fix(iOS): persist PCM fallback only on explicit API format rejection

apps/ios/Sources/Voice/TalkModeManager.swift

@@ -7,6 +7,23 @@ import Observation
 import OSLog
 import Speech
 
+private final class StreamFailureBox: @unchecked Sendable {
+    private let lock = NSLock()
+    private var valueInternal: Error?
+
+    func set(_ error: Error) {
+        self.lock.lock()
+        self.valueInternal = error
+        self.lock.unlock()
+    }
+
+    var value: Error? {
+        self.lock.lock()
+        defer { self.lock.unlock() }
+        return self.valueInternal
+    }
+}
+
 // This file intentionally centralizes talk mode state + behavior.
 // It's large, and splitting would force `private` -> `fileprivate` across many members.
 // We'll refactor into smaller files when the surface stabilizes.
@@ -1040,7 +1057,7 @@ final class TalkModeManager: NSObject {
                 let request = makeRequest(outputFormat: outputFormat)
 
                 let client = ElevenLabsTTSClient(apiKey: apiKey)
-                let stream = client.streamSynthesize(voiceId: voiceId, request: request)
+                let rawStream = client.streamSynthesize(voiceId: voiceId, request: request)
 
                 if self.interruptOnSpeech {
                     do {
@@ -1055,12 +1072,16 @@ final class TalkModeManager: NSObject {
                 let sampleRate = TalkTTSValidation.pcmSampleRate(from: outputFormat)
                 let result: StreamingPlaybackResult
                 if let sampleRate {
+                    let streamFailure = StreamFailureBox()
+                    let stream = Self.monitorStreamFailures(rawStream, failureBox: streamFailure)
                     self.lastPlaybackWasPCM = true
                     var playback = await self.pcmPlayer.play(stream: stream, sampleRate: sampleRate)
                     if !playback.finished, playback.interruptedAt == nil {
                         let mp3Format = ElevenLabsTTSClient.validatedOutputFormat("mp3_44100_128")
                         self.logger.warning("pcm playback failed; retrying mp3")
-                        self.pcmFormatUnavailable = true
+                        if Self.isPCMFormatRejectedByAPI(streamFailure.value) {
+                            self.pcmFormatUnavailable = true
+                        }
                         self.lastPlaybackWasPCM = false
                         let mp3Stream = client.streamSynthesize(
                             voiceId: voiceId,
@@ -1070,7 +1091,7 @@ final class TalkModeManager: NSObject {
                     result = playback
                 } else {
                     self.lastPlaybackWasPCM = false
-                    result = await self.mp3Player.play(stream: stream)
+                    result = await self.mp3Player.play(stream: rawStream)
                 }
                 let duration = Date().timeIntervalSince(started)
                 self.logger.info("elevenlabs stream finished=\(result.finished, privacy: .public) dur=\(duration, privacy: .public)s")
@@ -1545,6 +1566,39 @@ final class TalkModeManager: NSObject {
         self.pcmFormatUnavailable ? "mp3_44100_128" : "pcm_44100"
     }
 
