SplitPane.module.css'
+
+interface SplitPaneProps {
+  list: ReactNode
+  detail: ReactNode | null
+  emptyMessage?: string
+  ratio?: '1:1' | '1:2' | '2:3'
+  className?: string
+}
+
+const ratioMap: Record<string, string> = {
+  '1:1': '1fr 1fr',
+  '1:2': '1fr 2fr',
+  '2:3': '2fr 3fr',
+}
+
+export function SplitPane({
+  list,
+  detail,
+  emptyMessage = 'Select an item to view details',
+  ratio = '1:2',
+  className,
+}: SplitPaneProps) {
+  return (
+    <div
+      className={`${styles.splitPane} ${className ?? ''}`}
+      style={{ '--split-columns': ratioMap[ratio] } as React.CSSProperties}
+    >
+      <div className={styles.listPane}>{list}</div>
+      <div className={styles.detailPane}>
+        {detail !== null ? detail : (
+          <div className={styles.emptyDetail}>{emptyMessage}</div>
+        )}
+      </div>
+    </div>
+  )
+}

src/design-system/composites/index.ts

@@ -11,12 +11,17 @@ export type { ConfirmDialogProps } from './ConfirmDialog/ConfirmDialog'
 export { DataTable } from './DataTable/DataTable'
 export type { Column, DataTableProps } from './DataTable/types'
 export { DetailPanel } from './DetailPanel/DetailPanel'
+export { EntityList } from './EntityList/EntityList'
 export { Dropdown } from './Dropdown/Dropdown'
 export { EventFeed } from './EventFeed/EventFeed'
 export { GroupCard } from './GroupCard/GroupCard'
+export { KpiStrip } from './KpiStrip/KpiStrip'
+export type { KpiItem, KpiStripProps } from './KpiStrip/KpiStrip'
 export type { FeedEvent } from './EventFeed/EventFeed'
 export { FilterBar } from './FilterBar/FilterBar'
 export { LineChart } from './LineChart/LineChart'
+export { LogViewer } from './LogViewer/LogViewer'
+export type { LogEntry, LogViewerProps } from './LogViewer/LogViewer'
 export { LoginDialog } from './LoginForm/LoginDialog'
 export type { LoginDialogProps } from './LoginForm/LoginDialog'
 export { LoginForm } from './LoginForm/LoginForm'
@@ -32,6 +37,7 @@ export { RouteFlow } from './RouteFlow/RouteFlow'
 export type { RouteNode } from './RouteFlow/RouteFlow'
 export { ShortcutsBar } from './ShortcutsBar/ShortcutsBar'
 export { SegmentedTabs } from './SegmentedTabs/SegmentedTabs'
+export { SplitPane } from './SplitPane/SplitPane'
 export { Tabs } from './Tabs/Tabs'
 export { ToastProvider, useToast } from './Toast/Toast'
 export { TreeView } from './TreeView/TreeView'

src/design-system/primitives/Card/Card.module.css

@@ -11,3 +11,22 @@
 .accent-warning { border-top: 3px solid var(--warning); }
 .accent-error   { border-top: 3px solid var(--error); }
 .accent-running { border-top: 3px solid var(--running); }
+
+.titleHeader {
+  padding: 12px 16px;
+  border-bottom: 1px solid var(--border-subtle);
+}
+
+.titleText {
+  font-size: 11px;
+  text-transform: uppercase;
+  font-family: var(--font-mono);
+  font-weight: 600;
+  color: var(--text-secondary);
+  letter-spacing: 0.5px;
+  margin: 0;
+}
+
+.body {
+  padding: 16px;
+}

