The Design Patterns MCP Server provides intelligent design pattern recommendations through semantic search and natural language queries, accessing a comprehensive catalog of 555+ patterns across 20+ categories.
Core Capabilities:
Natural language pattern discovery: Find relevant patterns using problem descriptions with confidence-scored recommendations
Advanced search options: Perform keyword, semantic, or hybrid searches with filtering by categories (GoF, Architectural, Microservices, React, AI/ML, Security, etc.) and programming languages
Detailed pattern information: Access comprehensive details including multi-language code examples, relationships, and use cases for any specific pattern
Catalog statistics: Query total pattern counts with optional category breakdowns
High-performance operations: Fast vector search using sqlite-vec with LRU caching and object pooling, delivering 30-40% faster repeated queries
AI assistant integration: Compatible with MCP clients like Claude Code and Cursor for seamless workflow integration
Uses SQLite with vector extensions for efficient semantic search and storage of design pattern embeddings and metadata
Design Patterns MCP Server ๐ฏ
An intelligent MCP (Model Context Protocol) server that provides design pattern recommendations using semantic search and vector embeddings. This project offers access to a comprehensive catalog of 555+ design patterns through a natural language interface.
๐ Overview
The Design Patterns MCP Server is a specialized server that integrates with AI assistants (like Claude, Cursor) to provide intelligent design pattern recommendations. It uses advanced semantic search technologies to find the most appropriate patterns based on natural language problem descriptions.
โจ Key Features
๐ Intelligent Semantic Search: Find patterns using natural problem descriptions
๐ Comprehensive Catalog: 555+ patterns organized in 20+ categories
๐ฏ Contextual Recommendations: Suggestions based on programming language and domain
โก Vector Search: Uses SQLite with vector extensions for efficient search
๐ Multi-language: Support for multiple programming languages
๐ง MCP Integration: Compatible with Claude Code, Cursor and other MCP clients
๐ High Performance: Object Pool pattern prevents memory leaks, 30-40% faster queries
๐พ Smart Caching: LRU cache with 85%+ hit rate
๐๏ธ SOLID Architecture: Clean, maintainable, and testable codebase
๐ Recent Improvements (v0.2.1)
Architecture Refactoring (October 2025)
โ Object Pool Pattern: Eliminates memory leaks with bounded prepared statements
โ Service Layer: Centralized business logic with
PatternService
โ Facade Pattern: Simplified handlers via
PatternHandlerFacade
โ Dependency Injection: Full DI Container integration for testability
โ Performance: 30-40% faster on repeated queries with smart caching
โ Code Quality: 40% reduction in main server file (704โ422 lines)
โ Pattern Catalog: Expanded to 555+ patterns with code examples
๐๏ธ Available Pattern Categories
GoF Patterns: Classic patterns (Creational, Structural, Behavioral)
Architectural Patterns: MVC, MVP, MVVM, Clean Architecture, Hexagonal
Microservices Patterns: Circuit Breaker, Event Sourcing, CQRS, Saga
Cloud Patterns: Auto-scaling, Load Balancing, Service Discovery
AI/ML Patterns: Model Training, RAG, Few-Shot Learning, Continual Learning
React Patterns: Hooks, Server Components, Suspense, React 19 features
Enterprise Patterns: Repository, Unit of Work, Dependency Injection
Security Patterns: Authentication, Authorization, Data Protection
Performance Patterns: Caching, Lazy Loading, Object Pool, Connection Pooling
Concurrency Patterns: Producer-Consumer, Thread Pool, Actor Model
Integration Patterns: Message Queue, Event Bus, API Gateway
Data Access Patterns: Active Record, Data Mapper, Query Object
Testing Patterns: Test Double, Page Object, Builder Pattern for tests
Functional Patterns: Monads, Functors, Higher-Order Functions
Reactive Patterns: Observer, Publisher-Subscriber, Reactive Streams
DDD Patterns: Aggregate, Value Object, Domain Service, Bounded Context
Game Development Patterns: State Machine, Component System, Object Pool
Mobile Patterns: Model-View-Intent, Redux-like patterns, Offline-First
IoT Patterns: Device Twin, Telemetry Ingestion, Edge Processing
Blockchain/Web3 Patterns: DeFi, NFT, DAO, Cross-chain
Anti-Patterns: Practices to avoid and their solutions
๐๏ธ Project Architecture
Refactored Architecture (v0.2.x)
๐ง Main Components
Core Services
DatabaseManager: SQLite operations with Object Pool (prevents memory leaks)
StatementPool: LRU-based pool for prepared statements (max 100)
CacheService: In-memory LRU cache with TTL and metrics
Business Logic
PatternService: Service Layer orchestrating pattern operations
PatternRepository: Data access abstraction (Repository Pattern)
SemanticSearchService: Semantic search with embeddings
PatternMatcher: Pattern matching and ranking logic
Integration
PatternHandlerFacade: Facade simplifying MCP handlers
VectorOperationsService: Vector search using sqlite-vec
LLMBridgeService: Interface for language models (optional)
EmbeddingServiceAdapter: Adapter for embedding services
Infrastructure
SimpleContainer: Dependency Injection container
MigrationManager: Database migrations
PatternSeeder: Initial data seeding
๐ Installation and Setup
Prerequisites
Node.js >= 18.0.0
npm >= 8.0.0 or Bun >= 1.0.0
Installation
MCP Configuration
Add to your MCP configuration file (.mcp.json
or Claude Desktop config):
๐ Usage
Finding Patterns with Natural Language
Use natural language descriptions to find appropriate design patterns through Claude Code:
For object creation problems:
"I need to create complex objects with many optional configurations"
"How can I create different variations of similar objects?"
"What pattern helps with step-by-step object construction?"
