---
estimated_steps: 4
estimated_files: 3
skills_used: []
---

# T01: Add per-stage model config fields and stage config helper

1. Add 8 per-stage fields to Settings: llm_stage{2-5}_model (Optional[str], default None) and llm_stage{2-5}_modality (str, default 'chat')
2. Add _get_stage_config(stage_num) helper to stages.py
3. Update .env.example with new vars and comments
4. Verify Settings loads correctly with and without stage-specific vars

## Inputs

- `backend/config.py`

## Expected Output

- `backend/config.py (updated)`
- `backend/pipeline/stages.py (_get_stage_config helper)`
- `.env.example (updated)`

## Verification

cd backend && python3 -c "from config import Settings; s = Settings(); print(s.llm_stage2_model, s.llm_stage2_modality)"
