Review the Da Vinci ATR IG (hl7.org/fhir/us/davinci-atr) to understand the Member Attribution List workflow: a payer creates and maintains a FHIR Group resource representing the attributed patient population for a value-based care contract.
Retrieve the attribution list: providers query GET [base]/Group?characteristic-value=[contract-id] or use a payer-defined identifier to locate the relevant Group resource representing their attributed population.
Use $export on the Group to retrieve the full member list as NDJSON: GET [base]/Group/[id]/$export with _type=Patient to obtain Patient resources for all attributed members, or include additional types for clinical data.
Implement the ATR $davinci-data-export operation if supported by the payer: this Da Vinci-specific operation exports attribution-related resources (Group, Patient, Coverage, and optionally clinical resources) as a coordinated bulk export.
Process incremental updates: use the _since parameter on subsequent exports to retrieve only members added or removed from the attribution list since the last sync, avoiding full re-download on every refresh cycle.
Reconcile the attribution list with the provider's patient panel: identify newly attributed members (to initiate outreach), members removed from attribution (to close care gaps), and members whose attribution details have changed.
Known gotchas
ATR Group resources may contain tens of thousands of members — implementers must use Bulk Data export rather than expanding the Group via FHIR search, which would be impractical at scale and may be blocked by server-side limits.
Member attribution in value-based care is often contractually sensitive; payers may restrict Group access so that only the contracting provider organization can retrieve the Group — ensure B2B authentication is set up correctly before attempting Group queries.
ATR lists may include attributed members who are not yet seen by the provider; the provider's EHR may not have a Patient record for every attributed member — the provider must handle 'new' patients from the ATR list without assuming an existing local patient record.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp