Send Slack Message
A building-block skill for posting formatted messages to Slack channels. Handles markdown-to-Slack conversion and channel resolution. Designed to be called by other skills.
Another piece of plumbing
Like the Send Email skill, this is a building block. It posts a formatted message to a Slack channel. On its own, that's not very interesting. Composed with other skills, it becomes the notification layer for everything.
A daily digest skill generates a summary, then calls this skill to post it to a channel. A scheduled job finishes, then posts a status update. A monitoring check finds something wrong, then alerts the team. The pattern is always the same: do the work, then tell someone about it.
What it handles
The tricky part of posting to Slack from a script isn't the API call -- it's the formatting. Slack uses its own markup format ("mrkdwn") that's similar to markdown but different in irritating ways. Bold is *text* instead of **text**, links are <url|text> instead of [text](url), and headings don't exist (you just bold them).
This skill handles that conversion so other skills can write standard markdown and not worry about Slack-specific formatting. It also handles channel name resolution (you say "post to my-channel" and it looks up the channel ID from a config file) and JSON escaping (which breaks silently if you get it wrong).
Where this is heading
With Claude Code's scheduling features, having a reliable "post to Slack" primitive means any skill can add notifications as a final step. Schedule a job to run every morning, have it fetch data, summarise it, and post the summary to a Slack channel -- all without writing a single line of integration code beyond this skill.
Setup
- Download the skill file below
- Create a directory:
~/.claude/skills/send-slack-message/ - Save the file as
SKILL.mdin that directory - Create a Slack bot at https://api.slack.com/apps with
chat:writepermission - Add your bot token and channel IDs to
~/.claude/slack-config.env - Invite the bot to each channel you want it to post to
Ready to use this skill?
Drop it into your .claude/skills/ folder and you're ready.
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