mcp_slack

Instructions

Implementation Reference

• main.py:145-156 (handler)

  The handler function for the 'post_message' tool, which posts a message to a specified Slack channel using the Slack chat.postMessage API. Registered via @mcp.tool() decorator.

  @mcp.tool()
  async def post_message(channel_id: str, text: str) -> str:
      """Post a message to a Slack channel."""
      params = {
          "channel": channel_id,
          "text": text
      }
      data = await make_slack_request("chat.postMessage", params)
      if data and data.get("ok"):
          return "✅ Message posted successfully!"
      return f"❌ Failed to post message. Error: {data.get('error', 'Unknown')}"

• main.py:19-33 (helper)

  Helper utility function used by post_message to make authenticated HTTP requests to the Slack API.

  async def make_slack_request(method: str, params: dict[str, Any] | None = None) -> dict[str, Any] | None:
      """Make a request to the Slack Web API with proper error handling."""
      headers = {
          "Authorization": f"Bearer {SLACK_TOKEN}",
          "Content-Type": "application/x-www-form-urlencoded"
      }
      async with httpx.AsyncClient() as client:
          try:
              response = await client.post(f"{SLACK_API_BASE}/{method}", data=params, headers=headers, timeout=10.0)
              response.raise_for_status()
              return response.json()
          except Exception as e:
              print(f"Slack API error: {e}")
              return None