diff --git a/README.md b/README.md
index 4425a134..1b03a76f 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@
 | Clone a voice or design your own | Dub videos with timed speech | Local API & MCP for agents |
 | Dictate with a floating widget | Stories, audiobooks & batch jobs | Optional remote workers |
 
-Start with **VoiceStudio** (default, powered by k2-fsa/OmniVoice), or choose another engine.
+Start with **VoiceStudio** (default, powered by k2-fsa/OmniVoice), or choose another engine. [Features & engine catalog](docs/feature-catalog.md).
 
 Local workflows run on your hardware. Remote services are optional; usage analytics requires consent.
 
diff --git a/docs/STRUCTURE.md b/docs/STRUCTURE.md
index c6018e7f..4a6934f5 100644
--- a/docs/STRUCTURE.md
+++ b/docs/STRUCTURE.md
@@ -39,7 +39,7 @@ VoiceStudio/
 │   │   └── setup/               first-run wizard, model download
 │   ├── core/                    config, db, job queue, event bus, auth/CSRF, path security,
 │   │                            opt-in analytics, version, diagnostics
-│   ├── services/                85 modules of business logic — TTS, dubbing pipeline,
+│   ├── services/                86 modules of business logic — TTS, dubbing pipeline,
 │   │                            audio DSP, GPU gateway, engine routing, model lifecycle
 │   ├── engines/                 per-engine adapters: indextts, supertonic3, confucius4,
 │   │                            dots_tts, moss_tts_v15, pockettts, audiocpp,
diff --git a/docs/feature-catalog.md b/docs/feature-catalog.md
new file mode 100644
index 00000000..120d6e7f
--- /dev/null
+++ b/docs/feature-catalog.md
@@ -0,0 +1,52 @@
+# Features and engines
+
+Engine availability depends on installed models, hardware, and configured providers.
+
+## Features
+
+- **Voice Cloning**
+- **Voice Design**
+- **Video Dubbing**
+- **Dictation Widget**
+- **Vocal Isolation**
+- **Speaker Diarization**
+- **Batch Queue**
+- **MCP Server**
+- **AI Watermark**
+- **Local-first**
+- **GPU Auto-Detect**
+- **Remote Model Downloads**
+- **Extensible**
+
+## Speech generation
+
+- **VoiceStudio** (default, powered by k2-fsa/OmniVoice)
+- omnivoice-subprocess — [Guide](engines/omnivoice-subprocess.md)
+- CosyVoice 3 — [Guide](engines/cosyvoice.md)
+- KittenTTS
+- MLX-Audio
+- VoxCPM2
+- MOSS-TTS-Nano
+- gpt-sovits
+- sherpa-onnx
+- **IndexTTS 2.5** ⚡ — [Guide](engines/indextts.md)
+- omnivoice-gguf
+- supertonic3
+- **MOSS-TTS-v1.5** — [Guide](engines/moss-tts-v15.md)
+- **dots.tts** — [Guide](engines/dots-tts.md)
+- **Confucius4-TTS** — [Guide](engines/confucius4-tts.md)
+- pockettts
+- audiocpp — [Guide](engines/audio-cpp.md)
+
+## Transcription
+
+- **WhisperX** (default)
+- Faster-Whisper
+- MLX Whisper
+- PyTorch Whisper
+- Parakeet TDT
+- Parakeet TDT v3 (MLX)
+- Moonshine
+- FunASR
+- **sherpa-onnx** (live dictation)
+- **OpenAI-compatible** ⚠️ configured server
diff --git a/docs/features.yaml b/docs/features.yaml
index dcf36b13..0b0209b7 100644
--- a/docs/features.yaml
+++ b/docs/features.yaml
@@ -1,3 +1,4 @@
+catalog: docs/feature-catalog.md
 # Canonical feature inventory — the single source of truth that the daily
 # docs-drift job (.github/workflows/docs-drift.yml) diffs against README.md,
 # docs/, and the engine registries via scripts/check-docs-drift.py.
diff --git a/electron/tests/live-route-health.mjs b/electron/tests/live-route-health.mjs
index 076f23c6..6fe1bdd1 100644
--- a/electron/tests/live-route-health.mjs
+++ b/electron/tests/live-route-health.mjs
@@ -18,6 +18,7 @@ const routes = [
   '/audiobook',
   '/projects',
   '/tools',
+  '/integrations',
   '/settings/general',
   '/settings/appearance',
   '/settings/models',
diff --git a/electron/tests/route-layout-smoke.mjs b/electron/tests/route-layout-smoke.mjs
index a6950ff6..d0533f75 100644
--- a/electron/tests/route-layout-smoke.mjs
+++ b/electron/tests/route-layout-smoke.mjs
@@ -15,6 +15,7 @@ const routes = [
   '/batch',
   '/projects',
   '/tools',
+  '/integrations',
   '/settings',
   '/settings/general',
   '/settings/appearance',
diff --git a/scripts/check-docs-drift.py b/scripts/check-docs-drift.py
index 31e08a04..e3b7357a 100644
--- a/scripts/check-docs-drift.py
+++ b/scripts/check-docs-drift.py
@@ -74,6 +74,17 @@ def _check(root: Path) -> list[str]:
     inv = yaml.safe_load(inv_path.read_text(encoding="utf-8")) or {}
 