src/design-system/primitives/Card/Card.test.tsx

@@ -0,0 +1,49 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import { Card } from './Card'
+
+describe('Card', () => {
+  it('renders children', () => {
+    render(<Card>Hello world</Card>)
+    expect(screen.getByText('Hello world')).toBeInTheDocument()
+  })
+
+  it('renders title when provided', () => {
+    render(<Card title="Status">Content</Card>)
+    expect(screen.getByText('Status')).toBeInTheDocument()
+  })
+
+  it('does not render title header when title is omitted', () => {
+    const { container } = render(<Card>Content</Card>)
+    expect(container.querySelector('h3')).toBeNull()
+  })
+
+  it('wraps children in body div when title is provided', () => {
+    render(<Card title="Status"><span>Content</span></Card>)
+    const content = screen.getByText('Content')
+    expect(content.parentElement).toHaveClass('body')
+  })
+
+  it('renders with accent and title together', () => {
+    const { container } = render(
+      <Card accent="success" title="Health">Content</Card>,
+    )
+    const card = container.firstChild as HTMLElement
+    expect(card).toHaveClass('accent-success')
+    expect(screen.getByText('Health')).toBeInTheDocument()
+    expect(screen.getByText('Content')).toBeInTheDocument()
+  })
+
+  it('accepts className prop', () => {
+    const { container } = render(<Card className="custom">Content</Card>)
+    const card = container.firstChild as HTMLElement
+    expect(card).toHaveClass('custom')
+  })
+
+  it('renders children directly when no title (no wrapper div)', () => {
+    const { container } = render(<Card><span>Direct child</span></Card>)
+    const card = container.firstChild as HTMLElement
+    const span = screen.getByText('Direct child')
+    expect(span.parentElement).toBe(card)
+  })
+})

src/design-system/primitives/Card/Card.tsx

@@ -4,15 +4,25 @@ import type { ReactNode } from 'react'
 interface CardProps {
   children: ReactNode
   accent?: 'amber' | 'success' | 'warning' | 'error' | 'running' | 'none'
+  title?: string
   className?: string
 }
 
-export function Card({ children, accent = 'none', className }: CardProps) {
+export function Card({ children, accent = 'none', title, className }: CardProps) {
   const classes = [
     styles.card,
     accent !== 'none' ? styles[`accent-${accent}`] : '',
     className ?? '',
   ].filter(Boolean).join(' ')
 
-  return <div className={classes}>{children}</div>
+  return (
+    <div className={classes}>
+      {title && (
+        <div className={styles.titleHeader}>
+          <h3 className={styles.titleText}>{title}</h3>
+        </div>
+      )}
+      {title ? <div className={styles.body}>{children}</div> : children}
+    </div>
+  )
 }

src/design-system/primitives/StatusText/StatusText.module.css

@@ -0,0 +1,7 @@
+.statusText {}
+.success { color: var(--success); }
+.warning { color: var(--warning); }
+.error   { color: var(--error); }
+.running { color: var(--running); }
+.muted   { color: var(--text-muted); }
+.bold { font-weight: 600; }

src/design-system/primitives/StatusText/StatusText.test.tsx

@@ -0,0 +1,47 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import { StatusText } from './StatusText'
+
+describe('StatusText', () => {
+  it('renders children text', () => {
+    render(<StatusText variant="success">Online</StatusText>)
+    expect(screen.getByText('Online')).toBeInTheDocument()
+  })
+
+  it('renders as a span element', () => {
+    render(<StatusText variant="success">Status</StatusText>)
+    const el = screen.getByText('Status')
+    expect(el.tagName).toBe('SPAN')
+  })
+
+  it('applies variant class', () => {
+    render(<StatusText variant="error">Failed</StatusText>)
+    expect(screen.getByText('Failed')).toHaveClass('error')
+  })
+
+  it('applies bold class when bold=true', () => {
+    render(<StatusText variant="success" bold>OK</StatusText>)
+    expect(screen.getByText('OK')).toHaveClass('bold')
+  })
+
+  it('does not apply bold class by default', () => {
+    render(<StatusText variant="success">OK</StatusText>)
+    expect(screen.getByText('OK')).not.toHaveClass('bold')
+  })
+
+  it('accepts custom className', () => {
+    render(<StatusText variant="muted" className="custom">Text</StatusText>)
+    expect(screen.getByText('Text')).toHaveClass('custom')
+  })
+
+  it('renders all 5 variant classes correctly', () => {
+    const variants = ['success', 'warning', 'error', 'running', 'muted'] as const
+    for (const variant of variants) {
+      const { unmount } = render(
+        <StatusText variant={variant}>{variant}</StatusText>
+      )
+      expect(screen.getByText(variant)).toHaveClass(variant)
+      unmount()
+    }
+  })
+})

