fifteen-factor-app
Cloud-native SaaS architecture methodology extending Twelve-Factor with three additional factors (API First, Telemetry, Security). Use when planning SaaS tools, product software architecture, microservices design, PRPs/PRDs, or cloud-native application development; when the user says "fifteen factor", "12 factor", "SaaS architecture", "cloud-native design", "application architecture", "microservices best practices"; or when in a planning/architecture session. Do NOT use for greenfield monolith design without cloud-native constraints, internal tooling that will never ship as a service, or local-only scripts.
What this skill does
# Fifteen-Factor App Methodology ## Overview The Fifteen-Factor App methodology extends the original Twelve-Factor App principles (created by Heroku in 2012) with three additional factors essential for modern cloud-native applications: API First, Telemetry, and Security. This methodology provides architectural principles and guidelines for building software-as-a-service applications that are: - **Performant** - Optimised for speed and efficiency - **Scalable** - Designed for horizontal scaling without significant changes - **Manageable** - Easy to deploy, monitor, and maintain - **Resilient** - Robust against failures with graceful degradation ## When to Apply This Methodology Apply the Fifteen-Factor principles during: 1. **Architecture Planning** - When designing new applications or microservices 2. **PRP/PRD Creation** - When documenting technical requirements and specifications 3. **Code Reviews** - When evaluating whether implementations follow best practices 4. **Migration Planning** - When modernising legacy applications for cloud deployment 5. **Technical Debt Assessment** - When identifying architectural improvements ## The Fifteen Factors at a Glance | Factor | Principle | Key Concept | |--------|-----------|-------------| | I. Codebase | One codebase, many deploys | Single repo per app, version controlled | | II. Dependencies | Explicitly declare and isolate | No implicit system-wide packages | | III. Config | Store in environment | Never hardcode configuration | | IV. Backing Services | Treat as attached resources | Databases, caches are swappable resources | | V. Build, Release, Run | Strict separation | Immutable releases, no runtime changes | | VI. Processes | Stateless and share-nothing | Horizontal scaling, no sticky sessions | | VII. Port Binding | Export via port | Self-contained, no runtime injection | | VIII. Concurrency | Scale out via process model | Horizontal over vertical scaling | | IX. Disposability | Fast startup, graceful shutdown | Maximise robustness | | X. Dev/Prod Parity | Keep environments similar | Continuous deployment | | XI. Logs | Treat as event streams | Separate generation from processing | | XII. Admin Processes | Run as one-off processes | Same environment as app | | **XIII. API First** | Design contracts first | Enable parallel development | | **XIV. Telemetry** | Monitor everything | APM, health checks, domain metrics | | **XV. Security** | Authentication & Authorisation | RBAC, identity per request | ## Architecture Checklist When creating a PRP, PRD, or architecture plan, evaluate the design against each factor. Use this checklist for quick validation: ``` □ Single codebase in version control □ All dependencies explicitly declared □ Configuration externalised to environment □ Backing services abstracted and swappable □ Build, release, run stages separated □ Stateless processes (no sticky sessions) □ Services self-contained with port binding □ Designed for horizontal scaling □ Fast startup and graceful shutdown □ Dev/staging/prod environments aligned □ Logs streamed to external aggregator □ Admin tasks automated and reproducible □ API contracts defined before implementation □ Telemetry: APM, health checks, metrics □ Security: Authentication and authorisation ``` ## Resources Detailed documentation for each factor is available in the references directory: - `references/overview.md` - Complete factor summary with diagrams - `references/original-factors.md` - Factors I-XII with implementation examples - `references/modern-extensions.md` - Factors XIII-XV (API First, Telemetry, Security) - `references/setup-and-tools.md` - Tooling recommendations and quick start Read the appropriate reference file for detailed guidance on specific factors.