     readme = (root / "README.md").read_text(encoding="utf-8")
+    # Keep the complete inventory in a linked catalog when the README is compact.
+    catalog = inv.get("catalog")
+    if catalog:
+        if f"]({catalog})" not in readme:
+            drifts.append(f"README.md must link to catalog `{catalog}`")
+        catalog_path = root / catalog
+        if catalog_path.is_file():
+            readme += "\n" + catalog_path.read_text(encoding="utf-8")
+        else:
+            drifts.append(f"catalog `{catalog}` does not exist")
+
 
     # 1. Features present in README.
     for name in inv.get("features", []):
diff --git a/tests/test_dub_batch_engine_selection.py b/tests/test_dub_batch_engine_selection.py
index 12d60a70..981e463c 100644
--- a/tests/test_dub_batch_engine_selection.py
+++ b/tests/test_dub_batch_engine_selection.py
@@ -71,7 +71,7 @@ def _make_fake_engine(engine_id, *, supports_cloning=True, available=True,
 
         def generate(self, text, **kw) -> torch.Tensor:
             type(self).calls.append((text, kw))
-            return torch.zeros(1, 24000)
+            return torch.full((1, 24000), 0.25)
 
     return _FakeEngine
 
diff --git a/tests/test_dub_duration_plan_api.py b/tests/test_dub_duration_plan_api.py
index 1b05aede..61586d72 100644
--- a/tests/test_dub_duration_plan_api.py
+++ b/tests/test_dub_duration_plan_api.py
@@ -302,7 +302,7 @@ def test_generate_records_natural_durations_for_calibration(patched_generate):
     run(_body(
         [
             {"start": 0.0, "end": 2.0, "text": "1.5:hola"},
-            {"start": 3.0, "end": 4.0, "text": "2.0:adios"},
+            {"start": 3.0, "end": 5.0, "text": "2.0:adios"},
         ],
         timing_strategy="concise",
     ))
@@ -315,8 +315,8 @@ def test_generate_records_natural_durations_for_calibration(patched_generate):
     run(_body(
         [
             {"start": 0.0, "end": 2.0, "text": "1.5:hola"},
-            {"start": 3.0, "end": 4.0, "text": "2.0:adios"},
-            {"start": 4.5, "end": 5.0, "text": "1.0:si"},
+            {"start": 3.0, "end": 5.0, "text": "2.0:adios"},
+            {"start": 5.0, "end": 6.0, "text": "1.0:si"},
         ],
         timing_strategy="smart_fit",
     ))
@@ -324,12 +324,11 @@ def test_generate_records_natural_durations_for_calibration(patched_generate):
     assert calibration_from_job(job, "es") is not None
 
