What is slack-mcp-server CLAUDE.md?

A Claude Code instruction file for a TypeScript MCP server that provides standardized access to selected Slack APIs. It also documents its commands, schema validation, and development structure.

Guiding development of the Slack MCP server and its API request and response schemas.

It helps Claude understand how the Slack server is built and how to build, run, lint, format, and test changes consistently.

How bugzy-ai/slack-mcp-server configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to bugzy-ai/slack-mcp-server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/bugzy-ai/slack-mcp-server/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/bugzy-ai/slack-mcp-server

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/bugzy-ai/slack-mcp-server/claude-md/github.svg)](https://agentmods.dev/instructions/bugzy-ai/slack-mcp-server/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/bugzy-ai/slack-mcp-server/claude-md"><img src="https://agentmods.dev/badge/instructions/bugzy-ai/slack-mcp-server/claude-md/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/instructions/bugzy-ai/slack-mcp-server/claude-md"><img src="https://agentmods.dev/badge/instructions/bugzy-ai/slack-mcp-server/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 879 This file is loaded in full into every session.

When invoked 879 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin fork From a forked repository.

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	$0.00879	$0.00879
Opus 5.5	$0.00352	$0.00352
Sonnet 5.5	$0.00176	$0.00176
Haiku 4.5	$0.00088	$0.00088

Measured 2mo ago against content hash ca6efa429e18, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

slack-mcp-server 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 2mo 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.

CLAUDE.md · 99 lines

How it starts

The opening of the file, as written. The whole thing — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

This is a simplified Model Context Protocol (MCP) server that provides AI assistants with standardized access to essential Slack APIs. It's written in TypeScript and uses only stdio transport for direct integration.

Development Commands

Building and Running

npm run build - Compile TypeScript to JavaScript in /dist
npm run dev - Start server in development mode with hot reloading
npm start - Run the production build

Code Quality

npm run lint - Run both ESLint and Prettier checks
npm run fix - Auto-fix all linting issues
npm run lint:eslint - Run ESLint only
npm run lint:prettier - Run Prettier only

Examples

npm run examples - Run stdio transport example

Architecture

Core Structure

The server follows a simplified schema-driven design pattern:

Request/Response Schemas (src/schemas.ts):
- All Slack API interactions are validated with Zod schemas
- Request schemas define input parameters
- Response schemas filter API responses to only necessary fields
Main Server (src/index.ts):
- Stdio-only transport for CLI integration
- Tool registration and request handling
- Single environment variable validation (bot token only)

Transport Mode

Stdio only: For CLI integration (Claude Desktop, etc.)

Available Tools

All tools follow the pattern: validate request → call Slack API → parse response → return JSON

Core messaging and channel tools (6 total):

slack_list_channels - List public channels with pagination
slack_post_message - Post messages to channels
slack_reply_to_thread - Reply to message threads
slack_add_reaction - Add emoji reactions to messages
slack_get_channel_history - Get message history from channels
slack_get_thread_replies - Get all replies in threads

Environment Requirements

Must set in environment or .env file:

SLACK_BOT_TOKEN: Bot User OAuth Token (only token required)

Read the full file on GitHub · 99 lines

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.

2mo ago First seen · 99 lines · 879 tokens per session scan A ca6efa429e18

Subscribe to this mod's changes

slack-mcp-server CLAUDE.md is an instructions file published in the GitHub repository bugzy-ai/slack-mcp-server (0 stars, last pushed 10mo ago), licensed Apache-2.0. It adds 879 tokens to every session, about $0.0035 per session on Opus 5.5. A static security scan graded it A with 0 findings. It comes from a forked repository.

Building agents

slack-mcp-server CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
slack-mcp-server CLAUDE.mdbugzy-ai/slack-mcp-server	Instructions file	0	10mo ago	Apache-2.0	A	879	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	9,719	GitHub Copilot
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	5,516	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	today	MIT	A	4,680	Codex, OpenCode
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	3,093	GitHub Copilot
vscode model-prompts.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	2,022	GitHub Copilot

slack-mcp-server: Instructions file for Claude Code