Code Research MCP Server

Instructions

Implementation Reference

• src/index.ts:138-205 (handler)

  The core handler function that performs GitHub searches for repositories and code snippets using the GitHub Search API. Includes caching, language filtering, rate limit handling with token fallback, and formatted output.

  private async searchGitHub(query: string, language?: string, limit: number = 5): Promise<string> {
    const cacheKey = `github:${query}:${language}:${limit}`;
    const cached = cache.get<string>(cacheKey);
    if (cached) return cached;
  
    try {
      // Build search query with language filter if specified
      const q = language ? `${query} language:${language}` : query;
      
      // If GitHub token is invalid, fall back to unauthenticated requests
      const makeRequest = async (endpoint: string, params: any) => {
        try {
          const response = await this.githubInstance.get(endpoint, { params });
          return response;
        } catch (error) {
          if (axios.isAxiosError(error) && error.response?.status === 401) {
            // Retry without auth token
            const response = await this.axiosInstance.get(`https://api.github.com${endpoint}`, {
              params,
              headers: {
                'Accept': 'application/vnd.github.v3+json',
                'User-Agent': 'CodeResearchBot/1.0'
              }
            });
            return response;
          }
          throw error;
        }
      };
  
      const [reposResponse, codeResponse] = await Promise.all([
        makeRequest('/search/repositories', {
          q,
          sort: 'stars',
          order: 'desc',
          per_page: limit
        }),
        makeRequest('/search/code', {
          q,
          sort: 'indexed',
          order: 'desc',
          per_page: limit
        })
      ]);
  
      let result = '=== Top Repositories ===\n';
      result += reposResponse.data.items.map((repo: any, i: number) => 
        `${i + 1}. ${repo.full_name} (⭐ ${repo.stargazers_count})\n` +
        `   ${repo.description || 'No description'}\n` +
        `   ${repo.html_url}\n`
      ).join('\n');
  
      result += '\n=== Relevant Code ===\n';
      result += codeResponse.data.items.map((item: any, i: number) => 
        `${i + 1}. ${item.name} (${item.repository.full_name})\n` +
        `   Path: ${item.path}\n` +
        `   ${item.html_url}\n`
      ).join('\n');
  
      cache.set(cacheKey, result);
      return result;
    } catch (error) {
      throw new McpError(
        ErrorCode.InternalError,
        `GitHub API error: ${error instanceof Error ? error.message : 'Unknown error'}`
      );
    }
  }

• src/index.ts:357-376 (schema)

  Input schema definition for the search_github tool, specifying query (required), optional language filter, and limit.

  inputSchema: {
    type: 'object',
    properties: {
      query: {
        type: 'string',
        description: 'Search query'
      },
      language: {
        type: 'string',
        description: 'Filter by programming language'
      },
      limit: {
        type: 'number',
        description: 'Maximum number of results per category (default: 5)',
        minimum: 1,
        maximum: 10
      }
    },
    required: ['query']
  }

• src/index.ts:354-377 (registration)

  Registration of the search_github tool in the ListToolsRequestSchema handler, including name, description, and input schema.

  {
    name: 'search_github',
    description: 'Search GitHub for repositories and code',
    inputSchema: {
      type: 'object',
      properties: {
        query: {
          type: 'string',
          description: 'Search query'
        },
        language: {
          type: 'string',
          description: 'Filter by programming language'
        },
        limit: {
          type: 'number',
          description: 'Maximum number of results per category (default: 5)',
          minimum: 1,
          maximum: 10
        }
      },
      required: ['query']
    }
  },

• src/index.ts:463-478 (registration)

  Registration of the search_github tool handler in the CallToolRequestSchema switch statement, which extracts arguments and calls the searchGitHub function.

  case 'search_github': {
    const { query, language, limit } = request.params.arguments as { 
      query: string; 
      language?: string;
      limit?: number;
    };
    const results = await this.searchGitHub(query, language, limit);
    return {
      content: [
        {
          type: 'text',
          text: results
        }
      ]
    };
  }