Prompt Contracts v2: Add Validation Rules to Your AI Prompts (Template Included)

My most-read post on this blog is about prompt contracts — treating prompts like API specs with defined inputs, outputs, and error handling. But the original had a gap: it told you what to specify, not how to validate that the AI followed the spec. This is the v2. It adds validation rules you can check automatically. Quick Recap: What's a Prompt Contract? A prompt contract is a structured prompt with three sections: INPUT: what you're giving the AI OUTPUT: what you expect back (format, structure, length) ERROR: what to do when something doesn't match If you haven't read the original, the core idea is: ambiguous prompts produce ambiguous outputs. Specs produce specs. The Problem With v1 Prompt contracts work. But they rely on you manually checking whether the output matches. That's fine for one-off tasks. It breaks down when you're running prompts in scripts, pipelines, or daily workflows. You need machine-checkable rules. Validation Rules: The v2 Addition Add a VALIDATION\ block to you