Establish an incremental replication pipeline against a RESO Web API source (MLS Grid, Trestle, or Spark) using ModificationTimestamp as your watermark, running on a frequent schedule (e.g., every 5 minutes)
On each incremental pull, classify each changed record as: new listing, price reduction, status change (e.g., Active to Pending), or back-on-market by comparing incoming data to your local snapshot
Apply your buy-box filter in code against each new or changed record: property type, bedrooms, bathrooms, square footage range, year built, geography (polygon or radius), and list price range
For matching records, enqueue an evaluation job with the full listing payload; the job triggers AVM lookup, comparables pull, and offer calculation
Emit a structured alert event (webhook, queue message, or database insert) for downstream systems when a buy-box match is found, including the listing key, match timestamp, and matched criteria
Track price change history by storing each snapshot of ListPrice alongside its ModificationTimestamp so you can compute days-on-market, price reduction count, and reduction percentage
Known gotchas
ModificationTimestamp reflects any field change, not just price changes — your comparison logic must diff specific fields rather than assuming every modified record is a price change
MLS data feeds can deliver duplicate records for the same listing within a short window due to rapid successive edits; deduplicate by ListingKey before processing
Off-market listings (Withdrawn, Expired, Cancelled) still appear in incremental feeds; your pipeline must handle status transitions and remove or archive them from active inventory
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