Slack MCP Server

Instructions

Implementation Reference

• slack_mcp/server.py:795-847 (handler)

  The handler function for the 'send_notification_message' tool. It constructs a Block Kit message with a status emoji and color-coded notification, sends it to the specified Slack channel using SlackClient.send_message, and returns the API response as JSON.

  @mcp.tool()
  async def send_notification_message(
      channel: str,
      status: str,
      title: str,
      description: str,
      details: Optional[str] = None,
      thread_ts: Optional[str] = None
  ) -> str:
      """
      Send a structured notification message with status indicator.
  
      Args:
          channel: Channel ID or name
          status: Status type (success, warning, error, info)
          title: Notification title
          description: Main description
          details: Additional details (optional)
          thread_ts: Thread timestamp for replies (optional)
      """
      try:
          # Status emojis and colors
          status_config = {
              "success": {"emoji": "✅", "color": "#28a745"},
              "warning": {"emoji": "⚠️", "color": "#ffc107"},
              "error": {"emoji": "❌", "color": "#dc3545"},
              "info": {"emoji": "ℹ️", "color": "#17a2b8"}
          }
          
          config = status_config.get(status.lower(), status_config["info"])
          
          blocks = [
              {
                  "type": "section",
                  "text": {
                      "type": "mrkdwn",
                      "text": f"{config['emoji']} *{title}*\n{description}"
                  }
              }
          ]
          
          if details:
              blocks.append(BlockKitBuilder.divider())
              blocks.append(BlockKitBuilder.context([details]))
          
          fallback_text = f"{config['emoji']} {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)

• slack_mcp/server.py:795-795 (registration)

  The @mcp.tool() decorator registers the send_notification_message function as an MCP tool.

  @mcp.tool()

• slack_mcp/server.py:804-814 (schema)

  Input schema defined by function parameters and detailed in the docstring.

  """
  Send a structured notification message with status indicator.
  
  Args:
      channel: Channel ID or name
      status: Status type (success, warning, error, info)
      title: Notification title
      description: Main description
      details: Additional details (optional)
      thread_ts: Thread timestamp for replies (optional)
  """

• slack_mcp/server.py:102-115 (helper)

  SlackClient.send_message method used by the tool to post the notification to Slack API.

  async def send_message(
      self, channel: str, text: str, thread_ts: Optional[str] = None, blocks: Optional[List[Dict[str, Any]]] = None
  ) -> Dict[str, Any]:
      """Send a message to a channel."""
      data = {"channel": channel, "text": text}
  
      if thread_ts:
          data["thread_ts"] = thread_ts
  
      if blocks:
          data["blocks"] = blocks
  
      return await self._make_request("POST", "chat.postMessage", json_data=data)