github-pr-review-mcp copilot-instructions.md

GitHub Copilot Instructions for GitHub PR Review MCP

Project Context

This is a Model Context Protocol (MCP) server that provides GitHub PR review capabilities to AI clients. Built with TypeScript, FastMCP, and GitHub API.

Architecture

Core Files

• src/index.ts - Register MCP tools here
• src/github-service.ts - All GitHub API calls go through this service
• src/code-analyzer.ts - Static code analysis (pure functions)
• src/types.ts - Zod schemas and TypeScript types
• src/review-prompt.ts - Review prompt generation

Adding New Tools (3 Steps)

1. Define Zod schema in types.ts
2. Add service method in github-service.ts using this.octokit
3. Register tool in index.ts with server.addTool()

Code Standards

• TypeScript: Strict mode, ES2022 modules
• Strong typing: Always use explicit, strong types. Use Zod schemas for runtime validation, define explicit interface or type for TypeScript
• Use ? for optional: Don't use | null | undefined, use optional properties (?) instead
• Style: 2 spaces, double quotes, semicolons required, 80 char max line
• Naming: kebab-case files, PascalCase classes, camelCase functions
• Imports: External → internal, sorted alphabetically, use .js extension

Critical Rules

DO:

• Use GitHubService for all GitHub API calls
• Define Zod schemas in types.ts for all parameters
• Run npm run validate before committing
• Handle errors with try-catch, log with console.error
• Update README.md when adding tools

DON'T:

• Edit dist/ files (generated)
• Use any unnecessarily
• Bypass service layer
• Skip validation
• Break existing functionality

Error Handling

Always wrap GitHub API calls in try-catch:

try {
  const result = await this.octokit.pulls.get({...});
  return result.data;
} catch (error) {
  const message = error instanceof Error ? error.message : String(error);
  console.error("Error fetching PR:", message);
  throw new Error(`Failed to fetch PR: ${message}`);
}