Enterprise

## When to Use Working in corporate environments where decisions involve legacy systems, formal processes, compliance, multi-team coordination, or architectural trade-offs at scale. ## Quick Reference | Topic | File | |-------|------| | Legacy patterns | `legacy.md` | | Compliance rules | `compliance.md` | | Architecture decisions | `architecture.md` | ## Core Rules ### 1. Legacy First Mindset - Assume existing systems until proven otherwise - Integration cost > development cost in most decisions - "Replace vs wrap" analysis before any architecture change - Document all integration points touched ### 2. Stakeholder Mapping | Role | Cares About | Language | |------|-------------|----------| | Engineering | Technical debt, velocity | Patterns, trade-offs | | Product | Features, timeline | User impact, scope | | Security | Risk, compliance | Threat models, controls | | Finance | Cost, ROI | TCO, licensing | | Legal | Liability, data | Contracts, GDPR | Translate technical decisions into each stakeholder's language. ### 3. Change Management - No breaking changes without migration path - Feature flags before hard switches - Rollback plan for every deployment - Document blast radius of failures ### 4. Compliance Awareness - PCI, SOC2, HIPAA, GDPR implications in every data decision - Audit trail requirements → logging design - Data residency affects architecture - Ask: "Who audits this? What do they need?" ### 5. Documentation as Deliverable Enterprise code without docs = technical debt. - ADRs (Architecture Decision Records) for major choices - Runbooks for operations - API contracts before implementation - Dependency graphs updated with changes ### 6. Security by Default - Principle of least privilege in all designs - Secrets in vault, never in code or config files - Network segmentation assumptions - Zero trust between services ### 7. Observability Investment - Logging, metrics, tracing from day one - Correlation IDs across service boundaries - SLI/SLO definitions before launch - Alert fatigue is a system design failure ## Enterprise Traps - Assuming greenfield when there's always legacy → scope explosion - Optimizing for developer experience over ops burden → 3am pages - Skipping security review for "internal tools" → breach vector - Building before buying → reinventing solved problems - Over-abstracting early → framework nobody understands - Under-documenting decisions → knowledge silos