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Send a Slack message

Queue Slack rows or send one message typed on the command line.

Send a Slack message

Send a Slack message as yourself, from a queued row or typed on the command line. Both send under your captured session, with no app attached.

Before the first run

Capture your signed-in Slack session into the profile (Sign a profile in to each platform):

blowhorn profile auth --platform slack --profile kate

Send one message, no row

Name one profile, the destination, and the text, and preview it first:

blowhorn post --platform slack --profile kate --target "#announcements" --message "Maintenance is complete" --dry-run
blowhorn post --platform slack --profile kate --target "#announcements" --message "Maintenance is complete"

--target takes #channel, @user, a Slack channel link, or a Slack message link (a thread reply). For a one-off message anything else is refused, never sent somewhere you did not name. Give a link when the profile's credentials are per workspace, so Blowhorn knows which workspace to send with. --target without --message is not a one-off message: it redirects the queued Slack rows for that run.

Nothing is written back, so running the command twice sends the message twice.

Send the queued rows

Queue rows with Platform set to Slack. Put where each message goes in Amplify (#channel, @user, or a Slack channel or message link), or a Slack message link in Comment on for a thread reply. Destination only picks the workspace whose credentials send. Then run:

blowhorn post --platform slack --profile kate

A row with no target in Amplify or Comment on goes to #general, and so does one whose target Blowhorn cannot read, such as announcements without the #. Preview with --dry-run first.

--target on that run sends the queued rows to that destination instead of their own. Unlike a one-off message, it is not checked: a value it cannot read sends every queued row to #general.

Pick which credential sends

--slack-auth names which Slack credential may send for one run: session (your captured signed-in session), user-token, or bot-token, or a comma-delimited list of them.

Last modified October 9, 2026: docs: sync from master (5f4e718)