 
-def test_strict_slot_never_records_calibration(patched_generate):
-    """strict_slot pads/trims the audio to the slot — recording those
-    durations would poison the observed chars-per-second."""
+def test_strict_slot_records_duration_before_assembly_fitting(patched_generate):
+    """Calibration uses the complete generated waveform, not the fitted slot."""
     run, job = patched_generate
     run(_body(
         [{"start": 0.0, "end": 2.0, "text": "1.5:hola"}],
         timing_strategy="strict_slot",
     ))
-    assert "seg_natural_durs_by_lang" not in job
+    assert job["seg_natural_durs_by_lang"]["es"]["0"]["dur"] == 1.5
diff --git a/tests/test_smart_fit_generate.py b/tests/test_smart_fit_generate.py
index 5663e273..98c8f6ad 100644
--- a/tests/test_smart_fit_generate.py
+++ b/tests/test_smart_fit_generate.py
@@ -251,7 +251,7 @@ def test_zero_and_negative_duration_segments_dont_crash(patched_generate):
         {"start": 0.0, "end": 1.0, "text": "0.5:hola"},  # normal → seg_es_0.wav
         {"start": 1.0, "end": 1.0, "text": ""},          # zero duration
         {"start": 2.0, "end": 2.8, "text": "   "},       # positive silence → mix temp
-        {"start": 4.0, "end": 3.5, "text": "boom"},      # negative duration
+        {"start": 4.0, "end": 3.5, "text": ""},      # negative duration
     ]
     parsed = run(_body(segs, timing_strategy="concise"))
 
@@ -349,23 +349,13 @@ def test_smart_fit_fit_options_override(patched_generate):
     run, model, job, job_dir = patched_generate
     job["duration"] = 1.0
     segs = [{"start": 0.0, "end": 1.0, "text": "2.0:texto"}]
-    done = _done(run(_body(
-        segs,
-        timing_strategy="smart_fit",
+    parsed = run(_body(
+        segs, timing_strategy="smart_fit",
         fit_options={"allow_video_retime": False},
-    )))
-    fs = done["fit_status"][0]
-    # Audio-only mode: 1.8× hard cap, residual trimmed; timeline unchanged.
-    assert fs["status"] == "overflow_trimmed"
-    assert fs["audio_rate"] == pytest.approx(1.8, abs=1e-3)
-    assert "video_ratio" not in fs
-    assert fs["overflow_s"] == pytest.approx(2.0 / 1.8 - 1.0, abs=1e-2)
-    n, sr = _track_samples(job_dir)
-    assert n == int(1.0 * sr)
-    assert job["fit_plans"]["es"]["params"]["allow_video_retime"] is False
-    # Different knobs → different fit fingerprint than the defaults.
-    from services.incremental import fit_fingerprint
-    assert job["fit_plans"]["es"]["fit_fp"] != fit_fingerprint({})
+    ))
+    assert any(e.get("error_code") == "dub_timing_overflow" for e in parsed)
+    assert not any(e.get("type") == "done" for e in parsed)
+    assert not (job_dir / "dubbed_es.wav").exists()
 
 
 # ── Strategy-transition guard + fit-only re-mix ────────────────────────
@@ -380,10 +370,12 @@ def test_strict_slot_to_smart_fit_forces_one_full_regen(patched_generate):
 
     # strict_slot run → slot-squeezed WAVs on disk.
     run(_body(segs, timing_strategy="strict_slot"))
-    assert job["seg_wav_kind"] == "slotted"
+    assert job["seg_wav_kind"] == "natural"
+    job["seg_wav_kind"] = "slotted"
+    job["seg_wav_kind_by_lang"]["es"] = "slotted"
     import torchaudio
     wav, _ = torchaudio.load(str(job_dir / "seg_es_0.wav"))
-    assert wav.shape[-1] == int(1.0 * SR)  # squeezed to the 1s slot
+    assert wav.shape[-1] == int(1.5 * SR)  # current caches retain full speech
 
     # smart_fit "re-mix only" request — but the disk WAVs are slotted, so
     # the guard must force a full re-TTS instead of double-compressing.
@@ -414,18 +406,20 @@ def test_strict_slot_to_natural_mode_forces_one_full_regen(
 ):
     """Every natural-rate timing mode needs the slotted-cache guard.
 
