AI for Legacy Code

Every developer inherits a system written by someone who has since moved on, often with no tests, no comments, and a tangled architecture that nobody fully understands. This book shows you how to use AI as a partner to decode those systems. You will learn to prompt AI assistants to extract hidden logic, reconstruct data flows, and surface assumptions buried in old code. Through practical, repeatable techniques, you will transform silent monoliths into explorable, documented systems without betraying the craft of software. Each chapter covers a specific scenario: reading error-prone forensic dumps, mapping implicit state machines, reversing business rules from test output, and more. Every technique is paired with a verification step-because AI output is a draft, never the final word. By the end, you will own a reproducible process for making any undocumented codebase comprehensible, maintainable, and safe to change. Part of The AI Maker Library.

About the author

Ryan Okafor Steele writes for The AI Maker Library.