Non-modal Epic cluster: 135 of 739 production endpoints (18%) deploy this shape, concentrated in CA (12), TX (8), OH (8). This cluster advertises 47 US Core 6.1 profiles in its CapabilityStatement, distinguishing it from the modal cluster.
A CapabilityStatement shape cluster groups production FHIR endpoints by the exact CapabilityStatement they serve at runtime. Epic publishes one reference CapabilityStatement, but production hospitals deploy several distinct shapes of it — each cluster is one of those shapes.
ff28bdd6ad43772b…AllergyIntolerance · CarePlan · CareTeam · Condition · Coverage · Device · DiagnosticReport · DocumentReference · Encounter · Goal · Immunization · Location · Medication · MedicationDispense · MedicationRequest · Observation · Organization · Patient · Practitioner · PractitionerRole · Procedure · Provenance · QuestionnaireResponse · RelatedPerson · ServiceRequest · Specimen
Account · AdverseEvent · Appointment · Binary · BodyStructure · Claim · Communication · ConceptMap · Consent · Contract · DeviceRequest · DeviceUseStatement · Endpoint · EpisodeOfCare · ExplanationOfBenefit · FamilyMemberHistory · Flag · Group · ImagingStudy · ImmunizationRecommendation · List · Measure · MeasureReport · Media · MedicationAdministration · NutritionOrder · Questionnaire · RequestGroup · ResearchStudy · ResearchSubject · Substance · Task · ValueSet
CA (12) · TX (8) · OH (8) · NY (7) · MA (5) · PA (5) · MI (5) · IL (4) · WA (4) · IN (3)
Empty-result Bundles carry a 'mode=outcome' OperationOutcome entry, not an empty entry array Match-counting code MUST filter Bundle.entry by `entry.search.mode != 'outcome'` and `resource.resourceType != 'OperationOutcome'`. Otherwise zero-result searches appear as one-result searches, and downstream loops process the OperationOutcome as if it were a clinical resource — silent data corruption.
From the public Epic overlay finding sweep (2026-04-26). Full vendor overlay has 22 findings with verbatim quotes and source URLs.
This outlier cluster has too few production endpoints for us to host a dedicated mock under /v/cluster/epic-cluster-B/ today. The modal Epic cluster is the wire shape that most production deployments use — that's the right starting point for integration testing.
Compatible with Epic's published FHIR R4 CapabilityStatement (Epic February 2026 release, fetched 2026-04-26). Not affiliated with or endorsed by Epic Systems Corporation. Trademarks of Epic Systems Corporation are used for identification only. Synthetic sandbox modeled after observed Epic deployment shapes. Not affiliated with the vendor or any listed hospital. Trademarks used for identification only.