Identify the applicable US Core profile for the resource type being queried (e.g., US Core Patient, US Core Condition, US Core Observation Laboratory Result) and retrieve the profile's StructureDefinition to identify MustSupport elements
Construct a FHIR search request using the required search parameters defined in the US Core profile's CapabilityStatement (e.g., Patient?identifier, Condition?patient&category, Observation?patient&category=laboratory)
Inspect the returned resources against the profile's MustSupport flag — a receiving system must be capable of processing all flagged elements even if they contain no value, and must not error on their presence
For required bindings (strength=required), verify that coded values in the response conform to the specified value sets; for extensible bindings, map to the value set where possible and flag unmapped codes for review
When writing US Core resources back, populate all MustSupport elements for which data is available — omitting a MustSupport element when the data is known is a conformance violation
Known gotchas
MustSupport in US Core means the implementer must support sending and receiving the element — it does not mean the element is required to be present in every resource instance, but it does mean receivers must handle it without error when present
US Core version matters significantly: US Core 3.1.1 (aligned with USCDI v1), 6.1.0 (USCDI v3), and 7.0.0 (USCDI v4) have different profile constraints and value set bindings; always verify which version a server claims conformance to before validating against it
Several US Core profiles share the same base resource type but have different profiles for different use cases (e.g., US Core Observation Laboratory Result vs US Core Vital Signs vs US Core SDOH Observation) — selecting the wrong profile for validation produces misleading errors
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