src/design-system/primitives/StatusText/StatusText.tsx

@@ -0,0 +1,20 @@
+import styles from './StatusText.module.css'
+import type { ReactNode } from 'react'
+
+interface StatusTextProps {
+  variant: 'success' | 'warning' | 'error' | 'running' | 'muted'
+  bold?: boolean
+  children: ReactNode
+  className?: string
+}
+
+export function StatusText({ variant, bold = false, children, className }: StatusTextProps) {
+  const classes = [
+    styles.statusText,
+    styles[variant],
+    bold ? styles.bold : '',
+    className ?? '',
+  ].filter(Boolean).join(' ')
+
+  return <span className={classes}>{children}</span>
+}

src/design-system/primitives/index.ts

@@ -30,6 +30,7 @@ export { Sparkline } from './Sparkline/Sparkline'
 export { Spinner } from './Spinner/Spinner'
 export { StatCard } from './StatCard/StatCard'
 export { StatusDot } from './StatusDot/StatusDot'
+export { StatusText } from './StatusText/StatusText'
 export { Tag } from './Tag/Tag'
 export { Textarea } from './Textarea/Textarea'
 export { TimeRangeDropdown } from './TimeRangeDropdown/TimeRangeDropdown'

src/pages/AgentHealth/AgentHealth.module.css

@@ -96,16 +96,6 @@
   margin-bottom: 20px;
 }
 
-/* Instance count badge in group header */
-.instanceCountBadge {
-  font-size: 11px;
-  font-family: var(--font-mono);
-  color: var(--text-muted);
-  background: var(--bg-inset);
-  padding: 2px 8px;
-  border-radius: 10px;
-}
-
 /* Group meta row */
 .groupMeta {
   display: flex;
@@ -138,62 +128,6 @@
   flex-shrink: 0;
 }
 
-/* Instance table */
-.instanceTable {
-  width: 100%;
-  border-collapse: collapse;
-  font-size: 12px;
-}
-
-.instanceTable thead th {
-  padding: 4px 12px;
-  font-size: 9px;
-  font-weight: 600;
-  text-transform: uppercase;
-  letter-spacing: 0.5px;
-  color: var(--text-faint);
-  text-align: left;
-  border-bottom: 1px solid var(--border-subtle);
-  white-space: nowrap;
-}
-
-.thStatus {
-  width: 12px;
-}
-
-.tdStatus {
-  width: 12px;
-  text-align: center;
-}
-
-/* Instance row */
-.instanceRow {
-  cursor: pointer;
-  transition: background 0.1s;
-}
-
-.instanceRow td {
-  padding: 8px 12px;
-  border-bottom: 1px solid var(--border-subtle);
-  white-space: nowrap;
-}
-
-.instanceRow:last-child td {
-  border-bottom: none;
-}
-
-.instanceRow:hover td {
-  background: var(--bg-hover);
-}
-
-.instanceRowActive td {
-  background: var(--amber-bg);
-}
-
-.instanceRowActive td:first-child {
-  box-shadow: inset 3px 0 0 var(--amber);
-}
-
 /* Instance fields */
 .instanceName {
   font-weight: 600;

src/pages/AgentHealth/AgentHealth.tsx

@@ -9,9 +9,11 @@ import { TopBar } from '../../design-system/layout/TopBar/TopBar'
 
