diff --git a/electron/native/fn-watcher.swift b/electron/native/fn-watcher.swift
index b7ba2c2b..da575bf2 100644
--- a/electron/native/fn-watcher.swift
+++ b/electron/native/fn-watcher.swift
@@ -3,6 +3,16 @@
 // tap: needs the same Input Monitoring grant the app already requests, never swallows anything.
 import CoreGraphics
 import Foundation
+import IOKit.hid
+
+// --no-prompt: the boot-time probe must never raise the Input Monitoring TCC prompt (ENG-341);
+// IOHIDCheckAccess answers silently, so granted machines arm and everyone else exits clean.
+if CommandLine.arguments.contains("--no-prompt")
+    && IOHIDCheckAccess(kIOHIDRequestTypeListenEvent) != kIOHIDAccessTypeGranted {
+    print("e no-permission")
+    fflush(stdout)
+    exit(0)
+}
 
 var fnDown = false
 var tapRef: CFMachPort?
diff --git a/electron/voiceHotkey.js b/electron/voiceHotkey.js
index 7bde5108..fd6e23b3 100644
--- a/electron/voiceHotkey.js
+++ b/electron/voiceHotkey.js
@@ -139,12 +139,12 @@ function installVoiceHotkey(getMainWindow) {
   // ---- fn/Globe primary tier (macOS): the native watcher, since no JS tap can see keycode 63 ----
   let fnProc = null;
   let quitReaperWired = false;
-  const startFnWatcher = () => {
+  const startFnWatcher = (noPrompt) => {
     if (process.platform !== 'darwin' || combo.special !== 'fn' || fnProc) return;
     resolveFnWatcherBinary((bin) => {
       if (!bin) { console.log('[voice] no fn watcher binary, legacy hotkey stays primary'); return; }
       if (combo.special !== 'fn' || fnProc) return; // rebound or raced while compiling
-      startFnWatcherWith(bin);
+      startFnWatcherWith(bin, noPrompt === true);
     });
   };
   // Kill fn-watchers left by a previous OpenSwarm that died badly. will-quit is the ONLY thing that
@@ -170,11 +170,11 @@ function installVoiceHotkey(getMainWindow) {
     lastFnPokeMs = now;
     try { fnProc.stdin.write('r\n'); } catch (_) {}
   };
-  const startFnWatcherWith = (bin) => {
+  const startFnWatcherWith = (bin, noPrompt) => {
     sweepStrayFnWatchers(bin);
     try {
       // stdin stays open on purpose: "r\n" re-arms the tap, and EOF tells an orphaned watcher to die.
-      fnProc = spawn(bin, [], { stdio: ['pipe', 'pipe', 'ignore'] });
+      fnProc = spawn(bin, noPrompt ? ['--no-prompt'] : [], { stdio: ['pipe', 'pipe', 'ignore'] });
     } catch (e) {
       console.log('[voice] fn watcher spawn failed:', e && e.message);
       fnProc = null;
@@ -304,6 +304,10 @@ function installVoiceHotkey(getMainWindow) {
   };
   try {
     if (fs.existsSync(path.join(app.getPath('userData'), 'dictation-used'))) armNativeTiers();
+    // No marker yet: fn is the DEFAULT hotkey, and the watcher is the only thing that can see it,
+    // so probe it in --no-prompt mode. Machines with Input Monitoring already granted get a working
+    // fn immediately; ungranted machines exit silently and never see a boot-time TCC prompt (ENG-341).
+    else if (combo.special === 'fn') startFnWatcher(true);
   } catch (_) {}
   app.on('browser-window-focus', () => { unregisterFallbackShortcut(); pokeFnWatcher(); });
   app.on('browser-window-blur', registerVoiceShortcut);
@@ -326,6 +330,14 @@ function installVoiceHotkey(getMainWindow) {
   const installVoiceHoldRelay = (contents) => {
     contents.on('before-input-event', (event, input) => {
       if (input.type !== 'keyDown' || input.isAutoRepeat) return;
+      // A bare Fn keydown Chromium happens to deliver while focused is both dictation intent
+      // (full-arm the tiers, prompt lands with context) and a press that must WORK right now.
