---
title: "About · Chappell AI"
description: "Bill Chappell is a retired software developer who directed coding agents to build GAAPcore, a US-GAAP accounting core."
url: https://chappellai.us/about/
---

# About

I'm Bill Chappell. I'm a retired software developer. I spent my career integrating large systems for large companies, much of it in software for the radiopharmaceutical industry, including at Sofie Biosciences.

I built GAAPcore by directing coding agents. I spent my own time on the parts that decide whether software can be trusted: the specs, the data model, and the review.

## How it was built

**Spec first.** Every transaction type has a written spec before any code: the business trigger, the journal entries, the FIFO effects, every validation with its error code, how it reverses, and the US GAAP notes. There are 129 of them now.

**An independent review gate on every migration.** Each of the 107 schema migrations went to a separate reviewer before it merged. The reviewer's job was to break it. Of the 31 migrations logged since early October, 20 came back on HOLD at least once, each with a concrete way to make the books wrong, and were fixed and reviewed again.

**Thousands of automated checks.** Every rule has a test that proves it refuses what it should. The database suites post realistic documents, try to break each rule, and roll back. The API has its own tests on top.

**Gaps written down, not hidden.** Every place the schema doesn't yet do what a spec needs is a numbered gap with a decision next to it. There are 402 so far.

From early October, under a written charter, I took myself out of the day-to-day loop. The agent chose the next item, put it through the review gate, and merged only on approval. I read the log and set direction.

## Why I'm writing here

I'm looking for a few developers who build business software with coding agents and want an accounting core they don't have to write. If that's you, [request access](https://chappellai.us/access/). If you'd rather have the console built for you, [I can help with that too](https://chappellai.us/work-with-me/).

![Bill Chappell, smiling, with short grey hair, in a dark jacket and light blue open-collar shirt.](https://chappellai.us/img/bill-480.webp)