diff --git a/src/web/public/app.js b/src/web/public/app.js
index c63f12be..169bfb19 100644
--- a/src/web/public/app.js
+++ b/src/web/public/app.js
@@ -2358,34 +2358,68 @@ class CodemanApp {
     const text = this.$('connectionText');
     if (!indicator || !dot || !text) return;
 
-    const status = this._connectionStatus;
+    const { bytes: totalBytes, count } = this._pendingBytes();
+    const hasQueue = count > 0;
+    // Only surface a backlog once it's more than a few bytes. A single keystroke
+    // (1B) ACKs in milliseconds, so without this the label flickered "sending 1B"
+    // on every key press. Above this threshold means input is genuinely backing up.
+    const BACKLOG_HINT_BYTES = 4;
+    const showBacklog = totalBytes > BACKLOG_HINT_BYTES;
+    const formatBytes = (b) => (b < 1024 ? `${b}B` : `${(b / 1024).toFixed(1)}KB`);
+    const queuedSuffix = showBacklog ? ` · ${formatBytes(totalBytes)} queued` : '';
 
-    // While the connection is healthy, never surface the input queue. With the
-    // reliable-delivery layer every keystroke is briefly "pending" until its ACK
-    // lands a few ms later — showing that flashed "Sending 1B…" on every single
-    // character. The indicator is only meaningful for an actual connection
-    // problem (reconnecting / offline), where the queued byte count reassures
-    // the user their typing is safely buffered and will be sent.
-    if (status === 'connected' || status === 'connecting') {
-      indicator.style.display = 'none';
+    // Hard offline (browser reports no network) dominates everything.
+    if (!this.isOnline || this._connectionStatus === 'offline') {
+      indicator.style.display = 'flex';
+      dot.className = 'connection-dot offline';
+      text.textContent = showBacklog ? `Offline (${formatBytes(totalBytes)} queued)` : 'Offline';
+      indicator.title = 'No network connection';
       return;
     }
 
-    const { bytes: totalBytes, count } = this._pendingBytes();
-    const hasQueue = count > 0;
-    indicator.style.display = 'flex';
-    dot.className = 'connection-dot';
-
-    const formatBytes = (b) => (b < 1024 ? `${b}B` : `${(b / 1024).toFixed(1)}KB`);
-
-    if (status === 'reconnecting') {
-      dot.classList.add('reconnecting');
-      text.textContent = hasQueue ? `Reconnecting (${formatBytes(totalBytes)} queued)` : 'Reconnecting...';
-    } else {
-      // Offline or disconnected
-      dot.classList.add('offline');
-      text.textContent = hasQueue ? `Offline (${formatBytes(totalBytes)} queued)` : 'Offline';
+    // With an active terminal, show its transport (WebSocket vs HTTP fallback).
+    if (this.activeSessionId) {
+      let cls, label, detail;
+      switch (this._wsState) {
+        case 'connected':
+          cls = 'connected'; label = 'WS'; detail = 'Terminal connected over WebSocket';
+          break;
+        case 'fallback':
+          cls = 'fallback'; label = 'HTTP'; detail = 'WebSocket unavailable — input sent over HTTP';
+          break;
+        case 'reconnecting':
+          cls = 'reconnecting'; label = 'WS…'; detail = 'Reconnecting WebSocket';
+          break;
+        case 'connecting':
+        default:
+          cls = 'reconnecting'; label = 'WS…'; detail = 'Connecting WebSocket';
+          break;
+      }
+      indicator.style.display = 'flex';
+      dot.className = `connection-dot ${cls}`;
+      text.textContent = `${label}${queuedSuffix}`;
+      indicator.title = detail;
+      return;
     }
+
+    // No active terminal — reflect the SSE event stream only when it needs attention.
+    if (this._connectionStatus === 'reconnecting' || this._connectionStatus === 'disconnected') {
+      indicator.style.display = 'flex';
+      dot.className = 'connection-dot reconnecting';
+      text.textContent = showBacklog ? `Reconnecting (${formatBytes(totalBytes)} queued)` : 'Reconnecting...';
+      indicator.title = 'Reconnecting to server';
+      return;
+    }
+
+    // Idle dashboard, healthy stream — hide unless input is genuinely queued.
