---
title: "Comment by Oliver Zehentleitner on \"Don't Repeat Yourself: the second copy is the bug\" | Hashnode"
description: "This gets even more interesting with coding agents. A second copy is no longer just maintenance debt. It can become a second source of truth that an agent confi"
url: "https://hashnode.com/posts/don-t-repeat-yourself-the-second-copy-is-the-bug/6abb71d1a5ec1a600edd48cc/comment/6acb6e082b85c3fa4453f15c"
---

[Discussion](https://hashnode.com/posts/don-t-repeat-yourself-the-second-copy-is-the-bug/6abb71d1a5ec1a600edd48cc)

Comment [Don't Repeat Yourself: the second copy is the bug](https://hashnode.com/posts/don-t-repeat-yourself-the-second-copy-is-the-bug/6abb71d1a5ec1a600edd48cc)

[Oliver Zehentleitner](https://hashnode.com/@oliver-zehentleitner)

[Oct 11](https://hashnode.com/posts/don-t-repeat-yourself-the-second-copy-is-the-bug/6abb71d1a5ec1a600edd48cc/comment/6acb6e082b85c3fa4453f15c)

This gets even more interesting with coding agents.

A second copy is no longer just maintenance debt. It can become a second source of truth that an agent confidently follows after the original has changed.

I've seen the same rule copied into CLAUDE.md, AGENTS.md, tool-specific config and project docs. Keeping those synchronized is already hard for humans; agents just make the stale copy actionable.

So I increasingly think DRY applies to knowledge and instructions at least as much as it does to code: one canonical source, references everywhere else.