---
title: "A game in development"
url: "https://toddpaulbrownjr.com/builds/game-in-development/"
author: "Todd Paul Brown Jr."
description: "An action RPG in Unreal Engine, built with Claude Code: 81,707 lines of gameplay C++, a playable build under playtest, not shipped. The numbers underneath."
kind: "build"
updated: "2026-09-26T02:50:14+00:00"
---

# A game in development

## What it is

An action RPG in Unreal Engine 5.8. It's **in development**: there's a playable packaged build, I'm playtesting it on a controller, and it is not shipped. Right now the work is cleanup, truthful tests and validated data, not new content. It stays unnamed here until it's closer to done.

## Why it's on this site

Because the infrastructure turned out to be the interesting part. I measured what's underneath the game on 20 September, and the numbers say more about how an agent-driven build actually runs than any finished feature would.

The claim isn't "AI built a game." It's how much tested engineering a few hundred prompts of direction can carry. The agent writes the code, the tests and the documentation. I direct, decide, buy things and playtest.

## How it's built

I ran 26 orchestrating Claude Code sessions. They spawned 519 subagent conversations, which out-produced the main thread 7.8 to 1 by output volume.

My side of it: 157 prompts, about 53,000 typed characters of direction, in the two weeks when three-quarters of that C++ was written. The other quarter came from a two-day scaffold in July whose transcripts didn't survive, so I can't count those prompts. I checked that proportion with `git blame` rather than guessing.

The documentation is bigger than the code: 104,912 lines of Markdown against 81,707 lines of gameplay C++, 1.28 lines of docs per line of code. The largest share of it (about 40%) exists so the agent can read itself back into context at the start of a session. Most of this project's documentation has no human reader at all.

What the agent couldn't do:

- 250 recorded product decisions
- purchasing and licensing calls
- installing the engine
- adopting a design document wholesale
- playtesting with a controller in hand

## What broke

**Nine weeks of nothing.** The commit history shows two days of scaffolding in July, then 63 days with zero commits, then 257 commits in two weeks. From the outside that looks abandoned. It wasn't: the engine version I was on lacked a capability the project needed, and work resumed when the next version shipped.

**Tests that couldn't see the game.** 30,069 lines of automated tests, and the defects that mattered most still showed up with a controller in my hands.

**My own stats report drifted.** The first draft of the measurement report had understated commits, decision entries and subagent counts, and a pattern-matching bug counted blank answers in my decision inbox as answered. A fresh-context check and a second pass caught both before anything was published.

## Receipts

| Figure | What | Source |
|---|---|---|
| 81,707 | lines of gameplay C++, 536 files | dev-stats report, 2026-09-20, measured |
| 30,069 | lines of automated-test C++ | same |
| 291 | commits in 79 days | same |
| 519 | subagent conversations under 26 sessions | same, transcript window only |
| 157 | prompts in the two weeks that hold ~75% of the C++ | same + `git blame`, 2026-09-21 |
| 1.28 | lines of docs per line of production C++ | same |

All measured. More on the [receipts page](/receipts/).