+    if (!hasQueue) {
+      indicator.style.display = 'none';
+      return;
+    }
+    indicator.style.display = 'flex';
+    dot.className = 'connection-dot draining';
+    text.textContent = showBacklog ? `Sending ${formatBytes(totalBytes)}...` : 'Sending...';
+    indicator.title = 'Delivering queued input';
   }
 
   setupOnlineDetection() {
diff --git a/test/connection-indicator.test.ts b/test/connection-indicator.test.ts
new file mode 100644
index 00000000..3f8bcc66
--- /dev/null
+++ b/test/connection-indicator.test.ts
@@ -0,0 +1,204 @@
+/**
+ * @fileoverview Regression tests for the header connection indicator
+ * (`CodemanApp._updateConnectionIndicator`) and the invariant that updating it
+ * never aborts durable input delivery.
+ *
+ * Guards two regressions from the upstream v1.1.15 merge (fixed in COD-133):
+ *   1. The indicator body referenced an undefined `transport` object, throwing
+ *      `ReferenceError: transport is not defined` on every queued state. Because
+ *      `_reliableSend()` calls `_updateConnectionIndicator()` *before*
+ *      `_drainSession()`, the throw skipped immediate delivery on every keystroke
+ *      → input only flushed on the 2s sweep (large typing lag) and the indicator
+ *      never rendered (missing "WS" status).
+ *   2. The restored body only read the SSE `_connectionStatus`, so it never
+ *      surfaced the terminal WebSocket transport ("WS" / "HTTP"), and it flashed
+ *      "sending 1B" on every single keystroke.
+ *
+ * Loaded via `vm` with a stubbed context (no jsdom — see input-send-order.test.ts).
+ */
+import { readFileSync } from 'node:fs';
+import { performance } from 'node:perf_hooks';
+import { resolve } from 'node:path';
+import vm from 'node:vm';
+import { describe, expect, it, vi } from 'vitest';
+
+function loadCodemanAppClass() {
+  const constants = readFileSync(resolve(import.meta.dirname, '../src/web/public/constants.js'), 'utf8');
+  const source = readFileSync(resolve(import.meta.dirname, '../src/web/public/app.js'), 'utf8');
+  const context = vm.createContext({
+    console,
+    performance,
+    setInterval: vi.fn(),
+    clearInterval: vi.fn(),
+    setTimeout,
+    clearTimeout,
+    requestAnimationFrame: vi.fn(),
+    HTMLCanvasElement: class HTMLCanvasElement {},
+    fetch: (...args: Parameters<typeof fetch>) => global.fetch(...args),
+    document: { addEventListener: vi.fn() },
+    localStorage: {
+      length: 0,
+      key: vi.fn(),
+      getItem: vi.fn(),
+      setItem: vi.fn(),
+      removeItem: vi.fn(),
+    },
+    window: { addEventListener: vi.fn(), removeEventListener: vi.fn() },
+    MobileDetection: {},
+  });
+  vm.runInContext(`${constants}\n${source}\nglobalThis.__CodemanApp = CodemanApp;`, context);
+  return (context as { __CodemanApp: new () => unknown }).__CodemanApp;
+}
+
+const CodemanApp = loadCodemanAppClass();
+
+function fakeElement() {
+  return { style: { display: '' }, title: '', textContent: '', className: '' };
+}
+
+type Indicator = {
+  $: (id: string) => unknown;
+  _pendingDeliveries: Map<string, Array<{ seq: number; data: string }>>;
+  _connectionStatus: string;
+  _wsState: string;
+  activeSessionId: string | null;
+  isOnline: boolean;
+  _updateConnectionIndicator: () => void;
+};
+
+function makeApp(overrides: Partial<Indicator> & { queuedBytes?: number } = {}) {
+  const app = Object.create((CodemanApp as { prototype: object }).prototype) as Indicator & {
+    queuedBytes?: number;
+  };
+  const els: Record<string, ReturnType<typeof fakeElement>> = {
+    connectionIndicator: fakeElement(),
+    connectionDot: fakeElement(),
+    connectionText: fakeElement(),
+  };
+  app.$ = (id: string) => els[id];
+  app._pendingDeliveries = new Map();
+  app._connectionStatus = 'connected';
+  app._wsState = 'disconnected';
+  app.activeSessionId = null;
+  app.isOnline = true;
+  Object.assign(app, overrides);
+  const queued = overrides.queuedBytes ?? 0;
+  if (queued > 0) {
+    app._pendingDeliveries.set('s1', [{ seq: 1, data: 'x'.repeat(queued) }]);
+  }
+  return { app, els };
+}
+
+describe('connection indicator — transport display', () => {
+  it('shows "WS" with a connected dot when the terminal WebSocket is open', () => {
+    const { app, els } = makeApp({ activeSessionId: 's1', _wsState: 'connected' });
+    app._updateConnectionIndicator();
+    expect(els.connectionIndicator.style.display).toBe('flex');
+    expect(els.connectionText.textContent).toBe('WS');
+    expect(els.connectionDot.className).toContain('connected');
