What this site is

I’m Herman Chan. I work in acquisitions at Haven Realty Capital, sourcing and underwriting single-family rental and build-for-rent deals across the Sunbelt — Phoenix, Houston, Atlanta, Dallas, the Tampa exurbs. The job is half deal flow and half spreadsheet: read offering memoranda, build models, pull rent comps, understand submarkets, decide whether something pencils. I’ve been doing it long enough to know which steps are actually underwriting — and which are just moving data from one system to another.

The unusual part: I build AI tools — for my own underwriting work. I’m not the one writing the code. I scope what each tool needs to do, decide how to split work between deterministic scripts and an LLM, pick the model, and direct Claude through the build. I’m not a software engineer pretending to be in real estate, and I’m not an analyst pasting prompts into a chat window. I’m the underwriter making the architecture decisions; the code itself is Claude’s. The wins are specific: a one-page summary that used to take two hours now takes fifteen minutes; T-12 and rent-roll skills that each replace a couple hours of Excel work with a single prompt.

This site is where I write up the design decisions behind those tools. What was hard, what I tried first and abandoned, what I’d do differently if I started over. Short posts, one idea each, dated. Builder notes — not tutorials, not industry takes, not predictions about where AI is going.

The angle is simple: I’m the underwriter, and the tools I write about are the ones I run on real deals every week. The engineering detail lives here; CRE-flavored summaries go to my LinkedIn.