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name: Architecture Patterns description: Architecture design templates, mermaid diagrams, documentation patterns, and validation tools. Use when designing system architecture, creating architecture documentation, generating mermaid diagrams, documenting component relationships, designing data flows, planning deployments, creating API architectures, or when user mentions architecture diagrams, system design, mermaid, architecture documentation, or component design. allowed-tools:

Architecture Patterns Skill

CRITICAL: The description field above controls when Claude auto-loads this skill.

Overview

Provides comprehensive architecture design capabilities including mermaid diagram generation, architecture documentation templates, diagram validation, and pattern libraries for common architectural styles (microservices, RAG systems, full-stack applications).

Instructions

Create Architecture Documentation

1. Use bash scripts/create-architecture.sh <project-path> <architecture-type> to scaffold architecture docs
2. Architecture types: nextjs, fastapi, fullstack, microservices, rag, generic
3. Generates complete architecture overview with mermaid diagrams
4. Creates directory structure: docs/architecture/ with overview, components, data-flow, deployment
5. Includes table of contents and cross-references

Validate Mermaid Diagrams

1. Use bash scripts/validate-mermaid.sh <markdown-file> to check mermaid syntax
2. Validates diagram types: graph, flowchart, sequenceDiagram, classDiagram, erDiagram, stateDiagram
3. Checks for syntax errors, invalid node definitions, broken connections
4. Reports line numbers of errors
5. Provides suggestions for common fixes

Generate Diagram Placeholders

1. Use bash scripts/generate-diagrams.sh <output-dir> <diagram-types> to create diagram templates
2. Diagram types: component, data-flow, deployment, api, security, all
3. Creates markdown files with properly formatted mermaid code blocks
4. Includes comments explaining diagram sections
5. Provides example nodes and relationships

Update Existing Architecture

1. Use bash scripts/update-architecture.sh <architecture-file> <section> to add new sections
2. Sections: component, api, security, deployment, data-flow
3. Inserts section with proper heading hierarchy
4. Adds mermaid diagram placeholder
5. Preserves existing content and formatting

Export Diagrams to Files

1. Use bash scripts/export-diagrams.sh <markdown-file> <output-dir> to extract diagrams
2. Extracts all mermaid code blocks from documentation
3. Creates individual .mmd files for each diagram
4. Names files based on diagram titles or section headings
5. Generates index.md listing all exported diagrams

Available Scripts

• create-architecture.sh: Scaffold complete architecture documentation with diagrams
• validate-mermaid.sh: Validate mermaid diagram syntax and structure
• generate-diagrams.sh: Create diagram template placeholders
• update-architecture.sh: Add new sections to existing architecture docs
• export-diagrams.sh: Extract mermaid diagrams to separate files

Templates

• architecture-overview.md: Master architecture document template with TOC
• component-diagram.md: Component architecture with relationships
• data-flow-diagram.md: Data flow and processing pipelines
• deployment-diagram.md: Infrastructure and deployment architecture
• api-architecture.md: API design, endpoints, and authentication
• security-architecture.md: Security patterns, auth flows, data protection

Examples

See examples/ directory for detailed usage examples:

• example-nextjs-architecture.md - Next.js 15 App Router architecture
• example-fastapi-architecture.md - FastAPI backend with PostgreSQL
• example-fullstack-architecture.md - Full stack Next.js + FastAPI
• example-ai-rag-architecture.md - RAG system with vector database
• example-microservices-architecture.md - Microservices pattern with API gateway

Architecture Patterns

Component Architecture Pattern

• Define system components and boundaries
• Show component relationships and dependencies
• Identify shared services and libraries
• Document component responsibilities

Data Flow Pattern

• Map data movement through system
• Show transformation and processing stages
• Identify data sources and destinations
• Document data formats and protocols

Deployment Pattern

• Define infrastructure components
• Show service deployment topology
• Identify scaling and redundancy strategies
• Document environment configurations

API Architecture Pattern

• Design API structure and endpoints
• Define authentication and authorization
• Show request/response flows
• Document rate limiting and caching

Security Architecture Pattern

• Define security layers and boundaries
• Show authentication and authorization flows
• Identify threat vectors and mitigations
• Document encryption and data protection

Mermaid Diagram Types

Graph/Flowchart Diagrams

graph TD
    A[Start] --> B{Decision}
    B -->|Yes| C[Action 1]
    B -->|No| D[Action 2]

Sequence Diagrams

sequenceDiagram
    Client->>API: Request
    API->>Database: Query
    Database-->>API: Result
    API-->>Client: Response

Class Diagrams

classDiagram
    class User {
        +String name
        +login()
    }

Entity Relationship Diagrams

erDiagram
    USER ||--o{ ORDER : places
    ORDER ||--|{ ITEM : contains

State Diagrams

stateDiagram-v2
    [*] --> Idle
    Idle --> Processing
    Processing --> Complete

Output Standards

• Use mermaid for all diagrams (ensures renderability)
• Include diagram titles and descriptions
• Add comments explaining key components
• Follow consistent naming conventions
• Use proper markdown heading hierarchy
• Include cross-references between documents

Validation Checks

Scripts perform these validations:

• Mermaid syntax correctness
• Node and edge definitions
• Diagram type compatibility
• Character escaping in labels
• Proper code block formatting
• Complete relationship definitions

Integration

This skill is used by:

• planning:architecture command - Generate architecture docs
• architecture-designer agent - Create system designs
• Documentation tools - Include architecture diagrams
• Code generation - Architecture-aware scaffolding

Best Practices

1. Start with high-level overview diagram
2. Create separate diagrams for each architectural concern
3. Use consistent component naming across diagrams
4. Include legends for symbols and colors
5. Keep diagrams focused and readable (max 15-20 nodes)
6. Document assumptions and constraints
7. Version architecture documents
8. Update diagrams when system changes

Common Diagram Patterns

Layered Architecture

graph TB
    UI[Presentation Layer]
    BL[Business Logic Layer]
    DA[Data Access Layer]
    DB[(Database)]
    UI --> BL
    BL --> DA
    DA --> DB

Event-Driven Architecture

graph LR
    P[Producer] -->|Event| Q[Event Queue]
    Q -->|Event| C1[Consumer 1]
    Q -->|Event| C2[Consumer 2]

Microservices Architecture

graph TB
    AG[API Gateway]
    AG --> MS1[Service 1]
    AG --> MS2[Service 2]
    AG --> MS3[Service 3]
    MS1 --> DB1[(DB 1)]
    MS2 --> DB2[(DB 2)]

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Purpose: Comprehensive architecture design and documentation Used by: Architecture designers, system planners, documentation tools