diff --git a/backend/cpp/audio-cpp/family_gate.cpp b/backend/cpp/audio-cpp/family_gate.cpp
index 83ccd42fa..2515c7abb 100644
--- a/backend/cpp/audio-cpp/family_gate.cpp
+++ b/backend/cpp/audio-cpp/family_gate.cpp
@@ -73,9 +73,12 @@ namespace {
 // supertonic: upstream's docs/gguf.md:90 records its 16-bit GGUF column as
 // "---", i.e. NOT TESTED, and its q8_0 as "No (unsupported weight dtype)". Only
 // the `orig` package is marked Pass, and its 698 weight tensors are f32 while
-// its 72 index and shape constants are i64. Attributed rather than assumed: the
-// abort is identical through the unary TTS RPC and through TTSStream, so it is
-// the packaging and not the streaming path.
+// its 72 index and shape constants are i64. The f16 abort is a LOCAL
+// OBSERVATION rather than an upstream claim, and it is attributed rather than
+// assumed: it is identical through the unary TTS RPC and through TTSStream, so
+// it is the packaging and not the streaming path. q8_0 was never run here and is
+// refused on upstream's "unsupported weight dtype" alone, which is the weaker of
+// the two claims. See the header for why keeping them apart matters.
 //
 // TO REMOVE AN ENTRY: bump AUDIO_CPP_VERSION past a fix, load a package in the
 // refused dtype, and synthesise. If audio comes out, delete the entry. No test
diff --git a/backend/cpp/audio-cpp/family_gate.h b/backend/cpp/audio-cpp/family_gate.h
index 7e8210fd2..e516ca54b 100644
--- a/backend/cpp/audio-cpp/family_gate.h
+++ b/backend/cpp/audio-cpp/family_gate.h
@@ -36,12 +36,27 @@ FamilyDecision decide_family(bool path_is_gguf, const std::string &embedded_fami
 // string a TensorMetadata carries ("f32", "f16", "q8_0", "i64", ...).
 //
 // This is a LIST OF FAMILIES THAT CRASH THE PROCESS, not a list of families that
-// perform badly. It exists because the failure is not an exception: loading a
-// supertonic package whose weights are f16 or q8_0 reaches ggml_concat with one
-// f16 operand and one f32 one, and ggml_abort takes the backend down with
-// SIGABRT on the FIRST request. Nothing upstream of the load can catch that, so
-// an operator sees a model that loaded successfully and a backend that dies on
-// every request with no status and no message.
+// perform badly. It exists because the failure is not an exception: loading the
+// supertonic f16 GGUF package reaches ggml_concat with one f16 operand and one
+// f32 one, GGML_ASSERT(a->type == b->type) fails (external/ggml/src/ggml.c:2595)
+// and ggml_abort takes the backend down with SIGABRT on the FIRST request.
+// Nothing upstream of the load can catch that, so an operator sees a model that
+// loaded successfully and a backend that dies on every request with no status
+// and no message.
+//
+// EVIDENCE, per dtype, because the two are not equally attested:
+//   - f16 was OBSERVED to abort here, identically through the unary TTS RPC and
+//     through TTSStream, so it is the packaging and not the streaming path.
+//     Upstream's docs/gguf.md:90 has supertonic's 16-bit column as "---", which
+//     its own legend (:53) defines as not tested, so upstream neither confirms
+//     nor contradicts it.
+//   - q8_0 was NOT run here. Upstream records it as "No (unsupported weight
+//     dtype)" in the same row, which is a weaker claim than the f16 abort: it
+//     says the format is unusable, not that it takes the process down.
+// Both are refused, because the allow list is what the family CAN run (f32 for
+// weights, i64 for the shape and index constants) rather than a list of the
+// dtypes that fail, and a format upstream calls unusable has no business being
+// loaded either way.
 //
 // A family with no entry is unrestricted, which is every family but one.
 //
diff --git a/backend/cpp/audio-cpp/streaming_driver_ctest.cpp b/backend/cpp/audio-cpp/streaming_driver_ctest.cpp
index 95b49c0ef..e25616419 100644
--- a/backend/cpp/audio-cpp/streaming_driver_ctest.cpp
+++ b/backend/cpp/audio-cpp/streaming_driver_ctest.cpp
@@ -1,5 +1,6 @@
 // Tests for the streaming drivers in loaded_model: begin_stream,
-// run_streaming_pull, run_streaming_audio and run_streaming_live.
+// run_streaming_pull, run_streaming_audio and run_streaming_live, plus
+// resolve_model_path, which lives in the same engine-linked unit.
 //
 // Engine-linked, so this runs through ctest rather than
 // backend/cpp/run-unit-tests.sh. It builds no model and loads no file: a
@@ -865,7 +866,83 @@ static void test_live_refuses_a_non_streaming_session() {
           "run_streaming_live refuses a session with no streaming half");
 }
 