For behavioral problems:
"I need to notify multiple components when data changes"
"How to decouple command execution from the invoker?"
"What pattern helps with state-dependent behavior?"
For architectural problems:
"How to structure a microservices communication system?"
"What pattern helps with distributed system resilience?"
"How to implement clean separation between layers?"
For React development:
"How to manage state in React 18/19?"
"What patterns work with React Server Components?"
"How to optimize React performance?"
MCP Tool Functions
find_patterns: Semantic search for patterns using problem descriptions
Returns ranked recommendations with confidence scores
Supports category filtering and programming language preferences
search_patterns: Keyword or semantic search with filtering options
Supports hybrid search (keyword + semantic)
Filter by category, tags, complexity
get_pattern_details: Get comprehensive information about specific patterns
Includes code examples in multiple languages
Shows similar patterns and relationships
Displays implementations and use cases
count_patterns: Statistics about available patterns by category
Optional detailed breakdown by category
๐ ๏ธ Available Commands
๐ฏ Usage Examples
Problem-Based Pattern Discovery
Distributed Systems:
"I need a pattern for handling service failures gracefully" โ Circuit Breaker, Bulkhead
"How to implement eventual consistency in distributed data?" โ Event Sourcing, CQRS
"What pattern helps with service discovery and load balancing?" โ Service Registry, API Gateway
Data Validation:
"I need to validate complex business rules on input data" โ Specification Pattern
"How to compose validation rules dynamically?" โ Chain of Responsibility
"What pattern separates validation logic from business logic?" โ Strategy Pattern
Performance Optimization:
"I need to cache expensive computations efficiently" โ Cache-Aside, Write-Through
"How to implement lazy loading for large datasets?" โ Lazy Loading, Virtual Proxy
"What pattern helps with connection pooling?" โ Object Pool Pattern
Category-Specific Searches
Enterprise Applications:
"Show me enterprise patterns for data access" โ Repository, Unit of Work, Data Mapper
"What patterns help with dependency injection?" โ DI Container, Service Locator
"How to implement domain-driven design?" โ Aggregate, Value Object, Bounded Context
Security Implementation:
"I need authentication and authorization patterns" โ RBAC, OAuth 2.0, JWT
"What patterns help with secure data handling?" โ Encryption at Rest, Defense in Depth
"How to implement role-based access control?" โ RBAC Pattern, Policy-Based Access
๐ง Advanced Configuration
Environment Variables
Using the Refactored Server
Performance Monitoring
๐ Performance and Scalability
Performance Characteristics
Vector Search: Uses sqlite-vec for efficient search in large volumes
Object Pool: Bounded prepared statement cache (max 100) prevents memory leaks
Intelligent Cache: LRU cache with 85%+ hit rate in production
Query Performance: 30-40% faster on repeated queries vs uncached
Optimized Indexes: Specific indexes for different search types
Pagination: Support for large result sets
Metrics: Built-in performance and usage metrics
Benchmarks (from tests)
๐งช Testing
The project includes a comprehensive test suite with 116 passing tests:
Contract Tests: Validate MCP protocol compliance
Integration Tests: Test interaction between components
Performance Tests: Evaluate search and vectorization performance
Unit Tests: Test individual components in isolation
Test Coverage
MCP Protocol: โ 100%
Core Services: โ 95%+
Performance: โ Comprehensive benchmarks
Database: โ Full migration & seeding tests
๐๏ธ Architecture Patterns Used
This project practices what it preaches by implementing:
Pattern | Location | Purpose |
Repository |
| Data access abstraction |
Service Layer |
| Business logic orchestration |
Object Pool |
| Resource management |
Facade |
| Simplified interface |
Dependency Injection |
| Inversion of control |
Strategy |
| Interchangeable algorithms |
Factory |
| Object creation |
Singleton | Via DI Container | Single instance management |
Adapter |
| External service integration |
๐ค Contributing
We welcome contributions! Here's how:
Fork the project
Create a feature branch (
git checkout -b feature/amazing-feature
)Make your changes following our code style
Run tests (
npm test
) and ensure they passRun linting (
npm run lint:fix
)Commit your changes (
git commit -am 'Add amazing feature'
)Push to the branch (
git push origin feature/amazing-feature
)Open a Pull Request
Development Guidelines
Follow SOLID principles
Write tests for new features
Update documentation
Use TypeScript strict mode
Follow existing code patterns
๐ License
This project is licensed under the MIT License. See LICENSE for details.
๐ Useful Links
๐ Support
๐ Issues: Report bugs through GitHub Issues
๐ฌ Discussions: Join GitHub Discussions
๐ง Email: apolosan@protonmail.com
๐ Documentation: Comprehensive architecture and refactoring details available in project documentation
๐ Acknowledgments
Design patterns from the software engineering community
MCP protocol by Anthropic
SQLite and sqlite-vec for efficient storage and search
Open source contributors
Version: 0.2.1
Last Updated: October 2025
Patterns: 555+
Tests: 116 passing
Performance: 30-40% improvement vs v0.1.x
local-only server
The server can only run on the client's local machine because it depends on local resources.
Provides intelligent design pattern recommendations using semantic search through a comprehensive catalog of 200+ patterns across 20 categories. Users can describe programming problems in natural language to discover appropriate design patterns with contextual recommendations.
- ๐ Overview
- ๐๏ธ Project Architecture
- ๐ Installation and Setup
- ๐ Usage
- ๐ ๏ธ Available Commands
- ๐ฏ Usage Examples
- ๐ง Advanced Configuration
- ๐ Performance and Scalability
- ๐งช Testing
- ๐๏ธ Architecture Patterns Used
- ๐ค Contributing
- ๐ License
- ๐ Useful Links
- ๐ Support
- ๐ Acknowledgments