 // Composites
 import { GroupCard } from '../../design-system/composites/GroupCard/GroupCard'
+import { DataTable } from '../../design-system/composites/DataTable/DataTable'
 import { LineChart } from '../../design-system/composites/LineChart/LineChart'
 import { EventFeed } from '../../design-system/composites/EventFeed/EventFeed'
 import { DetailPanel } from '../../design-system/composites/DetailPanel/DetailPanel'
+import type { Column } from '../../design-system/composites/DataTable/types'
 
 // Primitives
 import { StatusDot } from '../../design-system/primitives/StatusDot/StatusDot'
@@ -143,6 +145,72 @@ export function AgentHealth() {
   // Build trend data for selected instance
   const trendData = selectedInstance ? buildTrendData(selectedInstance) : null
 
+  // Column definitions for the instance DataTable
+  const instanceColumns: Column<AgentHealthData>[] = useMemo(() => [
+    {
+      key: 'status',
+      header: '',
+      width: '12px',
+      render: (_val, row) => (
+        <StatusDot variant={row.status === 'live' ? 'live' : row.status === 'stale' ? 'stale' : 'dead'} />
+      ),
+    },
+    {
+      key: 'name',
+      header: 'Instance',
+      render: (_val, row) => (
+        <MonoText size="sm" className={styles.instanceName}>{row.name}</MonoText>
+      ),
+    },
+    {
+      key: 'state',
+      header: 'State',
+      render: (_val, row) => (
+        <Badge
+          label={row.status.toUpperCase()}
+          color={row.status === 'live' ? 'success' : row.status === 'stale' ? 'warning' : 'error'}
+          variant="filled"
+        />
+      ),
+    },
+    {
+      key: 'uptime',
+      header: 'Uptime',
+      render: (_val, row) => (
+        <MonoText size="xs" className={styles.instanceMeta}>{row.uptime}</MonoText>
+      ),
+    },
+    {
+      key: 'tps',
+      header: 'TPS',
+      render: (_val, row) => (
+        <MonoText size="xs" className={styles.instanceMeta}>{row.tps.toFixed(1)}/s</MonoText>
+      ),
+    },
+    {
+      key: 'errorRate',
+      header: 'Errors',
+      render: (_val, row) => (
+        <MonoText size="xs" className={row.errorRate ? styles.instanceError : styles.instanceMeta}>
+          {row.errorRate ?? '0 err/h'}
+        </MonoText>
+      ),
+    },
+    {
+      key: 'lastSeen',
+      header: 'Heartbeat',
+      render: (_val, row) => (
+        <MonoText size="xs" className={
+          row.status === 'dead' ? styles.instanceHeartbeatDead :
+          row.status === 'stale' ? styles.instanceHeartbeatStale :
+          styles.instanceMeta
+        }>
+          {row.lastSeen}
+        </MonoText>
+      ),
+    },
+  ], [])
+
   function handleInstanceClick(inst: AgentHealthData) {
     setSelectedInstance(inst)
     setPanelOpen(true)
@@ -362,65 +430,14 @@ export function AgentHealth() {
                 </div>
               ) : undefined}
             >
-              <table className={styles.instanceTable}>
+              <DataTable<AgentHealthData>
-                <thead>
+                columns={instanceColumns}
-                  <tr>
+                data={group.instances}
-                    <th className={styles.thStatus} />
+                onRowClick={handleInstanceClick}
-                    <th>Instance</th>
+                selectedId={panelOpen ? selectedInstance?.id : undefined}
-                    <th>State</th>
+                pageSize={50}
-                    <th>Uptime</th>
+                flush
-                    <th>TPS</th>
-                    <th>Errors</th>
-                    <th>Heartbeat</th>
-                  </tr>
-                </thead>
-                <tbody>
-                  {group.instances.map((inst) => (
-                    <tr
-                      key={inst.id}
-                      className={[
-                        styles.instanceRow,
-                        selectedInstance?.id === inst.id && panelOpen ? styles.instanceRowActive : '',
-                      ].filter(Boolean).join(' ')}
-                      onClick={() => handleInstanceClick(inst)}
-                    >
-                      <td className={styles.tdStatus}>
-                        <StatusDot variant={inst.status === 'live' ? 'live' : inst.status === 'stale' ? 'stale' : 'dead'} />
-                      </td>
-                      <td>
-                        <MonoText size="sm" className={styles.instanceName}>{inst.name}</MonoText>
-                      </td>
-                      <td>
-                        <Badge
-                          label={inst.status.toUpperCase()}
-                          color={inst.status === 'live' ? 'success' : inst.status === 'stale' ? 'warning' : 'error'}
-                          variant="filled"
               />
-                      </td>
-                      <td>
-                        <MonoText size="xs" className={styles.instanceMeta}>{inst.uptime}</MonoText>
-                      </td>
-                      <td>
-                        <MonoText size="xs" className={styles.instanceMeta}>{inst.tps.toFixed(1)}/s</MonoText>
-                      </td>
-                      <td>
-                        <MonoText size="xs" className={inst.errorRate ? styles.instanceError : styles.instanceMeta}>
-                          {inst.errorRate ?? '0 err/h'}
-                        </MonoText>
-                      </td>
-                      <td>
-                        <MonoText size="xs" className={
-                          inst.status === 'dead' ? styles.instanceHeartbeatDead :
-                          inst.status === 'stale' ? styles.instanceHeartbeatStale :
-                          styles.instanceMeta
-                        }>
-                          {inst.lastSeen}
-                        </MonoText>
-                      </td>
-                    </tr>
-                  ))}
-                </tbody>
-              </table>
             </GroupCard>
           ))}
         </div>

