A Claude Code skill that enables proper formatting of messages for Slack using "mrkdwn" syntax.
Slack uses its own markdown variant called "mrkdwn" which differs significantly from standard markdown. This skill provides Claude Code with the correct syntax and best practices for formatting messages that will display properly in Slack.
When you ask Claude Code to format messages for Slack, this skill automatically:
- Converts standard markdown to Slack's mrkdwn syntax
- Applies correct formatting for bold, italic, strikethrough, and code
- Uses Slack's unique link syntax (
<url|text>) - Handles Slack-specific features (user mentions, channel links, special mentions)
- Provides guidance on when to use Block Kit for rich messages
- Avoids unsupported features (headings, tables, etc.)
- Download this repository
- Copy to your Claude Code skills directory:
cp -r slack-markdown-formatter ~/.claude/skills/ - The skill will automatically activate when you ask Claude to format Slack messages
- Download the latest
slack-markdown-formatter.zipfrom Releases - Extract to
~/.claude/skills/ - The skill is ready to use
Once installed, the skill automatically triggers when you:
- Ask to format messages for Slack
- Request Slack notifications
- Mention Slack Block Kit
- Need to convert markdown to Slack format
Simple formatting:
You: Format this for Slack: Check out **this article** on _productivity_
Claude: Check out *this article* on _productivity_
With links:
You: Create a Slack message linking to our docs
Claude: See our <https://docs.example.com|documentation> for details
Notifications:
You: Write a Slack deployment notification
Claude: <!here> :rocket: *Deployment Complete*
Version 2.1.0 has been deployed to production.
<https://github.com/org/repo/releases/v2.1.0|View Release Notes>
The main skill file containing:
- Overview and usage guidelines
- Core syntax differences from standard markdown
- Slack-specific features (mentions, channels, dates)
- Workflow for formatting messages
- Practical examples
- Block Kit integration guidance
Comprehensive reference documentation with:
- Complete syntax comparison tables
- Official documentation links
- Edge cases and limitations
- Best practices
- Common mistakes and solutions
- Quick reference card
| Feature | Standard Markdown | Slack mrkdwn |
|---|---|---|
| Bold | **text** |
*text* |
| Italic | *text* |
_text_ |
| Strikethrough | ~~text~~ |
~text~ |
| Link | [text](url) |
<url|text> |
| User Mention | N/A | <@U12345678> |
| Channel Link | N/A | <#C12345678> |
| Special Mention | N/A | <!here> <!channel> |
These standard markdown features don't work in Slack:
- Headings (
#,##, etc.) - Tables
- HTML tags
- Image embedding with
 - Nested formatting
- Task lists
For rich, interactive messages with:
- Structured layouts
- Buttons and interactive elements
- Images and media
- Forms and inputs
Use Slack's Block Kit instead of plain mrkdwn. The skill provides guidance on when and how to use Block Kit.
Contributions are welcome! If you find issues or have suggestions:
- Open an issue describing the problem or enhancement
- Submit a pull request with improvements
- Share your use cases and examples
MIT License - See LICENSE for details
This is a skill for Claude Code, Anthropic's official CLI tool. Skills extend Claude's capabilities with specialized knowledge and workflows.
Learn more about creating skills in the Claude Code documentation.
Created by @sirkitree
Note: This skill teaches Claude Code the correct Slack formatting syntax. It does not send messages to Slack directly - you'll need to copy the formatted output into Slack or use Slack's API for programmatic posting.