# Data Mapping

<!-- guide: Field-level transformation between systems. Large mappings go to a
     machine-checkable file in contracts/ and are referenced here. Remove guides. -->

## Source and Target

| Mapping | Source (owner) | Target (owner) | Direction | Trigger |
| --- | --- | --- | --- | --- |

## Field Mapping

| Target field | Source field(s) | Transformation | Unit / currency / scale | Nullability | Default | Validation | On failure |
| --- | --- | --- | --- | --- | --- | --- | --- |

## Invariants

<!-- guide: Conservation rules that must hold after mapping, e.g. "total = sum of
     positions + cash; each money unit counted once", sign conventions, rounding
     point. Each invariant references the spec requirement it protects. -->

## Double-counting and Classification Risks

<!-- guide: Every source record type that could fall into two target aggregates,
     and the rule that assigns it to exactly one. -->

## Transformation Errors

## Open Questions