Construct a CoverageEligibilityRequest resource referencing the patient, their Coverage, and the requesting provider
POST to the payer's CoverageEligibilityRequest endpoint or, if the payer uses an X12 gateway, map the FHIR resource fields to the X12 270 ISA/GS envelope, Loop 2000, and Loop 2010 segments
Map Coverage.subscriberId to the X12 270 subscriber ID segment and Coverage.payor to the payer identification loop
Receive the CoverageEligibilityResponse (or X12 271 mapped to it) and extract benefit details from the insurance.item elements
Surface in-network status, copay, deductible, and out-of-pocket maximum from the benefit items to the point-of-care workflow
Known gotchas
X12 270/271 uses a date format (CCYYMMDD) that differs from FHIR's date format (YYYY-MM-DD); date conversion errors are a common source of rejected transactions
The X12 service type code (loop 2110 EB01) has no direct FHIR equivalent field; the mapping is specified in implementation guides but varies by payer, requiring payer-specific configuration
CoverageEligibilityRequest.purpose must include the appropriate code ('benefits', 'discovery', 'validation') since payers may reject requests with an unrecognized or missing purpose code
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