slack-message-formatter

Productivity

Format messages for Slack with pixel-perfect accuracy. Converts Markdown to rich HTML (for copy-paste into Slack) or Slack mrkdwn (for API/webhook). Use when the user asks to write a Slack message, announcement, or notification, format something "for Slack", preview how content looks in Slack, or send a message via Slack webhook. Also trigger when user mentions Slack formatting, mrkdwn, or wants to share Markdown content in Slack channels.

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Source SKILL.md: https://github.com/davepoon/buildwithclaude/blob/HEAD/plugins/all-skills/skills/slack-message-formatter/SKILL.md

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

Slack Message Formatter

Format messages for Slack with pixel-perfect accuracy. Converts Markdown to Slack-compatible output with two delivery paths:

Copy-paste — Rich HTML that preserves formatting when pasted into Slack's compose box
API/Webhook — Slack mrkdwn syntax for bots, automation, and CI/CD

When to Use This Skill

User asks to write a Slack message, announcement, or notification
User asks to format something "for Slack"
User wants to preview how a message will look in Slack
User wants to send a message via Slack webhook
User has Markdown content they want to share in Slack

What This Skill Does

Generates content in Markdown — Claude writes the message in standard Markdown, its native format
Converts to Rich HTML — Transforms Markdown into rich HTML that preserves formatting when pasted into Slack's compose box
Converts to Slack mrkdwn — Transforms Markdown into Slack's proprietary mrkdwn syntax for API/webhook delivery
Generates a Slack-themed preview — Creates an HTML preview page styled like the Slack UI and opens it in the browser
Copies to clipboard — Automatically copies the rich HTML to the system clipboard for one-step paste into Slack

How to Use

Basic Usage

Write a Slack message announcing our Q2 product launch

Format this for Slack: We shipped 3 new features this week...

Create a Slack announcement for the engineering team about the new CI pipeline

Webhook/API Delivery

Send a deploy notification to Slack via webhook

Formatting Features

The converter handles all Markdown features and translates them correctly for Slack:

Bold, italic, strikethrough, inline code
Links and headings (converted to bold in Slack)
Tables (rich HTML tables for paste, code blocks for API)
Task lists with emoji checkboxes
Nested lists and blockquotes
Code blocks with syntax highlighting
Slack mentions (<@U012AB3CD>, <!here>, <!channel>)
150+ emoji shortcodes converted to Unicode

Example

User: "Write a Slack message announcing our new feature"

Output (opened as a Slack-themed preview in the browser + copied to clipboard):

The preview shows a pixel-perfect Slack UI rendering. The user pastes directly into Slack with Cmd+V / Ctrl+V and the formatting is preserved.

User: "Send a deploy notification to our #deploys channel via webhook"

Output (sent via mrkdwn to the configured webhook):

*:rocket: Deploy Successful*

*Service:* payment-api
*Version:* v2.5.1
*Environment:* production
*Duration:* 47s

:white_check_mark: All health checks passing

Configuration

Env Variable	Default	Description
`SLACK_FORMATTER_CLIPBOARD`	`true`	Set to `false` to disable auto-clipboard copy
`SLACK_FORMATTER_PREVIEW_DIR`	`/tmp/slack-formatter`	Directory for preview HTML files
`CCH_SLA_WEBHOOK`	(none)	Slack webhook URL for sending messages

Tips

Always let the converter handle the Markdown-to-Slack translation; never write mrkdwn or HTML by hand
Slack mentions (<@U...>, <#C...>, <!here>) can be included directly in the Markdown
Tables work beautifully via the copy-paste path; for API delivery they become code blocks (Slack has no table syntax)
Preview files are timestamped so you can revisit them from conversation history