block-kit

block-kit is a skill for Claude Code from openclaw/openclaw. It costs 25 tokens per session (521 once invoked), scanned A, original, MIT.

A skill for creating and checking Slack Block Kit messages. Block Kit is Slack's JSON format for interactive messages with sections, buttons, and other layout elements.

In plain words
What is it for?
It is for writing or checking native Slack replies that use Block Kit.
Why use it?
It helps avoid manually assembling or validating Slack's structured message format.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: built for openclaw.

Good fit It is for writing or checking native Slack replies that use Block Kit.

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Install with agentmods
npx agentmods add skills/openclaw/openclaw/block-kit
About the project

OpenClaw is an AI assistant that runs on a user's own devices and connects to chat services such as Discord, Slack, Telegram, and WhatsApp. Individuals or teams use it for assistant tasks while keeping its state, memory, and credentials on their hardware and choosing the models or agent harnesses it uses. The catalogue entries are skills, agents, instructions, hooks, and settings that define or extend OpenClaw's workflow.

openclaw/openclaw · 392,311 stars · on GitHub · openclaw.ai

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add openclaw/openclaw --skill block-kit
Clone the repo
git clone --depth 1 https://github.com/openclaw/openclaw

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for block-kit

README.md
[![agentmods](https://agentmods.dev/badge/skills/openclaw/openclaw/block-kit/github.svg)](https://agentmods.dev/skills/openclaw/openclaw/block-kit)
Your own site
<a href="https://agentmods.dev/skills/openclaw/openclaw/block-kit"><img src="https://agentmods.dev/badge/skills/openclaw/openclaw/block-kit/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for block-kit

Your own site · 80×15
<a href="https://agentmods.dev/skills/openclaw/openclaw/block-kit"><img src="https://agentmods.dev/badge/skills/openclaw/openclaw/block-kit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 521 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00025 $0.00521
Opus 5.5 $0.00010 $0.00208
Sonnet 5.5 $0.00005 $0.00104
Haiku 4.5 $0.00003 $0.00052

Measured 1mo ago against content hash b9e7a6207b0b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

block-kit scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

extensions/slack/skills/block-kit/SKILL.md · 38 lines

How it starts

The opening of the file, as written. The whole thing — 38 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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.

Read the full file on GitHub · 38 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 38 lines · 25 tokens per session scan A b9e7a6207b0b

Subscribe to this mod's changes

block-kit is a skill published in the GitHub repository openclaw/openclaw (392,311 stars, last pushed today), licensed MIT. It adds 25 tokens to every session and 521 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-06.