dautroc/better-rspec-mcp
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The Better RSpec MCP Server is a Model Context Protocol server that provides comprehensive RSpec guidance, examples, and best practices based on Better Specs guidelines.
Better RSpec MCP Server
A Model Context Protocol (MCP) server that provides comprehensive RSpec guidance, examples, and best practices based on Better Specs guidelines.
Overview
This MCP server enables AI assistants to access structured RSpec knowledge and provide intelligent testing guidance. It includes tools for generating examples, validating code, getting configuration help, and accessing comprehensive Better Specs guidelines.
Features
🛠️ Tools
get_rspec_guidance- Get Better Specs guidance for specific topicssearch_rspec_guidelines- Search through Better Specs guidelines using keywordsget_category_overview- Get an overview of all guidelines in a specific categorygenerate_spec_example- Generate RSpec examples following best practicesvalidate_spec_code- Validate RSpec code against Better Specs guidelinesget_rspec_configuration- Get configuration templates and setup guidance
📚 Resources
- Better Specs Guidelines - Complete collection of guidelines by category
- Code Examples Library - Comprehensive examples for different spec types
- Anti-patterns Database - Common mistakes and how to avoid them
- Configuration Templates - Ready-to-use RSpec configurations
- Cheatsheet - Quick reference for Better Specs principles
💬 Prompts
- Code Review - Comprehensive RSpec code review templates
- Test Planning - Templates for planning comprehensive test coverage
- Refactoring - Guidance for improving existing test suites
- Project Setup - Complete setup guides for new RSpec projects
Installation
Prerequisites
- Node.js 18+
Quick Setup (Recommended)
Using npx (no installation required):
Add to your MCP client configuration (e.g., Claude Desktop):
{
"mcpServers": {
"better-rspec": {
"command": "npx",
"args": ["--yes", "better-rspec-mcp@latest"]
}
}
}
Alternative: Local Development Setup
- Clone and install dependencies:
git clone <repository-url>
cd better-rspec-mcp
npm install
- Build the project:
npm run build
- Configure MCP client:
{
"mcpServers": {
"better-rspec": {
"command": "node",
"args": ["/path/to/better-rspec-mcp/dist/index.js"]
}
}
}
Development
Project Structure
src/
├── index.ts # Entry point
├── server.ts # Main MCP server
├── types/ # TypeScript type definitions
├── tools/ # MCP tools implementation
│ ├── guidance.ts # RSpec guidance tools
│ ├── examples.ts # Example generation
│ ├── validation.ts # Code validation
│ └── configuration.ts # Configuration help
├── resources/ # MCP resources
├── prompts/ # MCP prompts
├── knowledge/ # Knowledge base system
└── utils/ # Utility functions
data/
├── guidelines/ # Better Specs guidelines (Markdown)
├── examples.json # Code examples database
├── antipatterns.json # Anti-patterns database
└── configurations.json # Configuration templates
Development Commands
# Development with hot reload
npm run dev
# Build for production
npm run build
# Run tests
npm test
# Lint code
npm run lint
# Type checking
npm run type-check
Adding New Guidelines
- Create a new Markdown file in
data/guidelines/:
---
title: "Your Guideline Title"
category: "naming|organization|expectations|data-setup|mocking|shared-examples|performance|configuration"
tags: ["tag1", "tag2"]
priority: "high|medium|low"
relatedGuidelines: ["other-guideline-ids"]
---
# Your guideline content here
- The knowledge base will automatically load it on server restart.
Adding New Examples
Add entries to data/examples.json:
{
"id": "unique-example-id",
"title": "Example Title",
"description": "What this example demonstrates",
"specType": "model|request|system|service|job|controller|helper",
"scenario": "What you're testing",
"badCode": "Example of what not to do (optional)",
"goodCode": "Example of the right way",
"explanation": "Why this is better",
"tags": ["relevant", "tags"],
"complexity": "beginner|intermediate|advanced"
}
Better Specs Principles
This MCP server is built around the core Better Specs principles:
- Describe methods clearly - Use
.methodfor class methods,#methodfor instance methods - Use contexts - Start with "when", "with", or "without"
- Keep descriptions short - Under 40 characters, use contexts for longer scenarios
- One expectation per test - In unit tests (exceptions for integration tests)
- Test all cases - Happy path, edge cases, and failures
- Use expect syntax - Modern
expect().toinstead of deprecatedshould - Use subject appropriately - For the main object under test
- Use let/let! - Instead of instance variables for test data
- Mock sparingly - Prefer real behavior, mock external boundaries only
- Test what you see - Focus on integration tests over controller unit tests
API Reference
Tools
get_rspec_guidance
Get Better Specs guidance for specific topics.
Parameters:
topic(string, required) - RSpec topic to get guidance oncategory(string, optional) - Specific category to focus onincludeExamples(boolean, default: true) - Whether to include examplescomplexity(string, optional) - Complexity level filter
generate_spec_example
Generate RSpec example code following Better Specs guidelines.
Parameters:
specType(string, required) - Type of spec (model, request, system, etc.)scenario(string, required) - What you want to testincludeSetup(boolean, default: true) - Include setup codestyle(string, default: "comprehensive") - Example stylecomplexity(string, default: "intermediate") - Complexity level
validate_spec_code
Validate RSpec code against Better Specs guidelines.
Parameters:
code(string, required) - RSpec code to validatecheckAll(boolean, default: true) - Run all validation checksspecificChecks(array, optional) - Specific rules to checkreturnSuggestions(boolean, default: true) - Include suggestions
get_rspec_configuration
Get RSpec configuration templates and setup guidance.
Parameters:
type(string, required) - Configuration type (spec_helper, rails_helper, etc.)projectType(string, default: "rails") - Project typeincludeComments(boolean, default: true) - Include explanatory commentsfeatures(array, optional) - Additional features to include
Resources
better-specs://guidelines- All guidelinesbetter-specs://examples- All examplesbetter-specs://antipatterns- All anti-patternsbetter-specs://configurations- All configuration templatesbetter-specs://cheatsheet- Quick reference guide
Prompts
review_rspec_code- Comprehensive code reviewplan_comprehensive_tests- Test planning guidancerefactor_test_suite- Refactoring recommendationssetup_rspec_project- Project setup guidance
Contributing
- Fork the repository
- Create a feature branch
- Make your changes
- Add tests if applicable
- Run linting and tests
- Submit a pull request
Acknowledgments
- Better Specs - The original source of RSpec best practices
- RSpec - The testing framework this server supports
- Model Context Protocol - The protocol this server implements