Herman Chan

Live: https://bay-area-true-price.netlify.app Production-builder communities in eight Bay Area and San Joaquin counties: what each advertises and how its prices and incentives change over time, what those incentives are worth in dollars, and county records of earlier homes in the same community. I work in housing in the Bay Area. Buying a new home means reading dozens of builder pages and doing the loan math yourself. All of it is public, and none of it is in one place. Builders advertise rate buydowns, ARM promos and closing credits in fine print, and no two sites read alike, so buyers can't compare them. A buyer agent answers questions like "4 bedrooms, under $1.1M after incentives, ready by January", citing every home and showing the tool calls behind its answer. It covers production builders selling in seven Bay Area counties (Alameda, Contra Costa, Santa Clara, San Mateo, Solano, Sonoma and Napa) plus San Joaquin: 581 move-in-ready homes in 146 communities from 17 builders, each with a street address or lot. Sonoma shows floor plans only today. Builders whose sites show a bot challenge or need JavaScript are skipped and logged. Each incentive becomes a dollar value and each home a true-price range. In Alameda, Contra Costa and San Joaquin, that sits next to the county assessor's records for earlier homes in the community; the other five counties have listings and incentives only. It refreshes itself every morning: it re-reads every builder, re-extracts only pages whose figures changed, records each community's advertised price and incentives, and publishes. On Nov 3 the daily report showed the average discount jumping, which exposed a pricing error: Meritage's "4.99%" banner, read as a 30-year rate, was a 7/6 ARM on the builder's terms page. Fixed test-first and written up in the README. Only research existed before the Oct 26 kickoff; all code was written during the building period. The code was written with Claude Code; the product itself calls only Meta models. The demo video's narration is AI-generated with a non-Meta tool. Public data only, robots.txt honoured, no bot walls worked around.