src/pages/Inventory/Inventory.tsx

@@ -39,6 +39,7 @@ const NAV_SECTIONS = [
       { label: 'Spinner', href: '#spinner' },
       { label: 'StatCard', href: '#statcard' },
       { label: 'StatusDot', href: '#statusdot' },
+      { label: 'StatusText', href: '#statustext' },
       { label: 'Tag', href: '#tag' },
       { label: 'Textarea', href: '#textarea' },
       { label: 'Toggle', href: '#toggle' },
@@ -60,12 +61,15 @@ const NAV_SECTIONS = [
       { label: 'DataTable', href: '#datatable' },
       { label: 'DetailPanel', href: '#detailpanel' },
       { label: 'Dropdown', href: '#dropdown' },
+      { label: 'EntityList', href: '#entitylist' },
       { label: 'EventFeed', href: '#eventfeed' },
       { label: 'FilterBar', href: '#filterbar' },
       { label: 'GroupCard', href: '#groupcard' },
+      { label: 'KpiStrip', href: '#kpistrip' },
       { label: 'LineChart', href: '#linechart' },
       { label: 'LoginDialog', href: '#logindialog' },
       { label: 'LoginForm', href: '#loginform' },
+      { label: 'LogViewer', href: '#logviewer' },
       { label: 'MenuItem', href: '#menuitem' },
       { label: 'Modal', href: '#modal' },
       { label: 'MultiSelect', href: '#multi-select' },
@@ -74,6 +78,7 @@ const NAV_SECTIONS = [
       { label: 'RouteFlow', href: '#routeflow' },
       { label: 'SegmentedTabs', href: '#segmented-tabs' },
       { label: 'ShortcutsBar', href: '#shortcutsbar' },
+      { label: 'SplitPane', href: '#splitpane' },
       { label: 'Tabs', href: '#tabs' },
       { label: 'Toast', href: '#toast' },
       { label: 'TreeView', href: '#treeview' },

src/pages/Inventory/sections/CompositesSection.tsx

@@ -12,12 +12,15 @@ import {
   DataTable,
   DetailPanel,
   Dropdown,
+  EntityList,
   EventFeed,
   FilterBar,
   GroupCard,
+  KpiStrip,
   LineChart,
   LoginDialog,
   LoginForm,
+  LogViewer,
   MenuItem,
   Modal,
   MultiSelect,
@@ -26,13 +29,14 @@ import {
   RouteFlow,
   SegmentedTabs,
   ShortcutsBar,
+  SplitPane,
   Tabs,
   ToastProvider,
   useToast,
   TreeView,
 } from '../../../design-system/composites'
 import type { SearchResult } from '../../../design-system/composites'
-import { Button } from '../../../design-system/primitives'
+import { Avatar, Badge, Button } from '../../../design-system/primitives'
 
