I stumbled across this tool recently and thought it was worth sharing for anyone managing large codebases or monorepos.

The Problem: We write ADRs (Architectural Decision Records), put them in a folder, and then ignore them. New engineers break architectural rules because they don't know the history.

The Solution: Decision Guardian runs in CI. You define rules (ADRs) linked to file patterns.

What makes it interesting: It goes beyond simple glob matching. You can define rules based on:

Content (Regex): e.g., Alert if someone commits a secret key pattern or a banned function.

Structure (JSONPath): e.g., Watch $.dependencies in package.json to prevent library drift.

Location (Line Range): Protect the first 50 lines of a legacy file.

It’s open source and there's a helper site to generate the rule configs: https://decision-guardian.decispher.com/