Related in Design
contribute
IncludedLocal-only OSS contribution command center. Auto-refreshes the user's in-flight PR and issue state on invoke so conversations start with full context — no need to brief Claude on what's in flight. Helps the user find issues to contribute to on GitHub, builds per-repo dossiers of what each upstream expects (CLA, DCO, branch convention, AI policy, draft-first, review bots, issue templates), runs deterministic gates before any external action so AI-assisted contributions don't reach maintainers as slop. State is markdown-only: candidate files at ~/.contribute-system/candidates/, repo dossiers at ~/.contribute-system/research/, append-only event log at ~/.contribute-system/log.jsonl. No database, no cloud calls. Use when the user asks about their PRs / issues / contributions, wants to find new work to take on, claim an issue, build/refresh a repo's dossier, or draft a Design Issue or PR. Trigger with "/contribute", "what's my PR status", "find a contribution", "claim issue X", "draft a Design Issue for Y", "refresh dossier for Z".
architectural-analysis
IncludedUser-triggered deep architectural analysis of a codebase or scoped subtree across eight modes — information architecture, data flow, integration points, UI surfaces, interaction patterns, data model, control flow, and failure modes. This skill should be used when the user asks to "diagram this codebase," "map the architecture," "show the data flow," "give me an ERD," "trace control flow," "find the integration points," "verify the layout pattern," "audit the UX architecture," or any similar request whose primary deliverable is mermaid diagrams plus cited reports under docs/architecture/. Dispatches haiku/sonnet sub-agents in parallel for per-mode exploration, then verifies every citation mechanically before any node lands in a diagram. Not for one-off prose explanations of code (use code-explanation) or for high-level system design from scratch (use system-design).
mcp
IncludedModel Context Protocol (MCP) server development and tool management. Languages: Python, TypeScript. Capabilities: build MCP servers, integrate external APIs, discover/execute MCP tools, manage multi-server configs, design agent-centric tools. Actions: create, build, integrate, discover, execute, configure MCP servers/tools. Keywords: MCP, Model Context Protocol, MCP server, MCP tool, stdio transport, SSE transport, tool discovery, resource provider, prompt template, external API integration, Gemini CLI MCP, Claude MCP, agent tools, tool execution, server config. Use when: building MCP servers, integrating external APIs as MCP tools, discovering available MCP tools, executing MCP capabilities, configuring multi-server setups, designing tools for AI agents.
react-native-skia
IncludedDesign, build, debug, and optimise high-polish animated graphics in React Native or Expo using @shopify/react-native-skia, Reanimated, and Gesture Handler. Use when the user wants canvas-driven UI, shaders, paths, rich text, image filters, sprite fields, Skottie, video frames, snapshots, web CanvasKit setup, or performance tuning for custom motion-heavy elements such as loaders, hero art, cards, charts, progress indicators, particle systems, or gesture-driven surfaces. Also use when the user asks for fluid, glow, glass, blob, parallax, 60fps/120fps, or GPU-friendly animated effects in React Native, even if they do not explicitly say "Skia". Do not use for ordinary form/layout work with standard views.
plaid
IncludedProduct Led AI Development — guides founders from idea to launched product. Six capabilities: Idea (discover a product idea), Validate (pressure-test the idea against fatal flaws, problem reality, competition, and 2-week MVP feasibility), Plan (vision intake + document generation), Design (translate image references into a design.md spec), Launch (go-to-market strategy), and Build (roadmap execution). Use when someone says "PLAID", "plaid idea", "help me find an idea", "product idea", "idea from my business", "idea from my expertise", "plaid validate", "validate my idea", "pressure-test", "is this idea good", "find fatal flaws", "validate the problem", "plan a product", "define my vision", "generate a PRD", "product strategy", "plaid design", "design from image", "translate image to design", "create design.md", "extract design tokens", "plaid launch", "go-to-market", "launch plan", "GTM strategy", "launch playbook", "plaid build", "build the app", "start building", or "execute the roadmap".
nextjs-framer-motion-animations
IncludedAdds production-safe Motion for React or Framer Motion animations to Next.js apps, including reveal, hover and tap micro-interactions, whileInView, stagger, AnimatePresence, layout and layoutId transitions, reorder, scroll-linked UI, and lightweight route-content transitions. Use when the user asks to add, refactor, or debug Motion or Framer Motion in App Router or Pages Router codebases, especially around server/client boundaries, reduced motion, LazyMotion, bundle size, hydration, or route transitions. Avoid for GSAP-style timelines, WebGL or 3D scenes, heavy scroll storytelling, or CSS-only effects unless Motion is explicitly requested.