+  });
+
+  it('shows "HTTP" with a fallback dot when the socket dropped to HTTP POST', () => {
+    const { app, els } = makeApp({ activeSessionId: 's1', _wsState: 'fallback' });
+    app._updateConnectionIndicator();
+    expect(els.connectionText.textContent).toBe('HTTP');
+    expect(els.connectionDot.className).toContain('fallback');
+  });
+
+  it('shows "WS…" while connecting or reconnecting the socket', () => {
+    for (const state of ['connecting', 'reconnecting']) {
+      const { app, els } = makeApp({ activeSessionId: 's1', _wsState: state });
+      app._updateConnectionIndicator();
+      expect(els.connectionText.textContent).toBe('WS…');
+      expect(els.connectionDot.className).toContain('reconnecting');
+    }
+  });
+
+  it('shows "Offline" when the browser reports no network', () => {
+    const { app, els } = makeApp({ activeSessionId: 's1', _wsState: 'connected', isOnline: false });
+    app._updateConnectionIndicator();
+    expect(els.connectionText.textContent).toBe('Offline');
+    expect(els.connectionDot.className).toContain('offline');
+  });
+
+  it('hides on an idle dashboard (no active session, healthy stream, no queue)', () => {
+    const { app, els } = makeApp({ activeSessionId: null, _connectionStatus: 'connected' });
+    app._updateConnectionIndicator();
+    expect(els.connectionIndicator.style.display).toBe('none');
+  });
+
+  it('surfaces SSE reconnecting on the dashboard when there is no active terminal', () => {
+    const { app, els } = makeApp({ activeSessionId: null, _connectionStatus: 'reconnecting' });
+    app._updateConnectionIndicator();
+    expect(els.connectionText.textContent).toContain('Reconnecting');
+    expect(els.connectionDot.className).toContain('reconnecting');
+  });
+});
+
+describe('connection indicator — keystroke backlog threshold', () => {
+  it('does NOT annotate a single-keystroke (1B) queue — no "sending 1B" flicker', () => {
+    const { app, els } = makeApp({ activeSessionId: 's1', _wsState: 'connected', queuedBytes: 1 });
+    app._updateConnectionIndicator();
+    expect(els.connectionText.textContent).toBe('WS');
+    expect(els.connectionText.textContent).not.toMatch(/queued/);
+  });
+
+  it('does NOT annotate at the 4B threshold boundary', () => {
+    const { app, els } = makeApp({ activeSessionId: 's1', _wsState: 'connected', queuedBytes: 4 });
+    app._updateConnectionIndicator();
+    expect(els.connectionText.textContent).toBe('WS');
+  });
+
+  it('annotates a genuine backlog (>4B) with a queued byte count', () => {
+    const { app, els } = makeApp({ activeSessionId: 's1', _wsState: 'connected', queuedBytes: 40 });
+    app._updateConnectionIndicator();
+    expect(els.connectionText.textContent).toMatch(/^WS · 40B queued$/);
+  });
+});
+
+describe('connection indicator — never throws (the ReferenceError regression)', () => {
+  it('renders every transport × stream × queue combination without throwing', () => {
+    const wsStates = ['disconnected', 'connecting', 'connected', 'reconnecting', 'fallback'];
+    const sseStates = ['connected', 'connecting', 'reconnecting', 'disconnected', 'offline'];
+    for (const ws of wsStates) {
+      for (const sse of sseStates) {
+        for (const active of ['s1', null] as const) {
+          for (const queuedBytes of [0, 1, 4, 200]) {
+            for (const isOnline of [true, false]) {
+              const { app } = makeApp({
+                activeSessionId: active,
+                _wsState: ws,
+                _connectionStatus: sse,
+                isOnline,
+                queuedBytes,
+              });
+              expect(() => app._updateConnectionIndicator()).not.toThrow();
+            }
+          }
+        }
+      }
+    }
+  });
+});
+
+describe('durable input delivery is not aborted by the indicator (typing-lag regression)', () => {
+  it('_reliableSend reaches _drainSession after updating the indicator', () => {
+    const { app } = makeApp({ activeSessionId: 's1', _wsState: 'connected' });
+    const a = app as unknown as {
+      _seqCounters: Map<string, number>;
+      _persistReliableState: () => void;
+      _drainSession: (id: string) => void;
+      _reliableSend: (id: string, data: string, useMux: boolean) => void;
+    };
+    a._seqCounters = new Map();
+    a._persistReliableState = vi.fn();
+    const drain = vi.fn();
+    a._drainSession = drain;
+
+    // A single keystroke. The indicator runs first; if it throws, drain is skipped.
