From 2ace3270324750f0d70cba77855f40057d8afd92 Mon Sep 17 00:00:00 2001
From: 2sumtech <2sumtech@gmail.com>
Date: Mon, 21 Sep 2026 10:45:44 -0700
Subject: [PATCH] fix(speech): fail when the audio stream ends without a
 terminator

`mmx speech synthesize --stream` ended its SSE loop on the first `done`
read from the response body, whether or not the server had sent a
`data.status: 2` chunk or `data: [DONE]`. A connection dropped
mid-synthesis therefore piped the partial audio to stdout and exited 0,
so `mmx speech synthesize --stream > out.mp3` produced a silently
truncated file that the caller could not distinguish from a complete one.

`decodeAudioStream` already rejects a stream that completes with no audio
at all (`API stream ended without audio data.`); a stream that delivers
one chunk and then drops was the gap.

Track the terminator and raise `Stream disconnected before audio
completed.` with the network exit code (6) when the stream ends without
one, mirroring the text-chat fix, and document the scenario in ERRORS.md.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
---
 ERRORS.md                       |  1 +
 src/utils/audio-stream.ts       | 20 ++++++++++++++++++--
 test/utils/audio-stream.test.ts | 14 ++++++++++++++
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/ERRORS.md b/ERRORS.md
index 88f8a4af..7e6d3b9e 100644
--- a/ERRORS.md
+++ b/ERRORS.md
@@ -118,6 +118,7 @@ This document lists all error scenarios and the messages users will see.
 | `--text-file` unreadable | `Cannot read file: ${e.message}` |
 | `--out` path no write permission | `Permission denied: cannot write to "${outPath}".` |
 | Disk full | `Disk full — cannot write audio file.` |
+| `--stream` connection drops before the final audio chunk | `Stream disconnected before audio completed.` |
 
 ### `mmx speech transcribe`
 
diff --git a/src/utils/audio-stream.ts b/src/utils/audio-stream.ts
index a6bc2d7d..032ff270 100644
--- a/src/utils/audio-stream.ts
+++ b/src/utils/audio-stream.ts
@@ -37,6 +37,13 @@ function missingAudioError(): CLIError {
   );
 }
 
+function truncatedStreamError(): CLIError {
+  return new CLIError(
+    'Stream disconnected before audio completed.',
+    ExitCode.NETWORK,
+  );
+}
+
 export async function* decodeAudioStream(
   response: Response,
 ): AsyncGenerator<Uint8Array<ArrayBuffer>> {
@@ -61,8 +68,13 @@ export async function* decodeAudioStream(
   }
 
   let receivedAudio = false;
+  let streamCompleted = false;
   for await (const event of parseSSE(response)) {
-    if (!event.data || event.data === '[DONE]') break;
+    if (!event.data) break;
+    if (event.data === '[DONE]') {
+      streamCompleted = true;
+      break;
+    }
 
     let parsed: AudioPayload;
     try {
@@ -82,10 +94,14 @@ export async function* decodeAudioStream(
       yield decodeHexAudio(hex);
     }
 
-    if (parsed.data?.status === 2) break;
+    if (parsed.data?.status === 2) {
+      streamCompleted = true;
+      break;
+    }
   }
 
   if (!receivedAudio) throw missingAudioError();
+  if (!streamCompleted) throw truncatedStreamError();
 }
 
 export async function pipeAudioStream(response: Response): Promise<void> {
diff --git a/test/utils/audio-stream.test.ts b/test/utils/audio-stream.test.ts
index 23bdefd4..03731c2d 100644
--- a/test/utils/audio-stream.test.ts
+++ b/test/utils/audio-stream.test.ts
@@ -53,4 +53,18 @@ describe('decodeAudioStream', () => {
       'API stream ended without audio data',
     );
   });
+
+  it('rejects a stream that closes after audio chunks but without a terminator', async () => {
+    // A dropped connection: chunks arrive, then the body ends with no
+    // `status: 2` chunk and no `data: [DONE]` terminator.
+    const response = new Response(
+      'data: {"data":{"audio":"414243","status":1}}\n\n'
+      + 'data: {"data":{"audio":"444546","status":1}}\n\n',
+      { headers: { 'Content-Type': 'text/event-stream' } },
+    );
+
+    await expect(collectAudio(response)).rejects.toThrow(
+      'Stream disconnected before audio completed.',
+    );
+  });
 });