Slack Messaging

anthropics/knowledge-work-pluginsOfficial

If you're tired of Slack messages that look broken because you used Markdown instead of mrkdwn, this is for you. It teaches Claude the weird syntax differences (single asterisks for bold, pipe-separated links in angle brackets, no header support) and pushes you toward better message structure. The guidance on leading with the point and using threads appropriately is solid. Most useful when you're drafting announcements or important messages where formatting actually matters. It won't make your meetings shorter, but at least your update posts will scan better on mobile.

skills.sh installs: 4K
GitHub stars: 35.3K
last updated: Aug 21, 2026

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Install

$ npx -y skills add anthropics/knowledge-work-plugins --skill slack-messaging --agent claude-code

Installs into .claude/skills of the current project.

Files

Slack Messaging Best Practices

This skill provides guidance for composing well-formatted, effective Slack messages.

When to Use

Apply this skill whenever composing, drafting, or helping the user write a Slack message — including when using slack_send_message, slack_send_message_draft, or slack_create_canvas.

Slack Formatting (mrkdwn)

Slack uses its own markup syntax called mrkdwn, which differs from standard Markdown. Always use mrkdwn when composing Slack messages:

Format	Syntax	Notes
Bold	`text`	Single asterisks, NOT double
Italic	`_text_`	Underscores
Strikethrough	`~text~`	Tildes
Code (inline)	`code`	Backticks
Code block	```code```	Triple backticks
Quote	`> text`	Angle bracket
Link	`<url\|display text>`	Pipe-separated in angle brackets
User mention	`<@U123456>`	User ID in angle brackets
Channel mention	`<#C123456>`	Channel ID in angle brackets
Bulleted list	`- item` or `• item`	Dash or bullet character
Numbered list	`1. item`	Number followed by period