+// --------------------------------------------------------------------------
+// resolve_model_path
+// --------------------------------------------------------------------------
+//
+// It lives in loaded_model.cpp and is a pure (dir, file, name) -> string, so it
+// is tested here rather than in a standalone unit: that file cannot compile
+// without the engine headers.
+//
+// It is tested at all because it shipped a bug no test could have caught. THE
+// SHAPES BELOW ARE THE PRODUCTION SHAPES, not convenient ones, and that
+// distinction is the entire point. Task 15 verified the bundled: form with a
+// hand-written LoadModel that left ModelFile empty, which is the one shape the
+// server never produces: pkg/model/loader.go's LoadModelWithFile always fills
+// ModelFile with filepath.Join(ModelPath, model), and core/backend/options.go
+// only overrides it for a managed artifact. The first case below is therefore
+// the regression test; the other three are what it must not have broken.
+
+// std::string::ends_with is C++20 and this target is C++17.
+static bool ends_with(const std::string &value, const std::string &suffix) {
+    return value.size() >= suffix.size() &&
+           value.compare(value.size() - suffix.size(), suffix.size(), suffix) == 0;
+}
+
+// THE REGRESSION CASE. What a model YAML saying `model: bundled:silero_vad`
+// actually arrives as: Model intact, ModelFile joined onto the models directory.
+static void test_bundled_in_model_survives_a_joined_model_file() {
+    const std::string resolved = audiocpp_backend::resolve_model_path(
+        "/models", "/models/bundled:silero_vad", "bundled:silero_vad");
+
+    check(ends_with(resolved, "/assets/silero_vad"),
+          "bundled: in Model resolves under the package assets dir (got \"" +
+              resolved + "\")");
+    // Checked separately from the suffix because this is the failure that
+    // shipped: the joined ModelFile came back verbatim and the load died on
+    // "model path does not exist: /models/bundled:silero_vad".
+    check(resolved.find("/models/") == std::string::npos,
+          "bundled: in Model is not resolved against the models directory (got \"" +
+              resolved + "\")");
+}
+
+// Task 15's shape: the form in ModelFile with Model empty. It worked before the
+// fix and must keep working.
+static void test_bundled_in_model_file_still_resolves() {
+    const std::string resolved =
+        audiocpp_backend::resolve_model_path("", "bundled:marblenet_vad", "");
+
+    check(ends_with(resolved, "/assets/marblenet_vad"),
+          "bundled: in ModelFile still resolves under the package assets dir (got \"" +
+              resolved + "\")");
+}
+
+// The ordinary case, and the one the bundled: lookup must not capture: a real
