Hacker News MCP Server

Instructions

Implementation Reference

• src/index.ts:417-463 (handler)

  The handler for the 'getCommentTree' tool. Validates the input using CommentTreeRequestSchema, fetches the story with comments using algoliaApi.getStoryWithComments, recursively formats the comment tree into a textual representation with indentation, and returns it as text content.

  case "getCommentTree": {
    const validatedArgs = validateInput(CommentTreeRequestSchema, args);
    const { storyId } = validatedArgs;
    try {
      const data = await algoliaApi.getStoryWithComments(storyId);
  
      if (!data || !data.children || data.children.length === 0) {
        return {
          content: [
            {
              type: "text",
              text: `No comments found for story ID: ${storyId}`,
            },
          ],
        };
      }
  
      const formatCommentTree = (comment: any, depth = 0): string => {
        const indent = "  ".repeat(depth);
        let text = `${indent}Comment by ${comment.author} (ID: ${comment.id}):\n`;
        text += `${indent}${comment.text}\n\n`;
  
        if (comment.children) {
          text += comment.children
            .map((child: any) => formatCommentTree(child, depth + 1))
            .join("");
        }
        return text;
      };
  
      const text =
        `Comment tree for Story ID: ${storyId}\n\n` +
        data.children
          .map((comment: any) => formatCommentTree(comment))
          .join("");
  
      return {
        content: [{ type: "text", text: text.trim() }],
      };
    } catch (err) {
      const error = err as Error;
      throw new McpError(
        ErrorCode.InternalError,
        `Failed to fetch comment tree: ${error.message}`
      );
    }
  }

• src/index.ts:139-149 (registration)

  Tool registration in the ListTools response, defining name, description, and input schema for getCommentTree.

  {
    name: "getCommentTree",
    description: "Get a comment tree for a story",
    inputSchema: {
      type: "object",
      properties: {
        storyId: { type: "number", description: "The ID of the story" },
      },
      required: ["storyId"],
    },
  },

• src/schemas/index.ts:58-60 (schema)

  Zod schema used for input validation of the getCommentTree tool, requiring a positive integer storyId.

  export const CommentTreeRequestSchema = z.object({
    storyId: z.number().int().positive(),
  });