+    a._reliableSend('s1', 'x', false);
+
+    expect(drain).toHaveBeenCalledWith('s1');
+    expect(app._pendingDeliveries.get('s1')).toHaveLength(1);
+  });
+});
diff --git a/test/input-send-order.test.ts b/test/input-send-order.test.ts
new file mode 100644
index 00000000..cc7c6294
--- /dev/null
+++ b/test/input-send-order.test.ts
@@ -0,0 +1,159 @@
+/**
+ * @fileoverview Input dispatch ordering for the durable, acknowledged delivery
+ * layer (`CodemanApp._sendInputAsync` → `_reliableSend` → `_drainSession`).
+ *
+ * Local replaced the upstream best-effort "coalescing fallback queue" with the
+ * durable per-(clientId, seq) layer in commit 1255e28 (docs/reliable-input-
+ * delivery.md). This suite verifies the client-side ordering guarantees of that
+ * layer: each input is a distinct seq-tagged frame, delivered in order over the
+ * WebSocket when open, serialized over HTTP POST when not, and only dropped on a
+ * server ACK (HTTP 2xx). Exactly-once application is covered server-side in
+ * test/reliable-input-dedup.test.ts; the header transport indicator ("WS"/"HTTP")
+ * is covered in test/connection-indicator.test.ts.
+ *
+ * Loaded via `vm` with a stubbed context (no jsdom).
+ */
+import { readFileSync } from 'node:fs';
+import { performance } from 'node:perf_hooks';
+import { resolve } from 'node:path';
+import vm from 'node:vm';
+import { describe, expect, it, vi } from 'vitest';
+
+function loadCodemanAppClass() {
+  const constants = readFileSync(resolve(import.meta.dirname, '../src/web/public/constants.js'), 'utf8');
+  const source = readFileSync(resolve(import.meta.dirname, '../src/web/public/app.js'), 'utf8');
+  const context = vm.createContext({
+    console,
+    performance,
+    setInterval: vi.fn(),
+    clearInterval: vi.fn(),
+    setTimeout,
+    clearTimeout,
+    requestAnimationFrame: vi.fn(),
+    HTMLCanvasElement: class HTMLCanvasElement {},
+    WebSocket: { OPEN: 1 },
+    fetch: (...args: Parameters<typeof fetch>) => global.fetch(...args),
+    document: { addEventListener: vi.fn() },
+    localStorage: {
+      length: 0,
+      key: vi.fn(),
+      getItem: vi.fn(),
+      setItem: vi.fn(),
+      removeItem: vi.fn(),
+    },
+    window: { addEventListener: vi.fn(), removeEventListener: vi.fn() },
+    MobileDetection: {},
+  });
+  vm.runInContext(`${constants}\n${source}\nglobalThis.__CodemanApp = CodemanApp;`, context);
+  return (context as { __CodemanApp: new () => unknown }).__CodemanApp;
+}
+
+const CodemanApp = loadCodemanAppClass();
+
+async function waitForCalls(calls: unknown[], count: number) {
+  for (let i = 0; i < 50; i++) {
+    if (calls.length >= count) return;
+    await new Promise((r) => setTimeout(r, 0));
+  }
+}
+
+type Frame = { t: string; d: string; seq: number; cid: string };
+type PostBody = { input: string; seq: number; clientId: string };
+
+type App = {
+  _sendInputAsync: (sessionId: string, input: string, opts?: { useMux?: boolean }) => void;
+  _pendingDeliveries: Map<string, Array<{ seq: number; data: string; sentAt: number }>>;
+  _ws: { readyState: number; send: (data: string) => void } | null;
+  _wsSessionId: string | null;
+  activeSessionId: string | null;
+};
+
+function makeApp(): App {
+  const app = Object.create((CodemanApp as { prototype: object }).prototype) as App & Record<string, unknown>;
