Reddit MCP Server

Instructions

Implementation Reference

• src/index.ts:576-594 (handler)

  MCP tool handler for 'get_subreddit_info': extracts subreddit parameter, calls the Reddit API service, handles errors, formats the subreddit info using formatSubredditInfo helper, and returns a standardized MCP success response.

  createToolHandler(async (params: z.infer<typeof SimpleSubredditInfoSchema>) => {
      const { subreddit } = params;
      
      const result = await redditAPI.getSubredditInfo(subreddit);
  
      if (!result.success) {
        return createErrorResponse("Error getting subreddit info", result.error);
      }
  
      const data = result.data;
      if (!data || !data.data) {
        return createErrorResponse("Subreddit not found");
      }
  
      const subredditInfo = data.data;
      const formattedInfo = formatSubredditInfo(subredditInfo);
      
      return createSuccessResponse(formattedInfo);
  })

• src/index.ts:565-595 (registration)

  Registration of the 'get_subreddit_info' tool on the MCP server, including name, detailed description, input schema, and handler function.

  server.tool(
    "get_subreddit_info",
    "🏠 Get subreddit information\n" +
    "🎯 What it does: Fetches detailed info about any Reddit subreddit\n" +
    "📝 Required: subreddit name (without r/ prefix)\n" +
    "💡 Examples:\n" +
    "   • Get info: {\"subreddit\": \"programming\"}\n" +
    "   • Check subreddit: {\"subreddit\": \"AskReddit\"}\n" +
    "   • View details: {\"subreddit\": \"MachineLearning\"}\n" +
    "🔍 Output: Subreddit details with description, subscribers, active users, creation date, NSFW status, and URL",
    SimpleSubredditInfoSchema.shape,
    createToolHandler(async (params: z.infer<typeof SimpleSubredditInfoSchema>) => {
        const { subreddit } = params;
        
        const result = await redditAPI.getSubredditInfo(subreddit);
  
        if (!result.success) {
          return createErrorResponse("Error getting subreddit info", result.error);
        }
  
        const data = result.data;
        if (!data || !data.data) {
          return createErrorResponse("Subreddit not found");
        }
  
        const subredditInfo = data.data;
        const formattedInfo = formatSubredditInfo(subredditInfo);
        
        return createSuccessResponse(formattedInfo);
    })
  );

• src/types/index.ts:113-115 (schema)

  Zod input schema for the tool: requires a 'subreddit' string parameter.

  export const SimpleSubredditInfoSchema = z.object({
    subreddit: z.string().describe("Subreddit name to get information about")
  });

• src/services/reddit-api.ts:386-390 (helper)

  Helper method in RedditAPIService that performs the actual API call to fetch subreddit information from Reddit's /r/{subreddit}/about.json endpoint.

  async getSubredditInfo(subreddit: string): Promise<ApiCallResult> {
    return this.makeRequest<{ data: RedditSubreddit }>(
      `/r/${subreddit}/about.json`,
    );
  }

• src/index.ts:161-185 (helper)

  Helper function to format subreddit information into a human-readable string with emojis and details for the MCP response.

  function formatSubredditInfo(subreddit: RedditSubreddit): string {
    const name = subreddit.display_name || 'Unknown';
    const title = subreddit.title || 'No title';
    const description = subreddit.description || 'No description';
    const subscribers = subreddit.subscribers || 0;
    const activeUsers = subreddit.active_user_count || 0;
    const createdDate = subreddit.created_utc ? new Date(subreddit.created_utc * 1000).toLocaleDateString() : 'Unknown';
    const over18 = subreddit.over18 || false;
    
    let result = `🏠 **r/${name}**\n`;
    result += `📝 ${title}\n`;
    result += `📄 Description: ${description}\n`;
    result += `👥 Subscribers: ${subscribers.toLocaleString()}\n`;
    result += `🟢 Active Users: ${activeUsers.toLocaleString()}\n`;
    result += `📅 Created: ${createdDate}\n`;
    result += `🔞 NSFW: ${over18 ? 'Yes' : 'No'}\n`;
    
    if (subreddit.public_description) {
      result += `📋 Public Description: ${subreddit.public_description}\n`;
    }
    
    result += `🔗 URL: https://reddit.com/r/${name}\n`;
    
    return result;
  }