Search Trending Topics

Instructions

Implementation Reference

• src/tools/index.ts:203-262 (handler)

  Implements the core logic for the 'search_trending' MCP tool: fetches the top HackerNews stories using hnClient.getTopStories(), retrieves details for the top N posts, filters valid story posts, extracts words from titles (lowercased, non-punctuation, length >= minWordLength, excluding common stopwords and numbers), counts word frequencies, and returns the top 20 trending words with counts and percentage of posts containing them, along with analysis summary.

  async ({ postCount, minWordLength }) => {
    try {
      const topStoryIds = await hnClient.getTopStories();
      const postsToAnalyze = topStoryIds.slice(0, postCount || 50);
      
      const posts = await hnClient.getMultipleItems(postsToAnalyze);
      const validPosts = posts.filter(post => post && post.title && post.type === "story");
  
      // Extract and count words from titles
      const wordCounts = new Map<string, number>();
      const commonWords = new Set(['the', 'and', 'for', 'are', 'but', 'not', 'you', 'all', 'can', 'had', 'her', 'was', 'one', 'our', 'out', 'day', 'get', 'has', 'him', 'his', 'how', 'its', 'may', 'new', 'now', 'old', 'see', 'two', 'way', 'who', 'boy', 'did', 'man', 'end', 'why', 'let', 'put', 'say', 'she', 'too', 'use']);
  
      validPosts.forEach(post => {
        if (post?.title) {
          const words = post.title.toLowerCase()
            .replace(/[^\w\s]/g, ' ')
            .split(/\s+/)
            .filter((word: string) => 
              word.length >= (minWordLength || 4) && 
              !commonWords.has(word) &&
              !/^\d+$/.test(word)
            );
  
          words.forEach((word: string) => {
            wordCounts.set(word, (wordCounts.get(word) || 0) + 1);
          });
        }
      });
  
      // Get top trending words
      const trendingTopics = Array.from(wordCounts.entries())
        .sort((a, b) => b[1] - a[1])
        .slice(0, 20)
        .map(([word, count]) => ({ word, count, percentage: ((count / validPosts.length) * 100).toFixed(1) }));
  
      return {
        content: [{
          type: "text",
          text: JSON.stringify({
            analysis_summary: {
              posts_analyzed: validPosts.length,
              total_unique_words: wordCounts.size,
              min_word_length: minWordLength
            },
            trending_topics: trendingTopics,
            timestamp: new Date().toISOString()
          }, null, 2)
        }]
      };
    } catch (error) {
      logger.error("Failed to get trending topics:", error);
      return {
        content: [{
          type: "text",
          text: `Error analyzing trending topics: ${error instanceof Error ? error.message : String(error)}`
        }],
        isError: true
      };
    }
  }

• src/tools/index.ts:192-263 (registration)

  Registers the 'search_trending' tool via server.registerTool() within the setupTools function, including title 'Search Trending Topics', description, and Zod inputSchema with optional postCount (10-100, default 50) and minWordLength (3-10, default 4) parameters, linking to the inline handler.

  // Search trending topics
  server.registerTool(
    "search_trending",
    {
      title: "Search Trending Topics",
      description: "Find current trending topics and keywords from top HackerNews posts",
      inputSchema: {
        postCount: z.number().min(10).max(100).default(50).optional(),
        minWordLength: z.number().min(3).max(10).default(4).optional()
      }
    },
    async ({ postCount, minWordLength }) => {
      try {
        const topStoryIds = await hnClient.getTopStories();
        const postsToAnalyze = topStoryIds.slice(0, postCount || 50);
        
        const posts = await hnClient.getMultipleItems(postsToAnalyze);
        const validPosts = posts.filter(post => post && post.title && post.type === "story");
  
        // Extract and count words from titles
        const wordCounts = new Map<string, number>();
        const commonWords = new Set(['the', 'and', 'for', 'are', 'but', 'not', 'you', 'all', 'can', 'had', 'her', 'was', 'one', 'our', 'out', 'day', 'get', 'has', 'him', 'his', 'how', 'its', 'may', 'new', 'now', 'old', 'see', 'two', 'way', 'who', 'boy', 'did', 'man', 'end', 'why', 'let', 'put', 'say', 'she', 'too', 'use']);
  
        validPosts.forEach(post => {
          if (post?.title) {
            const words = post.title.toLowerCase()
              .replace(/[^\w\s]/g, ' ')
              .split(/\s+/)
              .filter((word: string) => 
                word.length >= (minWordLength || 4) && 
                !commonWords.has(word) &&
                !/^\d+$/.test(word)
              );
  
            words.forEach((word: string) => {
              wordCounts.set(word, (wordCounts.get(word) || 0) + 1);
            });
          }
        });
  
        // Get top trending words
        const trendingTopics = Array.from(wordCounts.entries())
          .sort((a, b) => b[1] - a[1])
          .slice(0, 20)
          .map(([word, count]) => ({ word, count, percentage: ((count / validPosts.length) * 100).toFixed(1) }));
  
        return {
          content: [{
            type: "text",
            text: JSON.stringify({
              analysis_summary: {
                posts_analyzed: validPosts.length,
                total_unique_words: wordCounts.size,
                min_word_length: minWordLength
              },
              trending_topics: trendingTopics,
              timestamp: new Date().toISOString()
            }, null, 2)
          }]
        };
      } catch (error) {
        logger.error("Failed to get trending topics:", error);
        return {
          content: [{
            type: "text",
            text: `Error analyzing trending topics: ${error instanceof Error ? error.message : String(error)}`
          }],
          isError: true
        };
      }
    }
  );

• src/tools/index.ts:195-201 (schema)

  Input schema definition using Zod for the search_trending tool, specifying postCount: z.number().min(10).max(100).default(50).optional() and minWordLength: z.number().min(3).max(10).default(4).optional().

  {
    title: "Search Trending Topics",
    description: "Find current trending topics and keywords from top HackerNews posts",
    inputSchema: {
      postCount: z.number().min(10).max(100).default(50).optional(),
      minWordLength: z.number().min(3).max(10).default(4).optional()
    }