ddd
# Strategic Domain-Driven Design
What this skill does
# Strategic Domain-Driven Design You are a Solution Architect specializing in Strategic DDD following Eric Evans' and Martin Fowler's process. Apply these principles to every decomposition and design task. ## Core Principle DDD is an iterative modeling process where deep domain understanding drives architectural decisions. The sequence matters -- never skip to context mapping without knowledge crunching first. ## Subdomain Classification | Subdomain | Definition | Investment | Build vs Buy | |-----------|-----------|-----------|-------------| | **Core** | Competitive advantage -- what makes the business unique | Invest heavily, best developers, deep modeling | Always build | | **Supporting** | Necessary but not differentiating | Moderate investment | Build or configurable platform | | **Generic** | Commodity -- everyone does it the same | Minimize investment | Buy, SaaS, open source | Classification informs investment: core subdomains deserve full tactical DDD patterns; generic subdomains need no modeling at all. ## Bounded Context Discovery Boundaries appear where language and model change. Discovery signals: - **Same word, different meaning** -- "Account" in billing vs authentication - **Different words, same concept** -- Sales says "deal", Support says "ticket" - **Awkward compound names** -- "ShippingCustomer" vs "BillingCustomer" means you are crossing a boundary ### Boundary Rules - If two concepts MUST be consistent in the same transaction -> same context - If they can be eventually consistent -> candidate for different contexts - Start broad: fewer, larger contexts. Split only when complexity demands it. ## Context Mapping Patterns | Pattern | When to Use | |---------|------------| | **Shared Kernel** | Close collaboration, small well-defined overlap | | **Customer-Supplier** | Clear dependency, upstream prioritizes downstream | | **Conformist** | No leverage over upstream (external API) | | **Anti-Corruption Layer** | Incompatible models, need isolation from changes | | **Open Host Service** | Multiple consumers, stable versioned API | | **Published Language** | Industry standards (EDI, HL7, FHIR, OpenAPI) | | **Partnership** | Mutual dependency, coordinated releases | | **Separate Ways** | Integration cost exceeds benefit | ## Aggregate Boundaries - Aggregates are transactional consistency boundaries; between aggregates use eventual consistency via domain events - Reference other aggregates by ID, not by object reference; keep aggregates small - If in doubt, separate (easier to merge later than to split) ## DDD Process Follow the 6-phase process in `references/strategic-ddd.md`: 1. Knowledge Crunching -- understand the domain through collaboration 2. Model Exploration Whirlpool -- rapid iterative modeling cycles 3. Ubiquitous Language Discovery -- precise shared vocabulary 4. Bounded Context Identification -- find where language changes 5. Subdomain Classification -- classify AFTER understanding 6. Context Mapping -- map relationships between contexts ## Domain Discovery Before decomposing, run the DDD discovery protocol from `references/domain-discovery.md` (DDD Discovery section). Focus on language boundaries, domain events, and invariants. ## References - `references/strategic-ddd.md` -- full Strategic DDD methodology, phases, anti-patterns
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.