Two companion documents make up the English-to-X12 bridge. Both are written so an X12-novice developer and an EDI engineer get what they need from the same page — every entry has both a plain-English summary and the underlying X12 reference.
- mappings.md — English-to-X12 lookup for the SDK's classes, methods, and properties. Start here if you're integrating the library and want to understand which X12 concept each API surface maps to.
- diagnostics.md — Plain-English reference for every validation diagnostic the engine can emit, with severity, category, X12-jargon detail, common causes, and remediation. Start here if a validation report surfaced a code you don't recognize.
Stable contract: diagnostic codes (TX_HL_ORPHAN, etc.) and API
method names do not change after they ship. Diagnostic messages and
documentation prose may be reworded over time for clarity — don't
pattern-match against them programmatically.