diff --git a/web/src/canvas/Turn.tsx b/web/src/canvas/Turn.tsx
new file mode 100644
index 0000000..cdfe91f
--- /dev/null
+++ b/web/src/canvas/Turn.tsx
@@ -0,0 +1,124 @@
+import type { CSSProperties } from 'react';
+import type { ToolCall } from '@/api/types';
+import { Sidenote } from './Sidenote';
+
+interface TurnProps {
+  agent: string;
+  timestamp: string;  // ISO UTC
+  elapsedMs: number | null;
+  body: string;
+  confidence: number | null;
+  model: string;
+  durationMs: number;
+  turn: number;
+  toolCalls: ToolCall[];
+  active: boolean;
+  onSelectTool: (tc: ToolCall) => void;
+}
+
+const grid: CSSProperties = {
+  display: 'grid',
+  gridTemplateColumns: '96px 1fr 240px',
+  gap: 24,
+  padding: '16px 24px',
+  borderBottom: '1px solid var(--hair)',
+  transition: 'background-color 0.12s',
+};
+
+const bylineStyle: CSSProperties = {
+  display: 'flex',
+  flexDirection: 'column',
+  alignItems: 'flex-end',
+  gap: 2,
+  fontFamily: 'var(--ff-mono)',
+};
+
+function fmtTime(iso: string): string {
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return iso;
+  return d.toISOString().slice(11, 19);
+}
+
+function fmtElapsed(ms: number | null): string | null {
+  if (ms === null || ms === undefined) return null;
+  if (ms === 0) return '+0s';
+  const sec = ms / 1000;
+  if (sec < 60) return `+${sec.toFixed(1)}s`;
+  const m = Math.floor(sec / 60);
+  const s = Math.round(sec % 60);
+  return `+${m}m${s}s`;
+}
+
+export function Turn(props: TurnProps) {
+  const elapsedStr = fmtElapsed(props.elapsedMs);
+  return (
+    <div
+      data-turn={props.turn}
+      data-active={props.active}
+      style={{
+        ...grid,
+        background: 'transparent',
+      }}
+      onMouseEnter={(e) => {
+        e.currentTarget.style.background = 'var(--bg-tint)';
+      }}
+      onMouseLeave={(e) => {
+        e.currentTarget.style.background = 'transparent';
+      }}
+    >
+      <div style={bylineStyle}>
+        <span
+          style={{
+            fontSize: 12,
+            fontWeight: 500,
+            color: props.active ? 'var(--acc)' : 'var(--ink-1)',
+          }}
+        >
+          {props.agent}
+        </span>
+        <span style={{ fontSize: 10, color: 'var(--ink-3)' }}>
+          {fmtTime(props.timestamp)}
+        </span>
+        {elapsedStr && (
+          <span style={{ fontSize: 10, color: 'var(--ink-4)' }}>
+            {elapsedStr}
+          </span>
+        )}
+      </div>
+      <div
+        style={{
+          fontFamily: 'var(--ff-sans)',
+          fontSize: 14,
+          lineHeight: 1.6,
+          color: props.active ? 'var(--ink-2)' : 'var(--ink-1)',
+          fontStyle: props.active ? 'italic' : 'normal',
+        }}
+      >
+        {props.body}
+        {props.active && (
+          <span
+            data-typing-cursor
+            aria-hidden
+            style={{
+              display: 'inline-block',
+              width: 7,
+              height: 14,
+              marginLeft: 4,
+              verticalAlign: -2,
+              background: 'var(--ink-2)',
+              animation: 'asr-typing 1.2s step-end infinite',
+            }}
+          />
+        )}
+      </div>
+      <Sidenote
+        confidence={props.confidence}
+        model={props.model}
+        durationMs={props.durationMs}
+        turn={props.turn}
+        toolCalls={props.toolCalls}
+        onSelectTool={props.onSelectTool}
+      />
+    </div>
+  );
+}
diff --git a/web/src/styles/global.css b/web/src/styles/global.css
index d2777e2..7a7e5d4 100644
--- a/web/src/styles/global.css
+++ b/web/src/styles/global.css
@@ -99,3 +99,8 @@ body {
   0%, 100% { opacity: 1; }
   50% { opacity: 0.4; }
 }
+
+@keyframes asr-typing {
+  0%, 50% { opacity: 1; }
+  51%, 100% { opacity: 0; }
+}
diff --git a/web/tests/component/Turn.test.tsx b/web/tests/component/Turn.test.tsx
new file mode 100644
index 0000000..8de716b
--- /dev/null
+++ b/web/tests/component/Turn.test.tsx
@@ -0,0 +1,100 @@
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen } from '../_helpers/render';
+import { Turn } from '@/canvas/Turn';
+import type { ToolCall } from '@/api/types';
+
+const tools: ToolCall[] = [];
+
+describe('<Turn>', () => {
+  it('renders byline with agent name + timestamp', () => {
+    render(
+      <Turn
+        agent="intake" timestamp="2026-05-15T14:16:32Z" elapsedMs={2200}
+        body="Triage observed elevated p99 latency on payments-svc."
