MCP Server for Slack

Instructions

Implementation Reference

• index.ts:484-497 (handler)

  The switch case that handles the tool execution: validates arguments, calls SlackClient.getChannelHistory, and returns the JSON response.

  case "slack_get_channel_history": {
    const args = request.params
      .arguments as unknown as GetChannelHistoryArgs;
    if (!args.channel_id) {
      throw new Error("Missing required argument: channel_id");
    }
    const response = await slackClient.getChannelHistory(
      args.channel_id,
      args.limit,
    );
    return {
      content: [{ type: "text", text: JSON.stringify(response) }],
    };
  }

• index.ts:139-157 (schema)

  Tool schema definition including name, description, and input schema with properties for channel_id (required) and optional limit.

  const getChannelHistoryTool: Tool = {
    name: "slack_get_channel_history",
    description: "Get recent messages from a channel",
    inputSchema: {
      type: "object",
      properties: {
        channel_id: {
          type: "string",
          description: "The ID of the channel",
        },
        limit: {
          type: "number",
          description: "Number of messages to retrieve (default 10)",
          default: 10,
        },
      },
      required: ["channel_id"],
    },
  };

• index.ts:567-582 (registration)

  The listTools request handler that registers the tool by including it in the returned tools array.

  server.setRequestHandler(ListToolsRequestSchema, async () => {
    console.log("Received ListToolsRequest");
    return {
      tools: [
        listChannelsTool,
        postMessageTool,
        replyToThreadTool,
        addReactionTool,
        getChannelHistoryTool,
        getThreadRepliesTool,
        getUsersTool,
        getUserProfileTool,
        lookupUserByEmailTool,
      ],
    };
  });

• index.ts:322-337 (helper)

  SlackClient method that performs the actual API call to Slack's conversations.history endpoint to fetch channel history.

  async getChannelHistory(
    channel_id: string,
    limit: number = 10,
  ): Promise<any> {
    const params = new URLSearchParams({
      channel: channel_id,
      limit: limit.toString(),
    });
  
    const response = await fetch(
      `https://slack.com/api/conversations.history?${params}`,
      { headers: this.botHeaders },
    );
  
    return response.json();
  }