fix(meet-audio): zero-PCM keepalive so Meet keeps the bot joined (#2945)

app/src-tauri/src/meet_audio/audio_bridge.js

@@ -75,6 +75,37 @@
         " state=" +
         ctx.state
     );
+    // Keepalive: a permanently-running source of zero samples connected
+    // to `dest`. Without this, Meet sees an audio track that is `live`
+    // but produces zero PCM during silence — some Meet builds drop the
+    // bot for "no audio activity" after a few seconds. Mirrors the
+    // camera-bridge 1px-bob keepalive in `meet_video/camera_bridge.js`
+    // (see comment "keeps the WebRTC encoder from dropping the stream
+    // as 'frozen'"). Brain PCM mixes in via `__openhumanFeedPcm` over
+    // the top — zero + real = real, so this does NOT mute the bot.
+    //
+    // NOT pushed into `activeSources`: barge-in (`__openhumanFlushAudio`)
+    // must not stop the keepalive.
+    try {
+      var silenceSamples = Math.max(1, Math.floor(ctx.sampleRate / 10)); // 100 ms
+      var silenceBuffer = ctx.createBuffer(1, silenceSamples, ctx.sampleRate);
+      // createBuffer initializes to zeros — no explicit fill needed.
+      var silenceSource = ctx.createBufferSource();
+      silenceSource.buffer = silenceBuffer;
+      silenceSource.loop = true;
+      silenceSource.connect(dest);
+      silenceSource.start(0);
+      console.log(
+        "[openhuman-audio-bridge] keepalive silence source started buffer_samples=" +
+          silenceSamples
+      );
+    } catch (e) {
+      // Keepalive failure is non-fatal — the bridge still functions for
+      // active speech. Log so support can spot it in user reports.
+      console.warn(
+        "[openhuman-audio-bridge] keepalive setup failed err=" + e
+      );
+    }
     return ctx;
   }
 

app/src-tauri/src/meet_audio/inject.rs

@@ -302,3 +302,32 @@ pub async fn flush_audio_bridge(cdp: &mut CdpConn, session: &str) -> Result<i64,
         .unwrap_or(0);
     Ok(stopped)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::AUDIO_BRIDGE_JS;
+
+    /// The page-side audio bridge must contain a permanent zero-PCM
+    /// keepalive source connected to the WebRTC destination. Without
+    /// it, Meet drops the bot for "no audio activity" during silence
+    /// (see `docs/superpowers/specs/2026-06-04-meet-audio-keepalive-design.md`).
+    ///
+    /// This is a presence test — it does not exercise the WebAudio
+    /// runtime, only asserts the keepalive code shipped intact in the
+    /// included JS. If a future refactor moves the keepalive to a
+    /// different file or reshapes the log line, update the assertions
+    /// here together with the change.
+    #[test]
+    fn audio_bridge_contains_keepalive_block() {
+        assert!(
+            AUDIO_BRIDGE_JS.contains("keepalive silence source started"),
+            "audio_bridge.js is missing the keepalive console.log marker; \
+             the silence source may have been removed (see #2945)"
+        );
+        assert!(
+            AUDIO_BRIDGE_JS.contains("silenceSource.start(0)"),
+            "audio_bridge.js is missing `silenceSource.start(0)`; \
+             the keepalive setup may have been removed (see #2945)"
+        );
+    }
+}