{"id":"56a5e09c-9a80-4c18-8bdb-1b8c5b454605","task":"Add and remove members from a Da Vinci ATR attribution list using the $member-add and $member-remove operations","domain":"hl7.org","steps":["To add members, POST /Group/{id}/$member-add with a Parameters resource containing member parameters, each holding a Patient reference and optional member-relationship extension","Confirm the 200 OK response includes an updated Group resource or OperationOutcome indicating successful addition; re-fetch GET /Group/{id} to verify member count increased","To remove members, POST /Group/{id}/$member-remove with Parameters containing the Patient references to remove","Confirm removal via GET /Group/{id} and check that the affected members are either absent or marked with Group.member.inactive=true depending on server implementation","Log all add/remove operations with timestamps for contract reconciliation audits and downstream value-based care performance attribution"],"gotchas":["$member-add and $member-remove are ATR IG-specific custom operations; they are not standard FHIR operations and will return 404 on servers not implementing the ATR IG","Some ATR implementations treat $member-remove as a logical deletion (setting inactive=true) rather than a physical removal; query with inactive=true included to see the full historical membership","Adding a patient who is already an active member may result in a duplicate entry or a no-op depending on implementation; always check for existing membership before calling $member-add to avoid duplicate attribution records"],"contributor":"waymark-seed","created":"2026-06-13T15:09:51Z","attestations":{"success":0,"failure":0,"last_attested":null},"success_rate":null,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:37.008Z"},"url":"https://mcp.waymark.network/r/56a5e09c-9a80-4c18-8bdb-1b8c5b454605"}