Hacker News MCP Server

Instructions

Implementation Reference

• src/index.ts:360-415 (handler)

  Handler for getComments tool: validates input, fetches story kids, retrieves top limit comments, formats and returns them as text.

  case "getComments": {
    const validatedArgs = validateInput(CommentsRequestSchema, args);
    const { storyId, limit = 30 } = validatedArgs;
    try {
      const story = await hnApi.getItem(storyId);
  
      if (!story || !story.kids || story.kids.length === 0) {
        return {
          content: [
            {
              type: "text",
              text: `No comments found for story ID: ${storyId}`,
            },
          ],
        };
      }
  
      const commentIds = story.kids.slice(0, limit);
      const comments = await hnApi.getItems(commentIds);
      const formattedComments = comments
        .filter((item) => item && item.type === "comment")
        .map(formatComment);
  
      if (formattedComments.length === 0) {
        return {
          content: [
            {
              type: "text",
              text: `No comments found for story ID: ${storyId}`,
            },
          ],
        };
      }
  
      const text =
        `Comments for Story ID: ${storyId}\n\n` +
        formattedComments
          .map(
            (comment, index) =>
              `${index + 1}. Comment by ${comment.by} (ID: ${
                comment.id
              }):\n` + `   ${comment.text}\n\n`
          )
          .join("");
  
      return {
        content: [{ type: "text", text: text.trim() }],
      };
    } catch (err) {
      const error = err as Error;
      throw new McpError(
        ErrorCode.InternalError,
        `Failed to fetch comments: ${error.message}`
      );
    }
  }

• src/schemas/index.ts:53-56 (schema)

  Input schema for getComments tool using Zod validation.

  export const CommentsRequestSchema = z.object({
    storyId: z.number().int().positive(),
    limit: z.number().int().min(1).max(100).default(30),
  });

• src/index.ts:123-138 (registration)

  Tool registration in ListTools response, including name, description, and input schema.

  {
    name: "getComments",
    description: "Get comments for a story",
    inputSchema: {
      type: "object",
      properties: {
        storyId: { type: "number", description: "The ID of the story" },
        limit: {
          type: "number",
          description: "The maximum number of comments to fetch",
          default: 30,
        },
      },
      required: ["storyId"],
    },
  },

• src/models/comment.ts:11-21 (helper)

  Helper function to format raw comment data into structured Comment object, used in getComments handler.

  export function formatComment(item: any): Comment {
    return {
      id: item.id,
      text: item.text || "",
      by: item.by || "deleted",
      time: item.time,
      parent: item.parent,
      kids: item.kids || [],
      type: "comment",
    };
  }