Zulip MCP Server

Instructions

Implementation Reference

• index.ts:498-507 (handler)

  The handler function within the CallToolRequest switch statement that executes the zulip_subscribe_to_channel tool. It validates the input arguments and calls the ZulipClient's subscribeToStream method to perform the subscription.

  case "zulip_subscribe_to_channel": {
    const args = request.params.arguments as unknown as SubscribeToChannelArgs;
    if (!args.channel_name) {
      throw new Error("Missing required argument: channel_name");
    }
    const response = await zulipClient.subscribeToStream(args.channel_name);
    return {
      content: [{ type: "text", text: JSON.stringify(response) }],
    };
  }

• index.ts:203-212 (schema)

  JSON Schema defining the input parameters for the zulip_subscribe_to_channel tool, specifying channel_name as a required string.

  inputSchema: {
    type: "object",
    properties: {
      channel_name: {
        type: "string",
        description: "The name of the stream to subscribe to",
      },
    },
    required: ["channel_name"],
  },

• index.ts:200-213 (registration)

  The Tool object registration that defines the name, description, and input schema for zulip_subscribe_to_channel, used in ListToolsRequest response.

  const subscribeToChannelTool: Tool = {
    name: "zulip_subscribe_to_channel",
    description: "Subscribe the bot to a channel (stream)",
    inputSchema: {
      type: "object",
      properties: {
        channel_name: {
          type: "string",
          description: "The name of the stream to subscribe to",
        },
      },
      required: ["channel_name"],
    },
  };

• index.ts:345-353 (helper)

  Helper method in ZulipClient class that performs the actual Zulip API call to subscribe to the specified stream/channel.

  async subscribeToStream(streamName: string) {
    try {
      const subscriptions = [{ name: streamName }];
      return await this.client.streams.subscribe({ subscriptions: JSON.stringify(subscriptions) });
    } catch (error) {
      console.error("Error subscribing to stream:", error);
      throw error;
    }
  }

• index.ts:62-64 (schema)

  TypeScript interface used for type-checking the tool's input arguments in the handler.

  interface SubscribeToChannelArgs {
    channel_name: string;
  }