 // ── DemoCard helper ──────────────────────────────────────────────────────────
 
@@ -178,6 +182,60 @@ const TREE_NODES = [
   },
 ]
 
+// ── Sample data for new composites ───────────────────────────────────────────
+
+const KPI_ITEMS = [
+  {
+    label: 'Exchanges',
+    value: '12,847',
+    trend: { label: '\u2191 +8.2%', variant: 'success' as const },
+    subtitle: 'Last 24h',
+    sparkline: [40, 55, 48, 62, 70, 65, 78],
+    borderColor: 'var(--amber)',
+  },
+  {
+    label: 'Error Rate',
+    value: '0.34%',
+    trend: { label: '\u2191 +0.12pp', variant: 'error' as const },
+    subtitle: 'Above threshold',
+    sparkline: [10, 12, 11, 15, 18, 22, 19],
+    borderColor: 'var(--error)',
+  },
+  {
+    label: 'Avg Latency',
+    value: '142ms',
+    trend: { label: '\u2193 -12ms', variant: 'success' as const },
+    subtitle: 'P95: 380ms',
+    borderColor: 'var(--success)',
+  },
+  {
+    label: 'Active Routes',
+    value: '37',
+    trend: { label: '\u00b10', variant: 'muted' as const },
+    subtitle: '3 paused',
+    borderColor: 'var(--running)',
+  },
+]
+
+const ENTITY_LIST_ITEMS = [
+  { id: '1', name: 'Alice Johnson', email: 'alice@example.com', role: 'Admin' },
+  { id: '2', name: 'Bob Chen', email: 'bob@example.com', role: 'Editor' },
+  { id: '3', name: 'Carol Smith', email: 'carol@example.com', role: 'Viewer' },
+  { id: '4', name: 'David Park', email: 'david@example.com', role: 'Editor' },
+  { id: '5', name: 'Eva Martinez', email: 'eva@example.com', role: 'Admin' },
+]
+
+const LOG_ENTRIES = [
+  { timestamp: '2026-03-24T10:00:01Z', level: 'info' as const, message: 'Route timer-aggregator started successfully' },
+  { timestamp: '2026-03-24T10:00:03Z', level: 'debug' as const, message: 'Polling endpoint https://api.internal/health \u2014 200 OK' },
+  { timestamp: '2026-03-24T10:00:15Z', level: 'warn' as const, message: 'Retry queue depth at 847 \u2014 approaching threshold (1000)' },
+  { timestamp: '2026-03-24T10:00:22Z', level: 'error' as const, message: 'Exchange failed: Connection refused to jdbc:postgresql://db-primary:5432/orders' },
+  { timestamp: '2026-03-24T10:00:23Z', level: 'info' as const, message: 'Failover activated \u2014 routing to db-secondary' },
+  { timestamp: '2026-03-24T10:00:30Z', level: 'info' as const, message: 'Exchange completed in 142ms via fallback route' },
+  { timestamp: '2026-03-24T10:00:45Z', level: 'debug' as const, message: 'Metrics flush: 328 data points written to InfluxDB' },
+  { timestamp: '2026-03-24T10:01:00Z', level: 'warn' as const, message: 'Memory usage at 78% \u2014 GC scheduled' },
+]
+
 // ── CompositesSection ─────────────────────────────────────────────────────────
 
 export function CompositesSection() {
@@ -221,6 +279,10 @@ export function CompositesSection() {
   // MultiSelect
   const [multiValue, setMultiValue] = useState<string[]>(['admin'])
 
