# Pre-Execution Gates: How to Block Before You Execute (Part 2/3)

This is Part 2 of a three-part series on AI governance architecture. In Part 1, we explored why signed receipts can't solve the negative proof problem—the challenge of proving that unauthorized actions didn't happen. Today, we'll examine the architectural pattern that does solve it: pre-execution gates that evaluate governance policy before any AI execution occurs. Note: This series explores architectural patterns for AI governance based on regulatory requirements and cryptographic best practice