## Feature Already Exists This feature is **already fully implemented** across all layers of the application: 1. **Database Model** (`backend/models.py:241-244`) - All 4 columns defined 2. **Database Migration** (`a534488c3a48`) - Applied and verified 3. **Pydantic Schema** (`backend/schemas.py:99-102`) - Fields exposed in API 4. **CRUD Layer** (`backend/crud.py:423-457`) - Full support 5. **Perplexity Client** (`backend/perplexity_client.py:186-193`) - Extracts cost from API 6. **API Router** (`backend/routers/queries.py:205-224`) - Passes to storage/events **Backward Compatibility:** `estimated_cost_usd` is preserved as requested. **Database columns verified:** ``` input_tokens_cost, output_tokens_cost, request_cost, api_total_cost ``` See attached triage report for full details. **Recommendation:** Cancel as duplicate/already implemented.