+  // EntityList state
+  const [selectedEntityId, setSelectedEntityId] = useState<string | undefined>('1')
+  const [entitySearch, setEntitySearch] = useState('')
+
   // LoginDialog
   const [loginDialogOpen, setLoginDialogOpen] = useState(false)
   const [loginLoading, setLoginLoading] = useState(false)
@@ -465,6 +527,38 @@ export function CompositesSection() {
           </div>
         </DemoCard>
 
+        {/* EntityList */}
+        <DemoCard
+          id="entitylist"
+          title="EntityList"
+          description="Searchable, selectable entity list with add button — designed to pair with SplitPane."
+        >
+          <div style={{ width: '100%', height: 260 }}>
+            <EntityList
+              items={ENTITY_LIST_ITEMS.filter(u =>
+                u.name.toLowerCase().includes(entitySearch.toLowerCase())
+              )}
+              renderItem={(item, isSelected) => (
+                <div style={{ display: 'flex', alignItems: 'center', gap: 10 }}>
+                  <Avatar name={item.name} size="sm" />
+                  <div>
+                    <div style={{ fontSize: 13, fontWeight: isSelected ? 600 : 400 }}>{item.name}</div>
+                    <div style={{ fontSize: 11, color: 'var(--text-muted)' }}>{item.email}</div>
+                  </div>
+                  <span style={{ marginLeft: 'auto' }}><Badge label={item.role} /></span>
+                </div>
+              )}
+              getItemId={(item) => item.id}
+              selectedId={selectedEntityId}
+              onSelect={setSelectedEntityId}
+              searchPlaceholder="Search users..."
+              onSearch={setEntitySearch}
+              addLabel="+ Add user"
+              onAdd={() => {}}
+            />
+          </div>
+        </DemoCard>
+
         {/* 11b. GroupCard */}
         <DemoCard
           id="groupcard"
@@ -484,6 +578,17 @@ export function CompositesSection() {
           </div>
         </DemoCard>
 
+        {/* KpiStrip */}
+        <DemoCard
+          id="kpistrip"
+          title="KpiStrip"
+          description="Horizontal row of KPI cards with coloured left border, trend indicator, subtitle, and optional sparkline."
+        >
+          <div style={{ width: '100%' }}>
+            <KpiStrip items={KPI_ITEMS} />
+          </div>
+        </DemoCard>
+
         {/* 12. FilterBar */}
         <DemoCard
           id="filterbar"
@@ -562,6 +667,17 @@ export function CompositesSection() {
           </div>
         </DemoCard>
 
+        {/* LogViewer */}
+        <DemoCard
+          id="logviewer"
+          title="LogViewer"
+          description="Scrollable log output with timestamped, severity-coloured monospace entries and auto-scroll."
+        >
+          <div style={{ width: '100%' }}>
+            <LogViewer entries={LOG_ENTRIES} maxHeight={240} />
+          </div>
+        </DemoCard>
+
         {/* 14. MenuItem */}
         <DemoCard
           id="menuitem"
@@ -707,6 +823,33 @@ export function CompositesSection() {
           />
         </DemoCard>
 
+        {/* SplitPane */}
+        <DemoCard
+          id="splitpane"
+          title="SplitPane"
+          description="Two-column master/detail layout with configurable ratio and empty-state placeholder."
+        >
+          <div style={{ width: '100%', height: 200 }}>
+            <SplitPane
+              list={
+                <div style={{ padding: 16, fontSize: 13 }}>
+                  <div style={{ fontWeight: 600, marginBottom: 8 }}>Items</div>
+                  <div>Item A</div>
+                  <div>Item B</div>
+                  <div>Item C</div>
+                </div>
+              }
+              detail={
+                <div style={{ padding: 16, fontSize: 13 }}>
+                  <div style={{ fontWeight: 600, marginBottom: 8 }}>Detail View</div>
+                  <div>Select an item on the left to see its details here.</div>
+                </div>
+              }
+              ratio="1:2"
+            />
+          </div>
+        </DemoCard>
+
         {/* 19. Tabs */}
         <DemoCard
           id="tabs"

