Bounded CSV export through the same guarded query path.

Accepts the same scoped closed-catalog request as /v1/query. The server applies the same authentication, entitlement, suppression, metering, snapshot, and hard 5,000-row cap before streaming CSV. Omit-select CSV headers are the 91 canonical_fields in schema order; unheld values are empty cells. A named filter that is not held on the scoped county returns JSON empty + unavailable_fields, not CSV. CSV preflight carries bounded scope status/count headers; detailed arrays stay in query/empty JSON and the existing export audit entry. Unavailable-Count sums counties without tables and held counties missing required capability. These are not row, visited-county, field-fill or legally accessible-parcel counts. Delivery terminal states and geography availability are independent. The MCP wrapper preserves delivery status (complete/truncated/error; not-started for JSON/local honest empties), exposes delivery_complete and the bounded scope_coverage status/requested_count/bindable_count/unavailable_count, and sets complete only for exhausted delivery with valid available scope headers. Missing/unknown/contradictory available headers cannot certify completeness; error/truncation/disconnect overrides success. JSON empties retain full shared metadata and never claim completed CSV delivery. Local unresolved empties have unknown scope. No scope enumeration grants access or bypasses suppression. The in-band CSV terminal receipt includes field_notes for delivered nonblank county-field values with a material official source caveat. Notes identify the bound source and do not assign an inferred effective year. For prepared delivery, send X-PP-Delivery: artifact-v1 and a stable Idempotency-Key. A large result returns an account-bound artifact descriptor; retrieve its exact bytes through GET /v1/artifacts/{artifact_id} with the same account authorization before expiry. The path is not a bearer token.