slack

name	slack
description	Use when posting, replying, or sending a DM in Slack, or when the user mentions Slack, a Slack channel, a Slack thread, or a Slack message URL. Covers the `slack-post` helper, its target forms, and channel resolution. Use even if the user only says 'post this in Slack', 'reply in the thread', or 'DM them'.
user-invocable	true

Slack

Read with the Slack MCP tools. Write with slack-post.

Do not use slack_send_message, slack_send_message_draft, slack_schedule_message, or slack_update_canvas. Read, search, and reaction tools are fine.

slack-post

slack-post <target> --body-file PATH [--thread-ts TS]
slack-post <message-url> --body-file PATH

Target	Result
C0ABEN38TRB	Post at the top of that channel or DM
'#eng-fulfillment-automation'	Post to a public channel by name
U08V6EV65TQ	DM that person
https://acme.slack.com/archives/C.../p1785267943715149	Reply inside that message's thread

Pass a message URL unchanged. Never hand-convert the p1785267943715149 path timestamp.

Where slack-post is missing, print the command for the operator to run.

Rules

Keep it short. Slack is chat, not a document. One or two sentences is normal. No headings, no bullet lists, no sign-off. Nobody wants an essay in Slack, and a long message reads as generated even when every fact in it is right.

Resolve a channel name to an ID first with slack_search_channels. A name only reaches a public channel.

Write the body to a file. Quotes, backticks, and newlines survive.

Reply in the thread when the target is a thread.

Load and follow the communication-rules skill before drafting.

Load contribution-voice before drafting. Anything posted publishes under the user's name. Run its cut pass, then cut again for Slack.

Report the ts that slack-post prints.