Slack MCP Server

Instructions

Implementation Reference

• slack_mcp/server.py:893-942 (handler)

  The primary handler function for the 'send_interactive_message' MCP tool. Decorated with @mcp.tool() for registration. Parses button JSON, builds interactive Block Kit blocks using BlockKitBuilder, and sends the message via SlackClient.

  @mcp.tool()
  async def send_interactive_message(
      channel: str,
      title: str,
      description: str,
      buttons: str,
      thread_ts: Optional[str] = None
  ) -> str:
      """
      Send an interactive message with buttons.
  
      Args:
          channel: Channel ID or name
          title: Message title
          description: Message description
          buttons: JSON string of button configurations [{"text": "Button Text", "action_id": "action_1", "style": "primary"}]
          thread_ts: Thread timestamp for replies (optional)
      """
      try:
          blocks = [
              BlockKitBuilder.header(title),
              BlockKitBuilder.section(description)
          ]
          
          # Parse button configurations
          button_configs = json.loads(buttons)
          button_elements = []
          
          for btn_config in button_configs:
              button = BlockKitBuilder.button(
                  text=btn_config["text"],
                  action_id=btn_config["action_id"],
                  value=btn_config.get("value"),
                  url=btn_config.get("url"),
                  style=btn_config.get("style")
              )
              button_elements.append(button)
          
          if button_elements:
              blocks.append(BlockKitBuilder.actions(*button_elements))
          
          fallback_text = f"{title}: {description}"
          
          client = SlackClient()
          result = await client.send_message(channel, fallback_text, thread_ts, blocks)
          return json.dumps(result, indent=2)
      except Exception as e:
          return json.dumps({"error": str(e)}, indent=2)