One-way door check

Some decisions are easy to reverse — you can change a UI component, rename a variable, or swap a utility function with no lasting consequences. These are two-way doors: walk through, and if it's wrong, walk back.

Other decisions create gravity. Once traffic, users, or other code depends on them, changing course gets expensive. A database schema migration after launch. An API contract that external consumers rely on. An auth boundary that shapes your entire permission model. These are one-way doors.

The most expensive mistakes in software aren't bugs. They're irreversible architectural decisions made too quickly.

What gets flagged

Data models and database schemas

Files matching: schema.prisma, schema.graphql, *.sql, migration*, models.py, models.ts, entities.py, entities.ts

Data models are the hardest decisions to reverse. Once your database has rows, every schema change requires a migration. Column renames break queries. Relationship changes cascade through your entire application.