So you've decided pre-execution gates belong in your architecture. Good choice. Now you need to actually build one. The question isn't whether you need a gate, it's what shape should it take in your codebase.

There are three main patterns engineers use, and each has a different profile of complexity, flexibility, and maintainability. The right one depends on how dynamic your rules are and how much they're likely to change.

Pattern 1: Decision Table (Simple, Explicit, Limited)

This is the pattern to start with. Your rules are explicit in code, organized in a table structure, and evaluated deterministically.

The idea: define your rules as data, then write an evaluator that walks through them in order.

# Rules are data, not scattered logic AUTHORIZATION_RULES = [ { " condition " : lambda action , user : ( action [ " operation " ] == " delete_data " and user .…