fix(server): report an audio-only server healthy once its worker is ready

src/server/routes/availability_tests.rs

@@ -159,6 +159,25 @@ async fn post(app: axum::Router, path: &str, body: Value) -> (StatusCode, Value)
     (status, body)
 }
 
+async fn get(app: axum::Router, path: &str) -> (StatusCode, Value) {
+    let response = app
+        .oneshot(
+            Request::builder()
+                .method(Method::GET)
+                .uri(path)
+                .body(Body::empty())
+                .expect("request builds"),
+        )
+        .await
+        .expect("route responds");
+    let status = response.status();
+    let bytes = axum::body::to_bytes(response.into_body(), usize::MAX)
+        .await
+        .expect("body reads");
+    let body = serde_json::from_slice(&bytes).expect("health body is JSON");
+    (status, body)
+}
+
 #[tokio::test]
 async fn embedding_only_server_returns_501_on_all_generation_routes() {
     let cases = [
@@ -231,6 +250,16 @@ async fn audio_only_server_names_the_served_routes() {
     assert!(message.contains("/v1/audio/translations"), "{body}");
 }
 
+#[tokio::test]
+async fn audio_only_server_reports_healthy_after_its_worker_is_ready() {
+    let state = state_with(ModelProvider::chat_unavailable_for_route_tests())
+        .with_audio_model(Some(Arc::new(SideAudioProvider)));
+    let (status, body) = get(create_app(state), "/health").await;
+
+    assert_eq!(status, StatusCode::OK, "{body}");
+    assert_eq!(body, json!({ "status": "ok" }));
+}
+
 #[tokio::test]
 async fn exited_chat_worker_returns_503_without_channel_details() {
     let state = state_with(ModelProvider::exited_chat_worker_for_route_tests());

src/server/routes/health.rs

@@ -60,13 +60,22 @@ fn side_model_ready(state: &AppState) -> bool {
 ///
 /// `200 {"status": "ok"}` once the serving worker is up; the b10621 loading
 /// envelope before that. Never reports saturation (see module docs).
+///
+/// Used by: `mlxcel-server` and `mlxcel serve`.
 pub async fn health_check(State(state): State<AppState>) -> Response {
     // A server started with b10621's `--embeddings` or `--reranking` has no
     // chat worker to be "loaded", and reporting it unhealthy forever would
     // make the mode unusable behind any container probe (#1452). Readiness
     // there is whether the worker the mode selected came up.
     let ready = if state.config.embedding_serving_mode.blocks_generation() {
         side_model_ready(&state)
+    } else if state.model_provider.is_chat_unavailable() && state.audio_model.is_some() {
+        // Whisper and Kokoro checkpoints are primary audio-only models: their
+        // dedicated worker has already loaded before the provider is installed,
+        // while the deliberately unused chat worker records a terminal state.
+        // Treat that combination as ready so the documented `-m <checkpoint>`
+        // audio server can pass container health checks.
+        true
     } else {
         state.model_provider.is_loaded()
     };