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Hi there!
I am using the Slack MCP server with tool mode = tools-only.
I am trying to send a simple message with the block kit (simple button), but it always sends a message without the button.
What am I missing here?
Thank you!
hey! not from the team, but I had the same issue.
the blocks attribute is dynamic and is only available after another property is configured. This is not supported by the tools-only mode. Either use the new full-config mode (haven’t tried it) or the sdk directly without MCP 
You’re running into a known limitation: Slack MCP server in tools-only mode does not support sending messages with Block Kit (interactive elements like buttons). In tools-only mode, only basic text messages are supported—Block Kit fields like blocks are ignored or stripped out. Why is this happening? - tools-only mode is intentionally limited for security and simplicity. It does not allow dynamic or advanced message formatting, including interactive buttons. - The blocks attribute is only enabled in other modes (like full-config). How to fix or work around this: 1. Switch to full-config mode if you want to send messages with Block Kit (buttons, select menus, etc.). This mode allows you to define the full message payload, including blocks. 2. Use the Slack SDK directly (bypassing MCP) if you need full control and interactivity. 3. If you must use MCP and only have access to tools-only, you are limited to plain text messages. Summary: You are not missing anything—this is a limitation of the tools-only mode. For Block Kit, use full-config mode or the Slack SDK directly. If you need more help or want to request support for Block Kit in tools-only mode, visit Support - Pipedream.
Thank you very much! I will try this out
Can you please share how to work with the full-config mode? I dont see any references in the docs, and it is not working out-of-the-box with Slack