ARCNM Cost Drivers
arcnm_cost_driversRead-onlyIdempotent
Rank the top cost drivers of a calculation (largest first) so you can target a redesign or re-quote — each with its cost, its share of the unit cost, and why it is costly. This is the FEATURE axis: which pocket, hole or slot the money goes into, the view you act on to change the PART. For the CATEGORY axis — which cost line (material, setup, machine, labour, …) it sits in, and the per-machine, per-clamping, per-work-element tiers beneath it — use arcnm_cost_breakdown, which serves the itemised cost sheet. Neither derives the other: one feature's cost is spread across several cost lines, and one cost line covers many features. Read-only.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| top_n | No | ||
| calculation_id | Yes |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| status | Yes | ||
| drivers | No | ||
| currency | No | The calculation's currency; unit_cost and every driver's cost are stated in it. | |
| guidance | Yes | ||
| unit_cost | No | Unit cost per part BEFORE the cost-sheet surcharges — the cost the drivers are shares of. The price to quote is arcnm_explain_cost's offer_price. | |
| needs_review | No | True when this calculation is flagged for human review — its unit cost is not a quote yet. | |
| calculation_id | Yes | ||
| inputs_changed_since_run | No | Null when this price reflects every input on its part revision. Otherwise {roles, corrections, latest_at}: files attached and corrections applied to the part after the run read its inputs, which a new calculation reads and this one did not. | |
| attributed_cost_share_pct | No | Share of unit cost (0–100) the named drivers actually explain — so you don't over-trust the top-N as the whole story. The rest is shared/overhead cost not attributable to one feature. | |
| environment_changed_since_run | No | Null when this price was computed on its costing environment as it stands. Otherwise {latest_at}: the environment was edited after the run read it, and a new calculation prices with the current setup while this result does not. |