Architecture Skills

The arch-* family handles all structural and systemic design decisions. These skills produce ADRs, component diagrams, and resilience models.

Skills

Skill ID	Description	Model Class
`arch-system`	Full system architecture design: components, boundaries, data flows, and API contracts	`strong`
`arch-reliability`	Analyses failure modes and designs for SLA/SLO targets — redundancy, circuit breakers, retries	`strong`
`arch-scalability`	Models horizontal and vertical scaling strategies, bottleneck identification, caching layers	`cheap`
`arch-security`	Threat modelling (STRIDE), trust boundaries, secret management, zero-trust network design	`strong`

When to Use

Situation	Skill(s)
Designing a new service or module	`arch-system`
Preparing for high-traffic launch	`arch-scalability` + `arch-reliability`
Security review before deployment	`arch-security`
Full architectural review	All four

Instructions That Invoke These Skills

design — primary consumer; full system + security pass
plan — uses arch-system output to estimate complexity and risk
implement — validates implementation against arch-system decisions
review — uses arch-security for security-focused code review

Key Output Formats

arch-system: Component relationship diagram (Mermaid), decision log
arch-reliability: Failure mode table with mitigations
arch-scalability: Load model, recommended infrastructure tier
arch-security: STRIDE threat table, remediation priority

Example

Task: "Design a multi-tenant SaaS backend"

arch-system    → microservices vs modular monolith decision, API gateway pattern
arch-security  → tenant isolation via row-level security + JWT claims audit
arch-reliability → circuit-breaker on third-party integrations, async queue for emails
arch-scalability → PostgreSQL read replicas for reporting, CDN for assets