---
title: "Spinel — Ruby AOT Compiler"
description: "Ruby creator Matz is using Claude Code to build an ahead-of-time compiler for Ruby. The interesting automation is implementation in service of unusually deep human judgment."
author: "Pau Friedman"
kind: "link"
published_at: "2026-04-24"
url: "https://pau.fm/blog/2026/04/24/spinel-ruby-aot-compiler"
markdown_url: "https://pau.fm/blog/2026/04/24/spinel-ruby-aot-compiler.md"
canonical_url: "https://pau.fm/blog/2026/04/24/spinel-ruby-aot-compiler"
external_url: "https://github.com/matz/spinel"
---

# [Spinel — Ruby AOT Compiler](<https://github.com/matz/spinel>)

Matz, the inventor of Ruby, is using Claude Code to build an ahead-of-time compiler for his own
language. Spinel performs whole-program type inference, generates C, and produces standalone native
executables. This is much more interesting than a generic claim that AI can code: a person with an
extremely precise model of the problem is using a machine to pursue a compiler that would otherwise
require too much implementation work.

The division of labor matters. Claude did not invent Ruby or decide which kinds of dynamism to
sacrifice. It made the language designer’s backlog cheaper.