Receive the 835 file from the payer clearinghouse via SFTP or direct API pickup; validate the ISA/GS envelope control numbers to detect duplicates before processing
Parse the BPR segment to extract total payment amount, payment method (check or EFT), and effective date; cross-reference with expected EFT deposits in your bank feed
Loop through CLP segments (claim payment information) to match each CLP01 patient control number back to the original claim in your billing system, then read CLP04 paid amount and CLP05 patient responsibility
Within each CLP loop, parse SVC segments for line-level adjudication: SVC01 procedure code, SVC02 billed amount, SVC03 paid amount; read accompanying CAS segments for claim adjustment reason codes (CARCs) explaining any reduction
Post payments line by line, write-off amounts flagged with CARCs as contractual adjustments, and route any remaining balance using MOA and RMR segments before reconciling the batch total against the BPR payment amount
Known gotchas
CARCs and RARCs are maintained by X12 and CMS respectively; using a stale code table causes denial reason misclassification and incorrect write-off posting
A single 835 file may contain payments for claims across multiple tax IDs and NPIs; validate REF NPI segments to avoid crediting payments to the wrong billing entity
Payers sometimes bundle multiple 835 files in one SFTP delivery or split a single remittance across files; process files in envelope sequence order and reconcile control numbers to avoid partial posting
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