block-kit

Slack Block Kit

Make useful Slack replies feel native. When structure or one-click follow-up improves the outcome, send a rich message without waiting for the user to ask for Block Kit.

Choose the surface

Use a presentation when the reply has at least one of these shapes:

• a decision, confirmation, or next action that belongs on buttons or a select
• a status, comparison, report, or plan that scans better as titled sections, a table, or a chart
• important context that should be visually separated from the primary result

Use plain text for short answers and casual conversation where structure adds no value.

Send the result

For a reply in Slack, call the message tool with action: "send" and a portable presentation. The Slack plugin renders it as native Block Kit. Use the exact schema exposed by the current tool; supported block types can include text, context, divider, buttons, select, chart, and table.

• Put the outcome first. Keep titles, labels, and context concise.
• Give interactive controls real follow-up semantics. Use typed callback actions for conversational choices and url for an external destination. Do not use generic command actions for Slack controls; Slack renders them as text fallback rather than clickable controls.
• Include a useful message fallback that preserves the meaning without the rich layout.
• After the visible send succeeds, do not repeat the same content in the final response.

A control is complete only when its value is self-contained enough for the next agent turn to understand and act on. When an interaction returns, acknowledge the choice visibly and continue the requested workflow.

Native Block Kit authoring

When the user is building a Slack app or explicitly requests raw Block Kit JSON, read the adapted official Block Kit guide in full. For common message, modal, and App Home layouts, also read the official patterns.

Follow the adapted guide's live-documentation and blocks.validate workflow for native JSON. Do not pass native Slack blocks to OpenClaw's presentation field; the plugin owns that conversion.