Reddit MCP Server

Instructions

Implementation Reference

• src/index.ts:171-178 (registration)

  Registration of the 'get_trending_subreddits' tool in the MCP server's ListTools response, including name, description, and empty input schema.

  {
    name: "get_trending_subreddits",
    description: "Get currently trending subreddits",
    inputSchema: {
      type: "object",
      properties: {},
    },
  },

• src/index.ts:451-452 (handler)

  MCP server CallToolRequest handler that dispatches the 'get_trending_subreddits' tool call to the implementation.

  case "get_trending_subreddits":
    return await tools.getTrendingSubreddits();

• src/tools/subreddit-tools.ts:70-105 (handler)

  Main tool handler function that orchestrates the call to Reddit client, handles errors, and formats the MCP response with a numbered list of trending subreddits.

  export async function getTrendingSubreddits() {
    const client = getRedditClient();
  
    if (!client) {
      throw new McpError(
        ErrorCode.InternalError,
        "Reddit client not initialized"
      );
    }
  
    try {
      console.log("[Tool] Getting trending subreddits");
      const trendingSubreddits = await client.getTrendingSubreddits();
  
      return {
        content: [
          {
            type: "text",
            text: `
  # Trending Subreddits
  
  ${trendingSubreddits
    .map((subreddit, index) => `${index + 1}. r/${subreddit}`)
    .join("\n")}
            `,
          },
        ],
      };
    } catch (error) {
      console.error(`[Error] Error getting trending subreddits: ${error}`);
      throw new McpError(
        ErrorCode.InternalError,
        `Failed to fetch trending subreddits: ${error}`
      );
    }
  }

• src/client/reddit-client.ts:254-268 (helper)

  RedditClient helper method that performs the actual API request to Reddit's /subreddits/popular.json endpoint to retrieve popular (trending) subreddit names.

  async getTrendingSubreddits(limit: number = 5): Promise<string[]> {
    await this.authenticate();
    try {
      const response = await this.api.get("/subreddits/popular.json", {
        params: { limit },
      });
  
      return response.data.data.children.map(
        (child: any) => child.data.display_name
      );
    } catch (error) {
      console.error("[Error] Failed to get trending subreddits:", error);
      throw new Error("Failed to get trending subreddits");
    }
  }