system-design-router

name	System Design Router
description	Sidecar skill routing templates and architecture patterns for the /sysdesign workflow.
source	user

Skill: System Design Router

Provides structure templates, ADR governance, and default architecture patterns for the /sysdesign workflow.

References

Templates

File	Type	Purpose
references/templates/sysdesign.md	Template	Base structure for system designs (6 domains: Infra, API, DB, Topology, Security, Observability)
references/templates/adr.md	Template	Architecture Decision Record layout (8 sections incl. Validation, Reversibility, Traceability)
references/templates/adr-registry.md	Template	ADR Registry for tracking all decisions with conflict detection
references/templates/sysdesign-report.md	Template	Security & architecture assessment report template for sysdesign

Architecture Patterns

File	Tags	Scale	Purpose
references/architecture-patterns/astro-website.md	website, ssg, ssr, hybrid, seo	small–medium	Astro websites — blogs, docs, marketing, portfolios (SSG/SSR/Hybrid)
references/architecture-patterns/astro-7-fullstack.md	fullstack, hybrid, server-islands, actions	small–large	Astro 7 fullstack app — auth, DB, dashboard, Actions, Server Islands
references/architecture-patterns/cloudflare-workers-d1.md	edge, serverless, sql	small–medium	Serverless Edge with Workers, D1 DB, KV
references/architecture-patterns/nextjs-supabase-postgres.md	fullstack, ssr, realtime	medium–large	Fullstack architecture with Next.js, Supabase, Postgres
references/architecture-patterns/express-mongodb-docker.md	rest-api, nosql, containerized	small–large	Node REST API with Express, MongoDB, Docker
references/architecture-patterns/python-fastapi-postgres.md	rest-api, python, async	medium–enterprise	Async Python API with FastAPI, PostgreSQL, SQLAlchemy
references/architecture-patterns/event-driven-microservices.md	async, pub-sub, saga	large–enterprise	Asynchronous message broker pub-sub / Saga orchestration & choreography
references/architecture-patterns/cqrs-read-write-separation.md	cqrs, read-write, cdc	large–enterprise	Read-write database path separation with CDC sync
references/architecture-patterns/fintech-payment-ledger.md	fintech, ledger, idempotency	medium–enterprise	Double-entry ledger, idempotency dedup, reconciliation
references/architecture-patterns/spatial-geohashing-search.md	geolocation, spatial, postgis	medium–large	Location-based services with Geohashing & PostGIS
references/architecture-patterns/multi-tenant-saas.md	multi-tenant, saas, horizontal	medium–enterprise	Horizontal multi-tenant isolation strategies (stack-agnostic)
references/architecture-patterns/react-native-expo.md	mobile, cross-platform, offline	small–large	Cross-platform mobile with React Native, Expo, SQLite

Auto-Matching Logic

When the /sysdesign create workflow runs Step 2 (Select Architecture Pattern), Agent SHOULD:

1. Read project context: Detect tech stack from project.md (goal, tags), package.json, wrangler.toml, pyproject.toml, or app.json.
2. Match YAML tags: Compare detected stack keywords against each pattern's tags and stack fields in YAML frontmatter.
3. Filter by scale: Use project's scale field (from sysdesign frontmatter) to narrow candidates.
4. Suggest top 1–3 patterns: Present matched patterns to the user with rationale.
5. Horizontal patterns: Always check if multi-tenant-saas.md applies in addition to the primary stack pattern.

Fallback: If no pattern matches, proceed with the base sysdesign.md template without pattern scaffolding.