Search HackerNews Posts

Instructions

Implementation Reference

• src/index.ts:46-61 (handler)

  The handler function for the 'search-posts' tool. It constructs query parameters from inputs, calls the HackerNews Algolia /search endpoint via the fetchHN helper, and returns the results as both text and structured content.

  async ({ query, tags, numericFilters, page, hitsPerPage }) => {
    const params = new URLSearchParams();
    if (query) params.append('query', query);
    if (tags) params.append('tags', tags);
    if (numericFilters) params.append('numericFilters', numericFilters);
    if (page !== undefined) params.append('page', page.toString());
    if (hitsPerPage !== undefined) params.append('hitsPerPage', hitsPerPage.toString());
    
    const endpoint = `/search?${params.toString()}`;
    const result = await fetchHN(endpoint);
    
    return {
      content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
      structuredContent: result
    };
  }

• src/index.ts:28-45 (schema)

  The inputSchema and outputSchema definitions using Zod for validating parameters and response of the 'search-posts' tool.

  {
    title: 'Search HackerNews Posts',
    description: 'Search HackerNews posts by relevance (sorted by relevance, then points, then number of comments)',
    inputSchema: {
      query: z.string().describe('Search query text'),
      tags: z.string().optional().describe('Filter tags (e.g., "story", "comment", "poll", "show_hn", "ask_hn", "front_page", "author_USERNAME", "story_ID")'),
      numericFilters: z.string().optional().describe('Numeric filters (e.g., "points>100", "created_at_i>1672531200")'),
      page: z.number().optional().describe('Page number for pagination (default: 0)'),
      hitsPerPage: z.number().optional().describe('Number of results per page (default: 20)')
    },
    outputSchema: {
      hits: z.array(z.any()),
      nbHits: z.number(),
      nbPages: z.number(),
      page: z.number(),
      hitsPerPage: z.number()
    }
  },

• src/index.ts:26-62 (registration)

  The complete registration of the 'search-posts' tool using McpServer.registerTool, including name, schema, and handler.

  server.registerTool(
    'search-posts',
    {
      title: 'Search HackerNews Posts',
      description: 'Search HackerNews posts by relevance (sorted by relevance, then points, then number of comments)',
      inputSchema: {
        query: z.string().describe('Search query text'),
        tags: z.string().optional().describe('Filter tags (e.g., "story", "comment", "poll", "show_hn", "ask_hn", "front_page", "author_USERNAME", "story_ID")'),
        numericFilters: z.string().optional().describe('Numeric filters (e.g., "points>100", "created_at_i>1672531200")'),
        page: z.number().optional().describe('Page number for pagination (default: 0)'),
        hitsPerPage: z.number().optional().describe('Number of results per page (default: 20)')
      },
      outputSchema: {
        hits: z.array(z.any()),
        nbHits: z.number(),
        nbPages: z.number(),
        page: z.number(),
        hitsPerPage: z.number()
      }
    },
    async ({ query, tags, numericFilters, page, hitsPerPage }) => {
      const params = new URLSearchParams();
      if (query) params.append('query', query);
      if (tags) params.append('tags', tags);
      if (numericFilters) params.append('numericFilters', numericFilters);
      if (page !== undefined) params.append('page', page.toString());
      if (hitsPerPage !== undefined) params.append('hitsPerPage', hitsPerPage.toString());
      
      const endpoint = `/search?${params.toString()}`;
      const result = await fetchHN(endpoint);
      
      return {
        content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
        structuredContent: result
      };
    }
  );

• src/index.ts:11-17 (helper)

  Shared helper function fetchHN used by the 'search-posts' handler (and other tools) to make API calls to the HackerNews Algolia API.

  async function fetchHN(endpoint: string): Promise<any> {
    const response = await fetch(`${HN_API_BASE}${endpoint}`);
    if (!response.ok) {
      throw new Error(`HN API error: ${response.status} ${response.statusText}`);
    }
    return await response.json();
  }