+        confidence={0.92} model="gpt" durationMs={1230} turn={1}
+        toolCalls={tools}
+        active={false}
+        onSelectTool={() => {}}
+      />,
+    );
+    expect(screen.getByText('intake')).toBeInTheDocument();
+    expect(screen.getByText(/14:16:32/)).toBeInTheDocument();
+    expect(screen.getByText(/Triage observed/)).toBeInTheDocument();
+  });
+
+  it('renders elapsed delta in mono when provided', () => {
+    render(
+      <Turn
+        agent="x" timestamp="2026-05-15T14:16:32Z" elapsedMs={2200}
+        body="x" confidence={null} model="x" durationMs={0} turn={1}
+        toolCalls={tools} active={false}
+        onSelectTool={() => {}}
+      />,
+    );
+    expect(screen.getByText(/\+2\.2s/)).toBeInTheDocument();
+  });
+
+  it('marks active turn with data-active="true" and shows typing cursor in body', () => {
+    const { container } = render(
+      <Turn
+        agent="investigate" timestamp="2026-05-15T14:17:30Z" elapsedMs={null}
+        body="Reading deploy diff..." confidence={null} model="x" durationMs={0} turn={2}
+        toolCalls={tools} active={true}
+        onSelectTool={() => {}}
+      />,
+    );
+    expect(container.firstChild).toHaveAttribute('data-active', 'true');
+    expect(container.querySelector('[data-typing-cursor]')).not.toBeNull();
+  });
+
+  it('non-active turn omits typing cursor', () => {
+    const { container } = render(
+      <Turn
+        agent="x" timestamp="2026-05-15T14:16:00Z" elapsedMs={0}
+        body="done" confidence={null} model="x" durationMs={0} turn={1}
+        toolCalls={tools} active={false}
+        onSelectTool={() => {}}
+      />,
+    );
+    expect(container.querySelector('[data-typing-cursor]')).toBeNull();
+    expect(container.firstChild).toHaveAttribute('data-active', 'false');
+  });
+
+  it('passes toolCalls through to Sidenote and renders them', () => {
+    const tc: ToolCall = {
+      agent: 'x', tool: 'obs:get_logs', args: {}, result: null,
+      ts: '2026-05-15T14:16:50Z', risk: 'low',
+      status: 'executed', approver: null, approved_at: null, approval_rationale: null,
+    };
+    render(
+      <Turn
+        agent="x" timestamp="2026-05-15T14:16:32Z" elapsedMs={0}
+        body="x" confidence={null} model="x" durationMs={0} turn={1}
+        toolCalls={[tc]} active={false}
+        onSelectTool={() => {}}
+      />,
+    );
+    expect(screen.getByText('obs:get_logs')).toBeInTheDocument();
+  });
+
+  it('forwards onSelectTool to Sidenote', () => {
+    const onSelectTool = vi.fn();
+    const tc: ToolCall = {
+      agent: 'x', tool: 'obs:get_logs', args: {}, result: null,
+      ts: 'x', risk: null, status: 'executed',
+      approver: null, approved_at: null, approval_rationale: null,
+    };
+    render(
+      <Turn
+        agent="x" timestamp="2026-05-15T14:16:32Z" elapsedMs={0}
+        body="x" confidence={null} model="x" durationMs={0} turn={1}
+        toolCalls={[tc]} active={false}
+        onSelectTool={onSelectTool}
+      />,
+    );
+    screen.getByText('obs:get_logs').closest('[data-tool-card]')!.dispatchEvent(
+      new MouseEvent('click', { bubbles: true }),
+    );
+    expect(onSelectTool).toHaveBeenCalledWith(tc);
+  });
+});