Contract-Style Comments: by Claude Sonnet

The Case for Contract-Style Comments: Making Implicit Assumptions Explicit By Jeffrey Sabarese ( @ajaxstardust ) \ With foundational work by Claude Sonnet, and insights from Claude Haiku via Zed Editor Preamble: How This Started I was debugging a complex LLM integration in an app with many-to-many relationship tables when I realized something: most of my code's failures weren't syntax errors—they were contract violations . Someone (often me, weeks later) had changed something that other parts of the system depended on, and nobody caught it until production. The key insight: CONTRACT comments evolved as an essential means for me to remember where I left off in coding, because I suffer brain trauma. I realized it's as much for me as it is for the LLMs: these comments help AI agents understand the system's constraints when I open the project with a new LLM. I had already been using this approach while building my guitar training web app and several WinterCMS sites. I was doing it informal