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.
npx skills add itseffi/agentic-os --skill slack-message-checkgit clone --depth 1 https://github.com/itseffi/agentic-osWrote 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.
[](https://agentmods.dev/skills/itseffi/agentic-os/slack-message-check)<a href="https://agentmods.dev/skills/itseffi/agentic-os/slack-message-check"><img src="https://agentmods.dev/badge/skills/itseffi/agentic-os/slack-message-check/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.
<a href="https://agentmods.dev/skills/itseffi/agentic-os/slack-message-check"><img src="https://agentmods.dev/badge/skills/itseffi/agentic-os/slack-message-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00025 | $0.00415 |
| Opus 5.5 | $0.00010 | $0.00166 |
| Sonnet 5.5 | $0.00005 | $0.00083 |
| Haiku 4.5 | $0.00003 | $0.00042 |
Grade A, and why
slack-message-check 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- slack-message-check — 89% identical, 8 lines differ
What it actually says
Slack Message Check
Check Slack channels for important messages and summarize activity.
Instructions
Step 1: List Relevant Channels
Call slack_list_channels to see available channels.
Step 2: Check Priority Channels
For each important channel (determined by user preferences or channel activity):
- Call
slack_get_channel_historywith limit of 20 messages - Filter for messages since last check
Step 3: Summarize Activity
Present findings to user:
Slack activity since yesterday:
**#general** (3 new messages)
- @alice mentioned the deployment schedule
**#engineering** (12 new messages)
- Discussion about API changes
- @bob asked for review on PR #234
**DMs** (2 unread)
- @carol: Question about meeting time
Step 4: Offer Actions
| Option | Description |
|---|---|
| Create task | Turn a message into a task |
| Reply | Draft a response |
| Mark read | Continue without action |
Step 5: Continue Daily Flow
After Slack check, continue with normal planning workflow.
Example Flow
User: "What should I work on today?"
Agent:
- Checks Slack for new activity
- "You have 5 new messages across 2 channels..."
- Summarizes key items
- Offers to create tasks from actionable messages
- Continues with task planning
Notes
- Focus on actionable messages, not all activity
- Prioritize DMs and mentions over general channel noise
- Respect user's channel preferences if configured
When to Use
Use this skill when the task directly matches the workflow described above.
When Not to Use
Do not use this skill when the request is unrelated, low-stakes, or better handled by a simpler direct response.
What ships with it
1 file 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.
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.
- 1mo ago First seen · 76 lines · 25 tokens per session scan A 9ddbb4df332c
slack-message-check is a skill published in the GitHub repository itseffi/agentic-os (117 stars, last pushed 15d ago), licensed MIT. It adds 25 tokens to every session and 415 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 2026-08-30.
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