MCP Hacker News

Instructions

Implementation Reference

• src/tools.ts:371-412 (handler)

  The execute handler for the 'getItem' tool, which fetches the specific Hacker News item by ID using fetchFromAPI, formats its properties including time and HN URL, and returns a structured JSON response.

  execute: async (args: any) => {
    const item = await fetchFromAPI<HackerNewsItem>(`/item/${args.id}`);
  
    if (!item) {
      return {
        content: [
          { type: "text", text: JSON.stringify({ error: "Item not found" }) },
        ],
      };
    }
  
    const formattedItem = {
      id: item.id,
      type: item.type,
      title: item.title,
      url: item.url,
      score: item.score,
      author: item.by,
      time: item.time ? formatTime(item.time) : "unknown",
      comments: item.descendants || 0,
      text: item.text,
      parent: item.parent,
      kids: item.kids,
      hnUrl: `https://news.ycombinator.com/item?id=${item.id}`,
    };
  
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(
            {
              message: `Item ${args.id}`,
              item: formattedItem,
            },
            null,
            2
          ),
        },
      ],
    };
  },

• src/tools.ts:361-370 (schema)

  Input schema for 'getItem' tool, requiring a numeric 'id' parameter.

  inputSchema: {
    type: "object",
    properties: {
      id: {
        type: "number",
        description: "The item ID to fetch",
      },
    },
    required: ["id"],
  },

• src/tools.ts:358-413 (registration)

  The complete 'getItem' tool object registered in the exported 'tools' array, which is imported and used by the MCP server in index.ts for tool listing and execution.

  {
    name: "getItem",
    description: "Get a specific item (story, comment, job, etc.) by ID",
    inputSchema: {
      type: "object",
      properties: {
        id: {
          type: "number",
          description: "The item ID to fetch",
        },
      },
      required: ["id"],
    },
    execute: async (args: any) => {
      const item = await fetchFromAPI<HackerNewsItem>(`/item/${args.id}`);
  
      if (!item) {
        return {
          content: [
            { type: "text", text: JSON.stringify({ error: "Item not found" }) },
          ],
        };
      }
  
      const formattedItem = {
        id: item.id,
        type: item.type,
        title: item.title,
        url: item.url,
        score: item.score,
        author: item.by,
        time: item.time ? formatTime(item.time) : "unknown",
        comments: item.descendants || 0,
        text: item.text,
        parent: item.parent,
        kids: item.kids,
        hnUrl: `https://news.ycombinator.com/item?id=${item.id}`,
      };
  
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(
              {
                message: `Item ${args.id}`,
                item: formattedItem,
              },
              null,
              2
            ),
          },
        ],
      };
    },
  },

• src/fetch-actions.ts:9-27 (helper)

  The fetchFromAPI helper function used by getItem to retrieve data from Hacker News API with caching support.

  export async function fetchFromAPI<T>(endpoint: string): Promise<T | null> {
    const cacheKey = endpoint;
    const cached = getCached<T>(cacheKey);
    if (cached) return cached;
  
    try {
      const response = await fetch(
        `https://hacker-news.firebaseio.com/v0${endpoint}.json`
      );
      if (!response.ok) throw new Error(`HTTP ${response.status}`);
  
      const data = await response.json();
      setCache(cacheKey, data);
      return data;
    } catch (error) {
      console.error(`Error fetching ${endpoint}:`, error);
      return null;
    }
  }