The concepts that guide my choices.

Code is not the starting point; it is the final consequence of specification. Strict respect for artifact authority: PRD for product intent, Architecture for structure, Specification for contracts, Plan for technical design, Tasks for execution, and Code as the verifiable result. No line is produced without verified contracts.

The Tradeoff: Requires discipline and upfront time before implementation. Skipping this yields short term speed on day one, followed by months of architectural debt and product misalignment.

The language model is only the reasoning engine; the harness is the complete surrounding infrastructure that guides, controls, and makes it reliable. It encompasses durable house rules, safe execution tools, strict permission guardrails, targeted context, persistent memory, and continuous automated verification loops.

The Tradeoff: Keeping the harness calibrated as the system grows requires continuous maintenance of rules and context. Without this infrastructure, even the most capable model hallucinates and violates domain invariants.

Domain logic and use cases completely decoupled from frameworks, HTTP servers, and database drivers. The primary benefit is testability of pure business logic in memory without running external infrastructure, protecting software longevity against obsolescence.

The Tradeoff: More files and indirection per feature. For small CRUD applications it introduces unnecessary complexity, becoming justified when testability and long term maintenance are primary goals.

Deploying distributed caching layers with Upstash Redis, applying cache aside and write through patterns for database relief and ultra low latency. Balanced engineering decisions between strong and eventual consistency with predictable time to live (TTL) expiration policies.

The Tradeoff: Cache invalidation is a classic computing challenge. It requires careful governance to prevent reading stale data and introduces distributed state synchronization into the system.

End to end security with short lived JSON Web Tokens, typed claims for fine grained authorization, and automatic rotation of Refresh Tokens. Mitigating XSS and CSRF vectors through HttpOnly cookies, CORS policies, and BCrypt password hashing.

The Tradeoff: Stateless tokens cannot be revoked instantly without an auxiliary blocklist or credential versioning mechanism, requiring careful balance in token expiration windows.

Whenever a business invariant can be enforced by a database constraint, it must be. Uniqueness, cascade deletion, and state transitions guaranteed by PostgreSQL or Neon cannot be bypassed by buggy code or incorrect automated changes.

The Tradeoff: Less flexibility during rapid migrations and raw database error messages requiring translation layers for user feedback.