+// artifact path in ModelFile with a plain name in Model.
+static void test_a_plain_name_resolves_to_the_model_file() {
+    const std::string resolved = audiocpp_backend::resolve_model_path(
+        "/models", "/models/chatterbox-q8_0.gguf", "chatterbox-q8_0.gguf");
+
+    check_eq(resolved, "/models/chatterbox-q8_0.gguf",
+             "a plain name resolves to the absolute ModelFile");
+}
+
+// A relative ModelFile is still joined onto ModelPath. The fix does not touch
+// this branch, which is why it is pinned: the bundled: lookup now runs before it
+// and has to fall through for every non-bundled input.
+static void test_a_relative_model_file_joins_the_model_path() {
+    const std::string resolved = audiocpp_backend::resolve_model_path(
+        "/models", "sub/nemotron-asr-q8_0.gguf", "nemotron-asr");
+
+    check_eq(resolved, "/models/sub/nemotron-asr-q8_0.gguf",
+             "a relative ModelFile joins the models directory");
+}
+
 int main() {
+    test_bundled_in_model_survives_a_joined_model_file();
+    test_bundled_in_model_file_still_resolves();
+    test_a_plain_name_resolves_to_the_model_file();
+    test_a_relative_model_file_joins_the_model_path();
     test_begin_stream_prepares_then_starts();
     test_base_start_stream_resets();
     test_begin_stream_refuses_a_non_streaming_session();
diff --git a/core/gallery/importers/importers_test.go b/core/gallery/importers/importers_test.go
index 70da1d01e..9d0ea89c3 100644
--- a/core/gallery/importers/importers_test.go
+++ b/core/gallery/importers/importers_test.go
@@ -466,6 +466,14 @@ var _ = Describe("audio-cpp importer registration", func() {
 	// GGUF repo hosts 30-odd families in one place, so repo-level matching
 	// would be a coin flip. An importer that matched .gguf would additionally
 	// capture every llama.cpp repo it saw first.
+	//
+	// THIS IS A TRIPWIRE, NOT COVERAGE. It exercises no audio-cpp behaviour and
+	// cannot go red for anything but the one act it is aimed at: someone adding
+	// an AudioCpp*Importer to the registry, which would silently turn the
+	// backend into an auto-detect candidate for every GGUF repo. Do not read a
+	// green here as the registration being tested; that assertion lives in
+	// core/http/endpoints/localai/backend_test.go, against the /backends/known
+	// payload that actually reaches the import form.
 	It("registers no importer that would auto-match GGUF repositories", func() {
 		for _, importer := range importers.Registry() {
 			Expect(fmt.Sprintf("%T", importer)).ToNot(ContainSubstring("AudioCpp"),
diff --git a/docs/content/features/audio-cpp.md b/docs/content/features/audio-cpp.md
index 5204b7ab6..edeb76aee 100644
--- a/docs/content/features/audio-cpp.md
+++ b/docs/content/features/audio-cpp.md
@@ -160,7 +160,8 @@ Then call it like any other VAD model, as described in
 
