Files
voicebox/PATCH_NOTES.md
Makinde d00e28ffda Fix: Prevent crashes when HuggingFace is unreachable
Implements offline mode patch for API stability issues:

- Add hf_offline_patch.py to monkey-patch huggingface_hub
- Force cache-only lookups before mlx_audio imports
- Create symlink from original Qwen repo to MLX community version
  when only MLX version is cached

This fixes:
- Issue #150: Internet required even with cached models
- Issue #151: API crashes when HF network fails

The patch ensures that if models are locally cached, no network
requests are made to HuggingFace during speech generation.
2026-02-22 01:57:02 -08:00

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# Voicebox Offline Mode Fix
## Problem
Voicebox crashes when generating speech if HuggingFace is unreachable, even when models are fully cached locally.
**Root Cause:**
- Voicebox downloads `mlx-community/Qwen3-TTS-12Hz-1.7B-Base-bf16` (MLX optimized version)
- But `mlx_audio.tts.load()` tries to fetch `config.json` from original repo `Qwen/Qwen3-TTS-12Hz-1.7B-Base`
- This network request fails → server crashes with `RemoteDisconnected`
**Related Issues:**
- Issue #150: "Internet connection required, even though models are downloaded?"
- Issue #151: "API Stability Issues: Model Loading Hangs and Server Crashes"
## Solution
Two-part fix:
### 1. Monkey-patch huggingface_hub (`backend/utils/hf_offline_patch.py`)
- Intercepts cache lookup functions
- Forces offline mode early (before mlx_audio imports)
- Adds debug logging for cache hits/misses
### 2. Symlink original repo to MLX version (`ensure_original_qwen_config_cached()`)
- When original `Qwen/Qwen3-TTS-12Hz-1.7B-Base` cache doesn't exist
- But MLX `mlx-community/Qwen3-TTS-12Hz-1.7B-Base-bf16` does exist
- Creates a symlink so cache lookups succeed
## Files Changed
- `backend/backends/mlx_backend.py` - Added patch imports at top
- `backend/utils/hf_offline_patch.py` - New patch module
## Testing
To test this fix:
1. Build Voicebox from source: `make build`
2. Disconnect from internet
3. Try generating speech
4. Should work without network requests
## Build Instructions
```bash
# Install dependencies
pip install -r requirements.txt
# Build the app
make build
# Or build just the server
make build-server
```
## Notes
- The patch is applied automatically when `mlx_backend.py` is imported
- Set `VOICEBOX_OFFLINE_PATCH=0` to disable the patch
- The symlink approach works because the config.json is compatible between versions
---
*Patch contributed by community*