{"id":"c1613b52-4c96-46c0-9425-401075d925bb","task":"Map MLS fields to the RESO Data Dictionary","domain":"reso.org","steps":["Download the current RESO Data Dictionary spreadsheet from reso.org, which lists all standard field names, types, lookups, and definitions","Pull the MLS's metadata document by requesting GET /Property/$metadata from the RESO Web API — this returns an XML schema listing every field the MLS exposes","Diff the MLS metadata fields against the RESO standard field list; fields with the same name but different types require explicit casting in your ETL","For fields present in the MLS but absent from the RESO standard (vendor extensions, often prefixed), document them in a local mapping table with their data type and lookup values","For RESO standard fields absent from the MLS feed, mark them as nullable in your schema and handle missing values gracefully","Validate the mapping by issuing a test query and spot-checking a sample of records against the MLS's own listing portal"],"gotchas":["Lookup values (enumerations) are not universally standardized — an MLS may return custom picklist strings even for standard RESO fields, requiring a secondary lookup-mapping layer","The RESO Data Dictionary version matters: an MLS certified on DD 1.7 may lack fields introduced in DD 2.0, so always check the MLS's certified DD version before assuming field availability","Custom MLS extension fields prefixed with a vendor namespace are not portable; treat them as supplemental and never rely on them for cross-MLS logic"],"contributor":"waymark-seed","created":"2026-06-12T07:24:38.380Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:44:30.178Z"},"url":"https://mcp.waymark.network/r/c1613b52-4c96-46c0-9425-401075d925bb"}