diff --git a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/ChatRepository.kt b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/ChatRepository.kt
index 45d795b7..57bed268 100644
--- a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/ChatRepository.kt
+++ b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/ChatRepository.kt
@@ -543,7 +543,7 @@ class ChatRepository(private val reportFailure: (String) -> Unit = { LogManager.
 
     /* ── DM (личные сообщения) ── */
 
-    /** ID принятого запроса, привязанный к instance; null означает отказ очереди, событие ещё не подтверждает commit. */
+    /** ID принятого запроса, привязанный к instance; null — отказ. Возврат ещё не подтверждает commit: нужен DM_CONV_UPDATED. */
     fun dmStart(nodeId: Long, sourceChId: String, peerName: String): String? =
         NativeLib.dmStart(nodeId, sourceChId, peerName)
 
diff --git a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/NativeLib.kt b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/NativeLib.kt
index f070716a..4352f05c 100644
--- a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/NativeLib.kt
+++ b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/NativeLib.kt
@@ -10,6 +10,10 @@ interface ChatEventCallback {
     fun onEvent(type: Int, data: ByteArray?)
 }
 
+/** JNI API. start/stop/restart/resetDatabase сериализованы lifecycle mutex и вызываются из coroutine.
+ * Stop сначала ждёт frontend audio/video owners, затем join worker на IO; isReady отражает native ready.
+ * Очередь JNI подтверждает приём команды, результат операции приходит отдельным CHAT_EVT_*.
+ * JSON snapshots читаются в worker синхронно: тяжёлые getters вызывать на IO. */
 object NativeLib {
     @Volatile private var coreStopping = false
     @Volatile private var eventCallback: ChatEventCallback? = null
@@ -289,9 +293,14 @@ object NativeLib {
 
     /* Live media используют отдельную ограниченную очередь, минуя чатовый event bus. */
     fun streamOpen(id: Long, group: Long, source: Long = 0, width: Int = 0, height: Int = 0,
-                   rotation: Int = 0, audio: Boolean = true, epoch: Long = 0, videoCodec: Int = 1): Boolean =
-        nativeStreamOpen(id, group, source, width, height, rotation, audio, epoch, videoCodec)
-    fun streamWatch(group: Long): Boolean = nativeStreamWatch(group)
+                   rotation: Int = 0, audio: Boolean = true, epoch: Long = 0, videoCodec: Int = 1): Boolean {
+        if (coreStopping) { LogManager.addLog("WARN", "stream", "Open rejected during core teardown id=$id group=$group"); return false }
+        return nativeStreamOpen(id, group, source, width, height, rotation, audio, epoch, videoCodec)
+    }
+    fun streamWatch(group: Long): Boolean {
+        if (coreStopping) { LogManager.addLog("WARN", "stream", "Watch rejected during core teardown group=$group"); return false }
+        return nativeStreamWatch(group)
+    }
     fun streamFeed(id: Long, video: Boolean, pts: Long, key: Boolean, data: ByteArray, revision: Long = 0,
                    width: Int = 0, height: Int = 0, rotation: Int = 0, audio: Boolean = true, videoCodec: Int = 1): Int =
         nativeStreamFeed(id, video, pts, key, data, revision, width, height, rotation, audio, videoCodec)
@@ -308,7 +317,10 @@ object NativeLib {
     external fun streamSignalNotify(handle: Long)
     external fun streamSignalWait(handle: Long, timeoutMs: Int): Int
     external fun streamSignalClose(handle: Long)
-    fun streamPlaybackCreate(id: Long, pts: Long, audio: Boolean): Long = nativeStreamPlaybackCreate(id, pts, audio)
+    fun streamPlaybackCreate(id: Long, pts: Long, audio: Boolean): Long {
+        if (coreStopping) { LogManager.addLog("WARN", "stream", "Playback rejected during core teardown id=$id"); return 0 }
+        return nativeStreamPlaybackCreate(id, pts, audio)
+    }
     fun streamPlaybackFeed(handle: Long, pts: Long, packet: ByteArray): Int = nativeStreamPlaybackFeed(handle, pts, packet)
     fun streamPlaybackPrepare(handle: Long): Int = nativeStreamPlaybackPrepare(handle)
     fun streamPlaybackBuffered(handle: Long): Int = nativeStreamPlaybackBuffered(handle)
@@ -390,7 +402,10 @@ object NativeLib {
     private external fun nativeRadioCall(id: Long, group: Long, peer: Long, action: Int): Boolean
 
     /* ── P2P аудио-звонок (медиа) ── */
-    fun callAudioStart(callId: Long): Boolean = !coreStopping && nativeCallAudioStart(callId)
+    fun callAudioStart(callId: Long): Boolean {
+        if (coreStopping) { LogManager.addLog("WARN", "Call", "Audio start rejected during core teardown id=$callId"); return false }
+        return nativeCallAudioStart(callId)
+    }
     /** Настоящий raw PCM и mute кадра: зануление выполняется в core после AEC/AGC. */
     fun callAudioFeed(callId: Long, samples: ShortArray, muted: Boolean, capturePtsUs: Long): Boolean =
         nativeCallAudioFeed(callId, samples, muted, capturePtsUs)
@@ -410,11 +425,17 @@ object NativeLib {
     /* ── Рация (PTT walkie-talkie) ── */
     fun radioSetActive(groupId: Long, on: Boolean) { nativeRadioSetActive(groupId, on) }
     fun radioSubscribers(groupId: Long): Int = nativeRadioSubscribers(groupId)
-    fun radioAudioStart(groupId: Long, channels: Int): Boolean = !coreStopping && nativeRadioAudioStart(groupId, channels)
+    fun radioAudioStart(groupId: Long, channels: Int): Boolean {
+        if (coreStopping) { LogManager.addLog("WARN", "Radio", "Audio start rejected during core teardown group=$groupId"); return false }
+        return nativeRadioAudioStart(groupId, channels)
+    }
     fun radioAudioFeed(groupId: Long, samples: ShortArray): Boolean = nativeRadioAudioFeed(groupId, samples)
     fun radioAudioPull(groupId: Long, out: ShortArray, playedFrames: Long): Int = nativeRadioAudioPull(groupId, out, playedFrames)
     fun radioAudioStop() { nativeRadioAudioStop() }
-    fun radioCaptureStart(groupId: Long, channels: Int, mode: Int): Boolean = !coreStopping && nativeRadioCaptureStart(groupId, channels, mode)
+    fun radioCaptureStart(groupId: Long, channels: Int, mode: Int): Boolean {
+        if (coreStopping) { LogManager.addLog("WARN", "Radio", "Capture rejected during core teardown group=$groupId mode=$mode"); return false }
+        return nativeRadioCaptureStart(groupId, channels, mode)
+    }
     /** true — копия снимка поставлена живому worker; проверка и применение ещё не подтверждены.
      * ConfigProvider.onRadioSettingsApplied вернёт тот же requestId и результат атомарной проверки/применения.
      * false — запрос отклонён (включая отсутствие callback). Stop/restart может отменить ожидающий снимок без ACK;