 ## Source separation stems
 
-Separation families such as `demucs` and `roformer` produce several named outputs from one
+Separation families such as `htdemucs` and `mel_band_roformer` produce several named
+outputs from one
 run. Running inference once per stem would cost a full separation each time, so the backend
 runs **once**, writes every stem to a sibling file next to the main output, and puts the
 selected one in the response body. `params[stem]` picks which one:
@@ -181,9 +182,13 @@ ignored.
 
 ## Family notes
 
-- **Supertonic**: use the `orig` GGUF package. Its f16 and q8_0 packages mix weight dtypes
-  in a way that reaches `ggml_abort` and takes the backend process down rather than
-  returning an error, so the backend refuses those dtypes at load time with a clear message.
+- **Supertonic**: use the `orig` GGUF package, whose weights are f32. The f16 package was
+  observed to reach `ggml_concat` with mismatched operand types and take the backend
+  process down with `SIGABRT` on the first request, rather than returning an error.
+  Upstream's `docs/gguf.md` leaves supertonic's 16-bit column untested and records its
+  q8_0 as "No (unsupported weight dtype)", which says the format is unusable rather than
+  that it crashes. The backend refuses both at load time with a message naming the
+  offending tensor, so neither reaches that abort.
 - **Live transcription latency**: `AudioTranscriptionLive` needs a family advertising `asr`
   in streaming mode. At the pinned upstream revision that is `nemotron_asr`,
   `higgs_audio_stt` and `voxtral_realtime`. `higgs_audio_stt` and `voxtral_realtime` decode
diff --git a/docs/content/features/audio-to-text.md b/docs/content/features/audio-to-text.md
index 3c285bdc9..6f315ffbc 100644
--- a/docs/content/features/audio-to-text.md
+++ b/docs/content/features/audio-to-text.md
@@ -14,7 +14,7 @@ The transcription endpoint allows to convert audio files to text. The endpoint s
 - **[parakeet-cpp](https://github.com/mudler/parakeet.cpp)**: A C++/ggml port of NVIDIA NeMo Parakeet (FastConformer TDT/CTC/RNNT/hybrid). Runs quantized GGUFs on CPU or GPU, emits word-level timestamps, and supports cache-aware streaming (the `realtime_eou` model surfaces end-of-utterance events).
 - **llama-cpp**: Route transcription to any multimodal-audio GGUF model served by the `llama-cpp` backend (e.g. [Qwen3-ASR](https://huggingface.co/ggml-org/Qwen3-ASR-0.6B-GGUF), Voxtral, Qwen2-Audio). Under the hood the request is converted into a chat completion with the audio attached via the model's audio encoder - the same path the upstream llama.cpp server uses. Set `backend: llama-cpp` in the model YAML and point `mmproj` at the matching audio encoder.
 - **voxtral**: Voxtral-family models served by a dedicated backend
-- **[audio.cpp](https://github.com/0xShug0/audio.cpp)**: Multi-family GGML audio engine. Serves transcription and forced alignment from families such as nemotron, qwen3-asr, citrinet, higgs-audio-stt and voxtral-realtime, and covers diarization, VAD, TTS and source separation from the same backend. See the [audio.cpp backend]({{%relref "features/audio-cpp" %}}) page for the model options.
+- **[audio.cpp](https://github.com/0xShug0/audio.cpp)**: Multi-family GGML audio engine. Serves transcription and forced alignment from families such as `nemotron_asr`, `qwen3_asr`, `citrinet_asr`, `higgs_audio_stt` and `voxtral_realtime`, and covers diarization, VAD, TTS and source separation from the same backend. See the [audio.cpp backend]({{%relref "features/audio-cpp" %}}) page for the model options.
 
 The endpoint input supports all the audio formats supported by `ffmpeg`.
 
diff --git a/docs/content/features/audio-transform.md b/docs/content/features/audio-transform.md
index 4b3b5a88a..4f2a32dc4 100644
--- a/docs/content/features/audio-transform.md
+++ b/docs/content/features/audio-transform.md
@@ -19,9 +19,10 @@ a 1.3 M-parameter GGML-based model that performs joint AEC + noise suppression
 is a derivative of the Microsoft DeepVQE paper.
 
 Source separation and voice conversion are served by the
-[audio.cpp backend]({{%relref "features/audio-cpp" %}}): its `demucs` and
-`roformer` families produce the named stems described below, and `seed_vc`,
-`vevo2` and `miocodec` do voice conversion against a reference speaker.
+[audio.cpp backend]({{%relref "features/audio-cpp" %}}): its `htdemucs` and
+`mel_band_roformer` families produce the named stems described below, and
+`seed_vc`, `vevo2` and `miocodec` do voice conversion against a reference
+speaker.
 