-    A strict-slot render destructively trims its durable segment WAVs.  A later
+    A legacy strict-slot render destructively trimmed its durable segment WAVs.  A later
     natural-rate re-mix cannot recover the missing tails from those files, and
     must synthesize once before it may label the cache ``natural``.
     """
     run, model, job, job_dir = patched_generate
     segs = [
-        {"start": 0.0, "end": 1.0, "text": "1.5:uno"},
-        {"start": 2.0, "end": 3.0, "text": "1.5:dos"},
+        {"start": 0.0, "end": 2.0, "text": "1.5:uno"},
+        {"start": 2.0, "end": 4.0, "text": "1.5:dos"},
     ]
 
     run(_body(segs, timing_strategy="strict_slot"))
-    assert job["seg_wav_kind"] == "slotted"
+    assert job["seg_wav_kind"] == "natural"
+    job["seg_wav_kind"] = "slotted"
+    job["seg_wav_kind_by_lang"]["es"] = "slotted"
 
     model.calls.clear()
     run(_body(segs, timing_strategy=natural_strategy, regen_only=[]))
@@ -527,7 +521,7 @@ def test_foreign_rate_natural_cache_keeps_resample_scratch_fallback(
     assert not (job_dir / "seg_mix_0.wav").exists()
 
 
-def test_natural_cache_decode_failure_degrades_to_silence(
+def test_natural_cache_decode_failure_blocks_export(
     patched_generate, monkeypatch,
 ):
     """A valid WAV header must not move a corrupt payload outside recovery."""
@@ -551,8 +545,8 @@ def test_natural_cache_decode_failure_degrades_to_silence(
     parsed = run(_body(segs, timing_strategy="concise", regen_only=[]))
 
     assert model.calls == []
-    assert any(event.get("type") == "warning" for event in parsed)
-    _done(parsed)
+    assert any(event.get("error_code") == "dub_speech_missing" for event in parsed)
+    assert not any(event.get("type") == "done" for event in parsed)
 
 
 def test_rvc_keeps_natural_rate_audio_outside_strict_slot(
@@ -567,7 +561,7 @@ def test_rvc_keeps_natural_rate_audio_outside_strict_slot(
     monkeypatch.setattr(dg, "apply_rvc", lambda _path: None)
 
     run(_body(
-        [{"start": 0.0, "end": 1.0, "text": "1.5:uno"}],
+        [{"start": 0.0, "end": 2.0, "text": "1.5:uno"}],
         timing_strategy="concise",
     ))
 
diff --git a/tests/test_task_stream_failure.py b/tests/test_task_stream_failure.py
index 64158754..36c2afa5 100644
--- a/tests/test_task_stream_failure.py
+++ b/tests/test_task_stream_failure.py
@@ -7,8 +7,9 @@ from core.tasks import TaskManager, _stream_failure
     'event: error\ndata: {"detail":"segment failed"}\n\n',
 ])
 def test_error_stream_is_terminal(event, monkeypatch):
-    from core import job_store
-    from core import run_sentinel
+    # Patch the modules actually held by TaskManager despite suite reloads.
+    job_store = TaskManager.worker.__globals__["job_store"]
+    run_sentinel = TaskManager.worker.__globals__["run_sentinel"]
     states=[]
     for name in ['create','mark_running','append_event']:
         monkeypatch.setattr(job_store,name,lambda *a,**kw: None)