diff --git a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamTxStats.kt b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamTxStats.kt
index ae81e338..bdfdb497 100644
--- a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamTxStats.kt
+++ b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamTxStats.kt
@@ -7,14 +7,17 @@ data class StreamBufferPositions(val first: Long = 0, val head: Long = 0, val to
         else ((next.coerceIn(first, head) - first).toDouble() / (head - first)).toFloat()
 }
 
-/** Все поля в байтах; ACK — десять завершённых интервалов по 100ms, для всех соединений ядра. */
+/** TX snapshot: sampleUs — MONOTONIC мкс, счётчики данных — байты, connections — число соединений.
+ * acked1s — десять завершённых интервалов по 100 мс для всех соединений ядра.
+ * buffer.first/head и peer worst/best — seq пачек, total — все получатели, peers — до 16 отставших.
+ * fromNative читает 13 + 4*peerCount полей JNI; peer ID сохраняет uint64, ошибки формата бросаются caller. */
 data class StreamTxStats(val id: Long, val sampleUs: Long, val videoBytes: Long, val audioBytes: Long,
                          val streamBytes: Long, val transportBytes: Long, val inflightBytes: Long,
                          val acked1s: Long, val totalBytes: Long, val connections: Long, val buffer: StreamBufferPositions) {
     companion object {
         fun fromNative(id: Long, data: LongArray): StreamTxStats {
             require(data.size >= 13 && data.take(13).all { it >= 0 } && data[12] <= 16)
-            require(data.size == 13 + data[12].toInt() * 4 && data[9] <= data[10] && data[12] <= data[11])
+            require(data.size == 13 + data[12].toInt() * 4 && data[9] <= data[10] && data[12] <= data[11] && data[11] <= Int.MAX_VALUE)
             val peers = List(data[12].toInt()) { i ->
                 val offset = 13 + i * 4
                 require(data[offset + 1] >= 0 && data[offset + 2] >= data[offset + 1] && data[offset + 3] in 1..255)
diff --git a/tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamMetadataTest.kt b/tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamMetadataTest.kt
new file mode 100644
index 00000000..90ae5dc6
--- /dev/null
+++ b/tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamMetadataTest.kt
@@ -0,0 +1,46 @@
+package com.utun.chat.data
+
+import org.junit.Assert.*
+import org.junit.Test
+
+class StreamMetadataTest {
+    @Test fun sourceIdsAndEpochsPreserveUnsigned64BitsAndEmptyNamesUseTheId() {
+        val source = StreamSource.parse("""[{"id":"18446744073709551615","epoch":"ffffffffffffffff","name":"","self":1}]""").single()
+        assertEquals(-1L, source.id); assertEquals(-1L, source.epoch)
+        assertEquals("18446744073709551615", source.displayName); assertTrue(source.self)
+    }
+
+    @Test fun sourceSnapshotsRejectZeroAndDuplicateIdentities() {
+        for (json in listOf("""[{"id":"0","epoch":"1","name":"a","self":0}]""",
+            """[{"id":"1","epoch":"0","name":"a","self":0}]""",
+            """[{"id":"1","epoch":"a","name":"a","self":0},{"id":"1","epoch":"b","name":"b","self":1}]""")) {
+            assertThrows(IllegalArgumentException::class.java) { StreamSource.parse(json) }
+        }
+    }
+
+    @Test fun transmitSnapshotMapsUnitsAndKeepsUnsignedPeerId() {
+        val data = longArrayOf(100, 1, 2, 3, 4, 5, 6, 7, 8, 10, 20, 2, 1, -1, 12, 18, 3)
+        val stats = StreamTxStats.fromNative(42, data)
+        assertEquals(100L, stats.sampleUs); assertEquals(8L, stats.connections); assertEquals(6L, stats.acked1s)
+        assertEquals(2, stats.buffer.total); assertEquals(StreamBufferPeer(-1, 12, 18, 3), stats.buffer.peers.single())
+        assertEquals(0f, stats.buffer.fraction(0), 0f); assertEquals(0.5f, stats.buffer.fraction(15), 0f)
+        assertEquals(1f, stats.buffer.fraction(30), 0f); assertEquals(1f, StreamBufferPositions().fraction(0), 0f)
+    }
+
+    @Test fun malformedStatsCannotOverflowCountsOrReverseTheBufferWindow() {
+        val valid = longArrayOf(100, 1, 2, 3, 4, 5, 6, 7, 8, 10, 20, 2, 1, -1, 12, 18, 3)
+        for (data in listOf(valid.copyOf(12), valid + 0, valid.copyOf().also { it[11] = Int.MAX_VALUE.toLong() + 1 },
+            valid.copyOf().also { it[9] = 21 }, valid.copyOf().also { it[12] = 17 },
+            valid.copyOf().also { it[15] = 11 }, valid.copyOf().also { it[16] = 256 })) {
+            assertThrows(IllegalArgumentException::class.java) { StreamTxStats.fromNative(42, data) }
+        }
+    }
+
+    @Test fun nativeTelemetryKeepsKnownUnknownAndLocalReserveSeparate() {
+        val data = """{"self":"local","nodes":[{"name":"relay","flags":7,"us":2000000,"frames":4},{"name":"source","flags":0,"us":0,"frames":0}]}"""
+        val stats = StreamPlaybackTelemetry.fromNative(data.toByteArray(), 500000, 1100)
+        assertEquals(3, stats.nodes.size); assertEquals(2_000_000L, stats.nodes[0].durationUs)
+        assertTrue(stats.nodes[0].stale); assertTrue(stats.nodes[0].down); assertNull(stats.nodes[1].durationUs)
+        assertEquals(500_000L, stats.nodes[2].durationUs); assertEquals("1.1x", stats.speed)
+    }
+}