[BUG] Slack MCP draft messages do not format lists, while sent messages do

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Slack connector: slack_send_message_draft flattens all list formatting; slack_send_message does not.
Any draft-for-human-review workflow loses list formatting, forcing manual re-formatting before sending.

• Feedback ID: 59cbd311-43de-4edc-8953-1a06f469ccfc

Errors
Draft renders literal "•" text characters (numbered lists also flatten). Passing a Block Kit {"blocks":[...]} payload as the message string renders as literal JSON.

What Should Happen?

Draft should contain a native Slack bulleted list, like the sent message does.

Steps to Reproduce

1. have a Slack MCP setup
2. Call slack_send_message_draft tool with markdown: - item one\n- item two. You can just ask Claude to "send - item one\n- item two to myself as a draft Slack message.
3. Look at Slack and note that the draft message only shows raw unicode bullets, not a real list. You can easily see it by editing the draft to add a real list below; the alignment isn't the same.

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.236

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_