fix: avoid iOS talk mode audio tap crash

AGENTS.md

@@ -23,6 +23,7 @@
 - Naming: match source names with `*.test.ts`; e2e in `*.e2e.test.ts`.
 - Run `pnpm test` (or `pnpm test:coverage`) before pushing when you touch logic.
 - Pure test additions/fixes generally do **not** need a changelog entry unless they alter user-facing behavior or the user asks for one.
+- Mobile: before using a simulator, check for connected real devices (iOS + Android) and prefer them when available.
 
 ## Commit & Pull Request Guidelines
 - Create commits with `scripts/committer "<msg>" <file...>`; avoid manual `git add`/`git commit` so staging stays scoped.

CHANGELOG.md

@@ -20,6 +20,7 @@
 - macOS menu: device list now uses `node.list` (devices only; no agent/tool presence entries).
 - macOS menu: device list now shows connected nodes only.
 - iOS node: fix ReplayKit screen recording crash caused by queue isolation assertions during capture.
+- iOS Talk Mode: avoid audio tap queue assertions when starting recognition.
 - iOS/Android nodes: bridge auto-connect refreshes stale tokens and settings now show richer bridge/device details.
 - iOS/Android nodes: status pill now surfaces camera activity instead of overlay toasts.
 - iOS/Android/macOS nodes: camera snaps recompress to keep base64 payloads under 5 MB.

apps/ios/Sources/RootCanvas.swift

@@ -253,7 +253,7 @@ private struct CanvasContent: View {
 private struct OverlayButton: View {
     let systemImage: String
     let brighten: Bool
-    var tint: Color? = nil
+    var tint: Color?
     var isActive: Bool = false
     let action: () -> Void
 

apps/ios/Sources/Voice/TalkModeManager.swift

@@ -7,6 +7,7 @@ import Speech
 @MainActor
 @Observable
 final class TalkModeManager: NSObject {
+    private typealias SpeechRequest = SFSpeechAudioBufferRecognitionRequest
     var isEnabled: Bool = false
     var isListening: Bool = false
     var isSpeaking: Bool = false
@@ -105,9 +106,8 @@ final class TalkModeManager: NSObject {
         let input = self.audioEngine.inputNode
         let format = input.outputFormat(forBus: 0)
         input.removeTap(onBus: 0)
-        input.installTap(onBus: 0, bufferSize: 2048, format: format) { [weak request] buffer, _ in
+        let tapBlock = Self.makeAudioTapAppendCallback(request: request)
-            request?.append(buffer)
+        input.installTap(onBus: 0, bufferSize: 2048, format: format, block: tapBlock)
-        }
 
         self.audioEngine.prepare()
         try self.audioEngine.start()
@@ -135,6 +135,12 @@ final class TalkModeManager: NSObject {
         self.speechRecognizer = nil
     }
 
+    private nonisolated static func makeAudioTapAppendCallback(request: SpeechRequest) -> AVAudioNodeTapBlock {
+        { buffer, _ in
+            request.append(buffer)
+        }
+    }
+
     private func handleTranscript(transcript: String, isFinal: Bool) async {
         let trimmed = transcript.trimmingCharacters(in: .whitespacesAndNewlines)
         if self.isSpeaking, self.interruptOnSpeech {