+      if (combo.special === 'fn' && !primaryProven() && (input.key === 'Fn' || input.code === 'Fn')) {
+        armNativeTiers();
+        sendFallbackToggle();
+        event.preventDefault();
+        return;
+      }
       if (inputMatchesCombo(input)) {
         if (!primaryProven()) sendFallbackToggle();
         event.preventDefault();
@@ -347,6 +359,7 @@ function installVoiceHotkey(getMainWindow) {
     fallbackCombo = combo.special ? parseCombo(LEGACY_COMBO) : combo;
     if (UiohookKeyRef && !combo.special) tapKeycode = uiohookKeycodeFor(combo.key, UiohookKeyRef);
     if (tiersArmed) startFnWatcher();
+    else if (combo.special === 'fn') startFnWatcher(true);
     unregisterFallbackShortcut();
     registerVoiceShortcut();
     console.log('[voice] hotkey set to', combo.accel);
diff --git a/electron/voiceHotkeyProbe.test.js b/electron/voiceHotkeyProbe.test.js
new file mode 100644
index 00000000..7f875ce3
--- /dev/null
+++ b/electron/voiceHotkeyProbe.test.js
@@ -0,0 +1,40 @@
+// The fn dead-key deadlock (Haik, exp.16, ~99% of devices): the dictation-used marker was only
+// written by a successful transcription, the fn watcher only started once the marker existed, and
+// fn was the default hotkey, so a never-dictated install could never dictate. The fix is a boot
+// probe that arms fn WITHOUT ever prompting (IOHIDCheckAccess preflight) plus intent arming.
+const test = require('node:test');
+const assert = require('node:assert');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const swiftSrc = fs.readFileSync(path.join(__dirname, 'native', 'fn-watcher.swift'), 'utf8');
+const hotkeySrc = fs.readFileSync(path.join(__dirname, 'voiceHotkey.js'), 'utf8');
+
+test('the swift preflight refuses to prompt in --no-prompt mode', () => {
+  const preflight = swiftSrc.indexOf('--no-prompt');
+  const firstTap = swiftSrc.indexOf('func armTap');
+  assert.ok(preflight > -1, 'preflight missing');
+  assert.ok(preflight < firstTap, 'preflight must run before any tap can raise the TCC prompt');
+  assert.match(swiftSrc, /IOHIDCheckAccess\(kIOHIDRequestTypeListenEvent\)/);
+});
+
+test('boot probes fn silently when the marker is absent', () => {
+  const bootBlock = hotkeySrc.split("fs.existsSync(path.join(app.getPath('userData'), 'dictation-used'))")[1].slice(0, 400);
+  assert.match(bootBlock, /combo\.special === 'fn'.*startFnWatcher\(true\)/s,
+    'a fresh install with the default fn hotkey must get the no-prompt probe at boot');
+});
+
+test('rebinding to fn before tiers are armed also probes', () => {
+  assert.match(hotkeySrc, /else if \(combo\.special === 'fn'\) startFnWatcher\(true\);\n    unregisterFallbackShortcut/);
+});
+
+test('a focused bare Fn keydown arms the tiers and toggles', () => {
+  const relay = hotkeySrc.split('installVoiceHoldRelay')[1].slice(0, 900);
+  assert.match(relay, /input\.key === 'Fn'/);
+  assert.match(relay, /armNativeTiers\(\)/);
+  assert.match(relay, /sendFallbackToggle\(\)/);
+});
+
+test('the probe flag reaches the spawn argv', () => {
+  assert.match(hotkeySrc, /spawn\(bin, noPrompt \? \['--no-prompt'\] : \[\]/);
+});