 ## The mental model
 
diff --git a/docs/content/features/text-to-audio.md b/docs/content/features/text-to-audio.md
index ae428b041..a2485f3bf 100644
--- a/docs/content/features/text-to-audio.md
+++ b/docs/content/features/text-to-audio.md
@@ -750,7 +750,7 @@ curl -L http://localhost:8080/tts \
 [audio.cpp](https://github.com/0xShug0/audio.cpp) is a multi-family GGML audio engine, so
 one installed backend covers TTS (`supertonic`, `vibevoice`, `voxcpm2`, `fish_audio`,
 `pocket_tts`, `omnivoice`, `higgs_audio_tts`), voice cloning (`chatterbox`, `index_tts2`,
-`irodori_tts`, `moss`) and voice design (`qwen3_tts`, `irodori_tts`), alongside ASR, VAD,
+`irodori_tts`, `moss_tts_local`, `moss_tts_nano`) and voice design (`qwen3_tts`, `irodori_tts`), alongside ASR, VAD,
 diarization and separation.
 
 ```yaml
diff --git a/docs/content/reference/compatibility-table.md b/docs/content/reference/compatibility-table.md
index 7eab3ab81..de1cd3302 100644
--- a/docs/content/reference/compatibility-table.md
+++ b/docs/content/reference/compatibility-table.md
@@ -48,7 +48,7 @@ All backends listed here can be installed on demand from the [Backend Gallery]({
 | [Qwen3-ASR](https://github.com/QwenLM/Qwen3-ASR) | Qwen3 automatic speech recognition | CPU, CUDA 12/13, ROCm, Intel SYCL, Metal, Jetson L4T |
 | [NeMo](https://github.com/NVIDIA/NeMo) | NVIDIA NeMo ASR toolkit | CPU, CUDA 12/13, ROCm, Intel SYCL, Metal |
 | [sherpa-onnx](https://k2-fsa.github.io/sherpa/onnx/) | Sherpa-ONNX ASR (Whisper, Paraformer, SenseVoice) and TTS | CPU, CUDA 12, Metal |
-| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: transcription, forced alignment and speaker diarization (nemotron, qwen3-asr, voxtral-realtime, sortformer and more). See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
+| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: transcription, forced alignment and speaker diarization (`nemotron_asr`, `qwen3_asr`, `voxtral_realtime`, `sortformer_diar` and more). See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
 
 ## Text-to-Speech
 
@@ -76,7 +76,7 @@ All backends listed here can be installed on demand from the [Backend Gallery]({
 | [Supertonic](https://github.com/supertone-inc/supertonic) | Lightning-fast on-device multilingual TTS via ONNX | CPU |
 | [MLX-Audio](https://github.com/Blaizzy/mlx-audio) | Audio models on Apple Silicon | CPU, CUDA 12/13, Metal, Jetson L4T |
 | [liquid-audio](https://github.com/Liquid4All/liquid-audio) | LFM2 end-to-end speech-to-speech, ASR, and TTS | CPU, CUDA 12/13, ROCm, Intel SYCL, Jetson L4T |
-| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: TTS, voice cloning and voice design (chatterbox, supertonic, qwen3-tts, vibevoice and more). See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
+| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: TTS, voice cloning and voice design (`supertonic`, `vibevoice`, `qwen3_tts`, `chatterbox` and more). See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
 
 ## Music & Sound Generation
 
@@ -84,7 +84,7 @@ All backends listed here can be installed on demand from the [Backend Gallery]({
 |---------|-------------|-------------|
 | [ACE-Step](https://github.com/ace-step/ACE-Step-1.5) | Music generation from text descriptions, lyrics, or audio | CPU, CUDA 12/13, ROCm, Intel SYCL, Metal |
 | [acestep.cpp](https://github.com/ace-step/acestep.cpp) | ACE-Step 1.5 C++ backend using GGML | CPU, CUDA 12/13, ROCm, Intel SYCL, Vulkan, Metal, Jetson L4T |
-| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: music and sound generation (ace-step, stable-audio, heartmula). See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
+| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: music and sound generation (`ace_step`, `stable_audio`, `heartmula`). See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
 
 ## Image & Video Generation
 
@@ -115,7 +115,7 @@ All backends listed here can be installed on demand from the [Backend Gallery]({
 | [Silero VAD](https://github.com/snakers4/silero-vad) | Voice Activity Detection | CPU, Metal |
 | [LocalVQE](https://github.com/localai-org/LocalVQE) | Joint acoustic echo cancellation, noise suppression, and dereverberation in C/C++ using GGML | CPU, CUDA 12/13, ROCm, Intel SYCL, Vulkan, Jetson L4T |
 | [Opus](https://opus-codec.org/) | Audio codec for WebRTC / Realtime API | CPU, Metal |
-| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: voice activity detection (bundled silero-vad and marblenet-vad, no download), source separation into named stems, and voice conversion. See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
+| [audio.cpp](https://github.com/0xShug0/audio.cpp) | Multi-family GGML audio engine: voice activity detection (bundled `silero_vad` and `marblenet_vad`, no download), source separation into named stems, and voice conversion. See [audio.cpp backend](/features/audio-cpp/) | CPU, CUDA 12/13, Metal |
 
 ## Utilities & Other