There is one thing worse than a codebase with no documentation: a codebase with documentation that used to be correct.
The README that explains how to set up the development environment, with three commands that no longer exist. The architecture diagram from 2022 that shows services your team has since deleted, alongside two that have been renamed. The API reference whose example payloads have the wrong field names. The onboarding doc whose first link is broken. All of these existed for a reason. All of them, having outlived the world they described, are now lying to anyone who reads them.
Stale documentation is not a small problem. It is worse, in specific and measurable ways, than no documentation at all. And agents make the situation more acute, because agents read documentation eagerly and trust it.
Why this is worse than nothing
A codebase with no documentation produces honest uncertainty. New contributors know they have to learn the system from the code. They ask questions. They read until they understand. The absence is visible and it sets the expectation correctly.