src/pages/Inventory/sections/PrimitivesSection.tsx

@@ -32,6 +32,7 @@ import {
   Spinner,
   StatCard,
   StatusDot,
+  StatusText,
   Tag,
   Textarea,
   Toggle,
@@ -204,12 +205,18 @@ export function PrimitivesSection() {
       <DemoCard
         id="card"
         title="Card"
-        description="Surface container with optional left-border accent colour."
+        description="Surface container with optional left-border accent colour and title header."
       >
         <Card><div style={{ padding: '8px 12px', fontSize: 13 }}>Plain card</div></Card>
         <Card accent="amber"><div style={{ padding: '8px 12px', fontSize: 13 }}>Amber accent</div></Card>
         <Card accent="success"><div style={{ padding: '8px 12px', fontSize: 13 }}>Success accent</div></Card>
         <Card accent="error"><div style={{ padding: '8px 12px', fontSize: 13 }}>Error accent</div></Card>
+        <Card title="Throughput (msg/s)">
+          <div style={{ padding: '8px 12px', fontSize: 13 }}>Card with title header and separator</div>
+        </Card>
+        <Card accent="amber" title="Error Rate">
+          <div style={{ padding: '8px 12px', fontSize: 13 }}>Title + accent combined</div>
+        </Card>
       </DemoCard>
 
       {/* 6. Checkbox */}
@@ -559,7 +566,31 @@ export function PrimitivesSection() {
         </div>
       </DemoCard>
 
-      {/* 29. Tag */}
+      {/* 29. StatusText */}
+      <DemoCard
+        id="statustext"
+        title="StatusText"
+        description="Inline coloured text for status values — five semantic variants with optional bold."
+      >
+        <div className={styles.demoAreaColumn} style={{ width: '100%' }}>
+          <div className={styles.demoAreaRow}>
+            <StatusText variant="success">99.8% uptime</StatusText>
+            <StatusText variant="warning">SLA at risk</StatusText>
+            <StatusText variant="error">BREACH</StatusText>
+            <StatusText variant="running">Processing</StatusText>
+            <StatusText variant="muted">N/A</StatusText>
+          </div>
+          <div className={styles.demoAreaRow}>
+            <StatusText variant="success" bold>99.8% uptime</StatusText>
+            <StatusText variant="warning" bold>SLA at risk</StatusText>
+            <StatusText variant="error" bold>BREACH</StatusText>
+            <StatusText variant="running" bold>Processing</StatusText>
+            <StatusText variant="muted" bold>N/A</StatusText>
+          </div>
+        </div>
+      </DemoCard>
+
+      {/* 30. Tag */}
       <DemoCard
         id="tag"
         title="Tag"
@@ -573,7 +604,7 @@ export function PrimitivesSection() {
         <Tag label="removable" color="primary" onRemove={() => undefined} />
       </DemoCard>
 
-      {/* 30. Textarea */}
+      {/* 31. Textarea */}
       <DemoCard
         id="textarea"
         title="Textarea"
@@ -582,7 +613,7 @@ export function PrimitivesSection() {
         <Textarea placeholder="Enter a description…" style={{ width: 280 }} />
       </DemoCard>
 
-      {/* 31. Toggle */}
+      {/* 32. Toggle */}
       <DemoCard
         id="toggle"
         title="Toggle"
@@ -602,7 +633,7 @@ export function PrimitivesSection() {
         <Toggle label="Locked off" disabled />
       </DemoCard>
 
-      {/* 32. Tooltip */}
+      {/* 33. Tooltip */}
       <DemoCard
         id="tooltip"
         title="Tooltip"