What is slack-master?

A shared library of setup notes, API documentation, authentication guidance, error handling, and scripts for Slack-related skills. It is used by other skills rather than directly by users.

It supports skills that send messages, search Slack, manage channels, handle files, and perform other Slack workspace tasks.

It keeps common Slack information in one place so separate Slack skills do not repeat or drift apart.

slack-master — Skill for Claude Code and Codex by DorianSchlede

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 DorianSchlede/nexus-template --skill slack-master

Clone the repo

git clone --depth 1 https://github.com/DorianSchlede/nexus-template

Made for: Claude Code, Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/dorianschlede/nexus-template/slack-master/github.svg)](https://agentmods.dev/skills/dorianschlede/nexus-template/slack-master)

Your own site

<a href="https://agentmods.dev/skills/dorianschlede/nexus-template/slack-master"><img src="https://agentmods.dev/badge/skills/dorianschlede/nexus-template/slack-master/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/dorianschlede/nexus-template/slack-master"><img src="https://agentmods.dev/badge/skills/dorianschlede/nexus-template/slack-master.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,415 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.

Model	Per session	Once invoked
Fable 5.1	$0.00042	$0.02415
Opus 5	$0.00021	$0.01208
Sonnet 5	$0.00008	$0.00483
Haiku 4.5	$0.00004	$0.00242

Measured 8d ago against content hash f2c9d0400f64, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

slack-master 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 8d ago.

The scan reads SKILL.md. This mod also ships 39 executable files (scripts/add_reaction.py, scripts/channel_history.py, scripts/channel_info.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

00-system/skills/integrations/slack/slack-master/SKILL.md · 341 lines

How it starts

The opening of the file, as written. The whole thing — 341 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Slack Master

This is NOT a user-facing skill. It's a shared resource library referenced by Slack integration skills.

Purpose

Provides shared resources to eliminate duplication across:

slack-connect - Meta-skill for Slack workspace operations
slack-send-message - Send messages to channels/DMs
slack-list-channels - List available channels
slack-search-messages - Search message history
And 29 other operation skills...

Instead of loading this skill, users directly invoke the specific skill they need above.

Architecture: DRY Principle

Problem solved: Slack skills would have duplicated content (setup instructions, API docs, auth flow, error handling).

Solution: Extract shared content into slack-master/references/ and slack-master/scripts/, then reference from each skill.

Result: Single source of truth, reduced context per skill.

Authentication Model: User OAuth

This integration uses User OAuth (not Bot OAuth) for team-wide deployment:

┌─────────────────────────────────────────────────────────────┐
│  USER OAUTH (Per-User Authentication)                       │
├─────────────────────────────────────────────────────────────┤
│  • Each team member authenticates with their own account    │
│  • Messages sent appear as the user (not a bot)             │
│  • Users only see channels/DMs they have access to          │
│  • No cross-user data exposure possible                     │
│  • Token type: xoxp- (user tokens)                          │
└─────────────────────────────────────────────────────────────┘

Why User OAuth?

Messages appear from the actual user, not a bot
Respects existing channel permissions
No need for bot installation in every channel
Each user controls their own access

Shared Resources

All Slack skills reference these resources (progressive disclosure).

references/

setup-guide.md - Complete setup wizard

Creating a Slack App with User OAuth
Configuring OAuth scopes
Getting client ID and secret
Running the OAuth flow

Read the full file on GitHub · 341 lines

Files

What ships with it

43 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.

8d ago First seen · 341 lines · 42 tokens per session scan A f2c9d0400f64

Subscribe to this mod's changes

slack-master is a skill published in the GitHub repository DorianSchlede/nexus-template (8 stars, last pushed 7mo ago), licensed MIT. It adds 42 tokens to every session and 2,415 once invoked, about $0.0002 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.

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slack-master