+  app._clientId = 'c-test';
+  app._seqCounters = new Map();
+  app._pendingDeliveries = new Map();
+  app._postDraining = new Set();
+  app._persistReliableState = vi.fn();
+  app._persistReliableNow = vi.fn();
+  app._updateConnectionIndicator = vi.fn();
+  app.clearPendingHooks = vi.fn();
+  app.activeSessionId = 'session-1';
+  app.isOnline = true;
+  app._connectionStatus = 'connected';
+  app._ws = null;
+  app._wsSessionId = null;
+  return app as unknown as App;
+}
+
+describe('durable input delivery — send ordering', () => {
+  it('delivers rapid input as distinct ordered seq frames over an open WebSocket (no coalescing)', () => {
+    const app = makeApp();
+    const frames: Frame[] = [];
+    app._ws = { readyState: 1, send: (d: string) => frames.push(JSON.parse(d)) };
+    app._wsSessionId = 'session-1';
+
+    app._sendInputAsync('session-1', 'a');
+    app._sendInputAsync('session-1', 'b');
+    app._sendInputAsync('session-1', 'c');
+
+    // Each keystroke is its own frame, in seq order — never merged into "abc".
+    expect(frames.map((f) => f.d)).toEqual(['a', 'b', 'c']);
+    expect(frames.map((f) => f.seq)).toEqual([1, 2, 3]);
+    expect(frames.every((f) => f.t === 'i' && f.cid === 'c-test')).toBe(true);
+  });
+
+  it('POSTs queued input one frame at a time in seq order when no socket is open', async () => {
+    const app = makeApp();
+    const calls: PostBody[] = [];
+    const completions: Array<() => void> = [];
+    global.fetch = vi.fn(async (_url, init) => {
+      calls.push(JSON.parse(String(init?.body)) as PostBody);
+      await new Promise<void>((r) => completions.push(r));
+      return new Response('{}', { status: 200 });
+    });
+
+    app._sendInputAsync('session-1', 'a');
+    app._sendInputAsync('session-1', 'b');
+
+    // Serialized: only the first frame is in flight until its 2xx ACK lands.
+    await waitForCalls(calls, 1);
+    expect(calls.map((c) => c.input)).toEqual(['a']);
+
+    completions.shift()?.(); // ACK 'a'
+    await waitForCalls(calls, 2);
+    expect(calls.map((c) => c.input)).toEqual(['a', 'b']);
+    expect(calls.map((c) => c.seq)).toEqual([1, 2]);
+
+    completions.shift()?.();
+    await waitForCalls(calls, 2);
+  });
+
+  it('leaves a frame queued (unacked) when HTTP delivery fails', async () => {
+    const app = makeApp();
+    const calls: PostBody[] = [];
+    global.fetch = vi.fn(async (_url, init) => {
+      calls.push(JSON.parse(String(init?.body)) as PostBody);
+      return new Response('busy', { status: 503 });
+    });
+
+    app._sendInputAsync('session-1', 'a');
+    await waitForCalls(calls, 1);
+    await new Promise((r) => setTimeout(r, 0));
+
+    // 5xx is not an ACK — the frame must survive for the sweep/reconnect to retry.
+    expect(app._pendingDeliveries.get('session-1')).toHaveLength(1);
+    expect(app._pendingDeliveries.get('session-1')?.[0].data).toBe('a');
+  });
+
+  it('drops a frame addressed to a vanished session (404) instead of retrying forever', async () => {
+    const app = makeApp();
+    global.fetch = vi.fn(async () => new Response('gone', { status: 404 }));
+
+    app._sendInputAsync('session-1', 'a');
+    await new Promise((r) => setTimeout(r, 0));
+    await new Promise((r) => setTimeout(r, 0));
+
+    expect(app._pendingDeliveries.get('session-1')).toBeUndefined();
+  });
+});