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 agentmods add instructions/aaronsb/slack-mcp/claude-mdgit clone --depth 1 https://github.com/aaronsb/slack-mcpWrote 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/instructions/aaronsb/slack-mcp/claude-md)<a href="https://agentmods.dev/instructions/aaronsb/slack-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/aaronsb/slack-mcp/claude-md.svg" alt="Measured on agentmods" 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 | $0.00674 | $0.00674 |
| Opus 5 | $0.00337 | $0.00337 |
| Sonnet 5 | $0.00135 | $0.00135 |
| Haiku 4.5 | $0.00067 | $0.00067 |
Grade A, and why
slack-mcp CLAUDE.md 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 54 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Slack MCP Server
Go-based MCP server for Slack workspace interaction using session tokens (xoxc/xoxd). No OAuth, no bot permissions, no admin approval.
Build
make build # Build for current platform
make build-all-platforms # Cross-compile (darwin/linux/windows x amd64/arm64)
make test # Run tests
make format # Format code
make tidy # Tidy go modules
make clean # Remove build artifacts
make npm-publish NPM_TOKEN=... # Publish to npm
Architecture
cmd/slack-mcp/— Entry point, transport selection (stdio/sse), setup commandpkg/server/— MCP server, tool registrationpkg/provider/— Slack API client, two-phase channel cachingpkg/features/— Tool implementationspkg/text/— Text processing utilitiesnpm/— npm wrapper packages (platform binary resolver)
Tools
| Tool | Kind | What it does |
|---|---|---|
inbox |
noun | What needs you: view='new' (since your last dismiss), 'unreads', 'mentions' |
messages |
noun | Conversation content: target= reads in full, +around= context, +since= time window, query= full Slack search syntax |
estate |
noun | Workspace shape and relationships: view='about'|'families'|'person'|'initiatives'|'convergence'|'people'|'channels' |
batch |
executor | Run a held plan of reads in one call: commands=[{tool, params}...]; playbooks via save=/run=/list=/delete= |
say |
verb | Contribute content (Slack-visible): a message, or an emoji reaction |
dismiss |
verb | Mark inbox items handled — private watermark, invisible to Slack |
mark-read |
verb | Fire read receipts — the one visibly-public read signal |
auth |
verb | Interactive token setup (localhost only) |
download |
verb | Download a shared file |
Verb encodes effect, noun encodes domain, parameter encodes scope (ADR-009); the batch executor encodes composition, never effect, and admits only the read nouns (ADR-010). Every noun echoes its effective parameters and pages every capped list.
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.
- 5d ago First seen · 54 lines · 674 tokens per session scan A 7a7e128d637b
slack-mcp CLAUDE.md is an instructions file published in the GitHub repository aaronsb/slack-mcp (2 stars, last pushed 15d ago), licensed MIT. It adds 674 tokens to every session, about $0.0034 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 2026-08-31.
Other instructions, from other repositories
slack-agent-cli AGENTS.md
Instructions for bcharleson/slack-agent-cli, covering slack agent cli — ai agent guide, quick start, install (requires node 18+ and python 3.10+), authenticate (non-interactive — best for agents) and verify.
ironcurtain CLAUDE.md
Claude Code instructions for provos/ironcurtain, covering claude.md, general workflow, git & worktrees, git workflow and platform considerations.
run402 AGENTS.md
AGENTS.md instructions for kychee-com/run402, covering agents.md, what this is, git workflow — worktrees, never branches, never stash, build & test commands and run all unit tests.
Task Execution Workflow
Rules for selecting, implementing, testing, and closing work in the Sir Thaddeus repository without requiring an external task tracker.
TimeTree-MCP CLAUDE.md
Claude Code instructions for ehs208/TimeTree-MCP, covering timetree mcp project guide, project purpose, current capabilities, architecture map and api behavior notes.
Harness Iteration Framework
Reusable workflow for running the full Sir Thaddeus E2E harness, breaking failures into stages, and iterating on product fixes with fast feedback.