slack-reaction-action

slack-reaction-action is a skill for Claude Code from burin-labs/harn. It costs 15 tokens per session (77 once invoked), scanned A, original, Apache-2.0.

A recipe for handling Slack reaction-added events through the Slack Events API. It includes a place to customize what happens when someone adds a reaction.

In plain words
What is it for?
Use it to create tasks, route review requests, or post replies when users react to Slack messages.
Why use it?
It provides a starting point for turning Slack reactions into application workflows while leaving provider verification in the connector.

Skill for Claude Code

Written for Claude Code: when-to-use in frontmatter.

Good fit Use it to create tasks, route review requests, or post replies when users react to Slack messages.

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Install with agentmods
npx agentmods add skills/burin-labs/harn/slack-reaction-action
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 burin-labs/harn --skill slack-reaction-action
Clone the repo
git clone --depth 1 https://github.com/burin-labs/harn

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 slack-reaction-action

README.md
[![agentmods](https://agentmods.dev/badge/skills/burin-labs/harn/slack-reaction-action/github.svg)](https://agentmods.dev/skills/burin-labs/harn/slack-reaction-action)
Your own site
<a href="https://agentmods.dev/skills/burin-labs/harn/slack-reaction-action"><img src="https://agentmods.dev/badge/skills/burin-labs/harn/slack-reaction-action/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 slack-reaction-action

Your own site · 80×15
<a href="https://agentmods.dev/skills/burin-labs/harn/slack-reaction-action"><img src="https://agentmods.dev/badge/skills/burin-labs/harn/slack-reaction-action.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 77 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.
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 $0.00015 $0.00077
Opus 5 $0.00008 $0.00039
Sonnet 5 $0.00003 $0.00015
Haiku 4.5 $0.00002 $0.00008

Measured 7d ago against content hash 59897595582d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

slack-reaction-action 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 7d 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.

examples/triggers/slack-reaction-action/SKILL.md · 11 lines

What it actually says

Slack reaction action

Keep Slack URL verification and signing in the connector. Customize on_reaction to create tasks, route review requests, or post replies.

Files

What ships with it

3 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. 7d ago First seen · 11 lines · 15 tokens per session scan A 59897595582d

Subscribe to this mod's changes

slack-reaction-action is a skill published in the GitHub repository burin-labs/harn (21 stars, last pushed yesterday), licensed Apache-2.0. It adds 15 tokens to every session and 77 once invoked, about $0.0001 per session on Opus 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 2026-09-03.