one-way-door

# 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. **Questions to ask:** - Have you mapped all the relationships between entities? - Will this schema support the queries you need without N+1 problems? - Are you normalizing appropriately for your read/write patterns? ### Infrastructure and deployment configs Files matching: `docker-compose*`, `Dockerfile`, `*.tf`, `terraform*`, `pulumi*`, `cdk*`, `cloudformation*`, `k8s*`, `kubernetes*`, `helm*` Infrastructure choices constrain everything...