+    private static func monitorStreamFailures(
+        _ stream: AsyncThrowingStream<Data, Error>,
+        failureBox: StreamFailureBox
+    ) -> AsyncThrowingStream<Data, Error>
+    {
+        AsyncThrowingStream { continuation in
+            let task = Task {
+                do {
+                    for try await chunk in stream {
+                        continuation.yield(chunk)
+                    }
+                    continuation.finish()
+                } catch {
+                    failureBox.set(error)
+                    continuation.finish(throwing: error)
+                }
+            }
+            continuation.onTermination = { _ in
+                task.cancel()
+            }
+        }
+    }
+
+    private static func isPCMFormatRejectedByAPI(_ error: Error?) -> Bool {
+        guard let error = error as NSError? else { return false }
+        guard error.domain == "ElevenLabsTTS", error.code >= 400 else { return false }
+        let message = (error.userInfo[NSLocalizedDescriptionKey] as? String ?? error.localizedDescription).lowercased()
+        return message.contains("output_format")
+            || message.contains("pcm_")
+            || message.contains("pcm ")
+            || message.contains("subscription_required")
+    }
+
     private static func makeBufferedAudioStream(chunks: [Data]) -> AsyncThrowingStream<Data, Error> {
         AsyncThrowingStream { continuation in
             for chunk in chunks {
@@ -1586,21 +1640,25 @@ final class TalkModeManager: NSObject {
             text: text,
             context: context,
             outputFormat: context.outputFormat)
-        let stream: AsyncThrowingStream<Data, Error>
+        let rawStream: AsyncThrowingStream<Data, Error>
         if let prefetchedAudio, !prefetchedAudio.chunks.isEmpty {
-            stream = Self.makeBufferedAudioStream(chunks: prefetchedAudio.chunks)
+            rawStream = Self.makeBufferedAudioStream(chunks: prefetchedAudio.chunks)
         } else {
-            stream = client.streamSynthesize(voiceId: voiceId, request: request)
+            rawStream = client.streamSynthesize(voiceId: voiceId, request: request)
         }
         let playbackFormat = prefetchedAudio?.outputFormat ?? context.outputFormat
         let sampleRate = TalkTTSValidation.pcmSampleRate(from: playbackFormat)
         let result: StreamingPlaybackResult
         if let sampleRate {
+            let streamFailure = StreamFailureBox()
+            let stream = Self.monitorStreamFailures(rawStream, failureBox: streamFailure)
             self.lastPlaybackWasPCM = true
             var playback = await self.pcmPlayer.play(stream: stream, sampleRate: sampleRate)
             if !playback.finished, playback.interruptedAt == nil {
                 self.logger.warning("pcm playback failed; retrying mp3")
-                self.pcmFormatUnavailable = true
+                if Self.isPCMFormatRejectedByAPI(streamFailure.value) {
+                    self.pcmFormatUnavailable = true
+                }
                 self.lastPlaybackWasPCM = false
                 let mp3Format = ElevenLabsTTSClient.validatedOutputFormat("mp3_44100_128")
                 let mp3Stream = client.streamSynthesize(
@@ -1614,7 +1672,7 @@ final class TalkModeManager: NSObject {
             result = playback
         } else {
             self.lastPlaybackWasPCM = false
-            result = await self.mp3Player.play(stream: stream)
+            result = await self.mp3Player.play(stream: rawStream)
         }
         if !result.finished, let interruptedAt = result.interruptedAt {
             self.lastInterruptedAtSeconds = interruptedAt
@@ -2118,6 +2176,10 @@ private final class AudioTapDiagnostics: @unchecked Sendable {
 
 #if DEBUG
 extension TalkModeManager {
+    static func _test_isPCMFormatRejectedByAPI(_ error: Error?) -> Bool {
+        self.isPCMFormatRejectedByAPI(error)
+    }
+
     func _test_seedTranscript(_ transcript: String) {
         self.lastTranscript = transcript
         self.lastHeard = Date()

apps/ios/Tests/TalkModeConfigParsingTests.swift

@@ -1,3 +1,4 @@
+import Foundation
 import Testing
 @testable import OpenClaw
 
@@ -28,4 +29,22 @@ import Testing
         let selection = TalkModeManager.selectTalkProviderConfig(talk)
         #expect(selection == nil)
     }
+
+    @Test func detectsPCMFormatRejectionFromElevenLabsError() {
+        let error = NSError(
+            domain: "ElevenLabsTTS",
+            code: 403,
+            userInfo: [
+                NSLocalizedDescriptionKey: "ElevenLabs failed: 403 subscription_required output_format=pcm_44100",
+            ])
+        #expect(TalkModeManager._test_isPCMFormatRejectedByAPI(error))
+    }
+
+    @Test func ignoresGenericPlaybackFailuresForPCMFormatRejection() {
+        let error = NSError(
+            domain: "StreamingAudio",
+            code: -1,
+            userInfo: [NSLocalizedDescriptionKey: "queue enqueue failed"])
+        #expect(TalkModeManager._test_isPCMFormatRejectedByAPI(error) == false)
+    }
 }