Slack

Name: Slack
Author: aaronsb

by aaronsbversion 2.8.1i★ –iRuns on your computer

Registry nameio.github.aaronsb/slack-mcp

Install

Overview

Description from the maker (original English)

Read and write Slack with session tokens — no OAuth, no bot, no admin approval.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Chat & email

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: SLACK_MCP_XOXC_TOKEN, SLACK_MCP_XOXD_TOKEN

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "slack": {
      "command": "npx",
      "args": [
        "-y",
        "@aaronsb/slack-mcp"
      ],
      "env": {
        "SLACK_MCP_XOXC_TOKEN": "your-value",
        "SLACK_MCP_XOXD_TOKEN": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add slack --env SLACK_MCP_XOXC_TOKEN=your-value --env SLACK_MCP_XOXD_TOKEN=your-value -- npx -y @aaronsb/slack-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "slack": {
      "command": "npx",
      "args": [
        "-y",
        "@aaronsb/slack-mcp"
      ],
      "env": {
        "SLACK_MCP_XOXC_TOKEN": "your-value",
        "SLACK_MCP_XOXD_TOKEN": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "slack": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@aaronsb/slack-mcp"
      ],
      "env": {
        "SLACK_MCP_XOXC_TOKEN": "your-value",
        "SLACK_MCP_XOXD_TOKEN": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

SLACK_MCP_XOXC_TOKEN env
Slack session token. Optional — the auth tool extracts it from your browser and stores it in the config file.
SLACK_MCP_XOXD_TOKEN env
Slack session cookie. Optional — the auth tool extracts it from your browser and stores it in the config file.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account aaronsb, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Chat & emaili

More stars than 0% of the other 1777 servers in this category
Published to the registry more recently than 63% of the other 1777 servers in this category
Basic checks equal to or better than 100% of the other 1777 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Slack safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (2.8.1) reached the registry 17 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Vexa, emailmd, MCP WhatsApp Cloud

Alternatives

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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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MCP WhatsApp Cloud

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Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Slack MCP

MCP server that gives AI agents access to your Slack workspaces using session tokens. No OAuth apps, no bot permissions, no admin approval required.

Beyond reading and writing messages, it accumulates a durable picture of the workspace — every channel and user's state over time, departures kept as dated tombstones — and synthesizes a relationship graph from it on demand: estate view='about' person='X' answers "tell me about X" with their footprint, circle, and a ranked reading plan. The graph is never maintained as a store; it is computed per query from two small local ledgers that hold no message content (design note). Add render='graph' to draw one view as a static HTML page you open locally.

How it works

Slack MCP uses your existing browser session tokens (xoxc/xoxd) to interact with Slack on your behalf. It reads stealthily by default — only the mark-read tool triggers read receipts. Everything else is invisible to other users.

Token extraction is built into the binary. If you're logged into Slack in Chrome or Firefox, the setup flow can extract tokens automatically — no copy-pasting from DevTools.

Prerequisites

You need an active Slack session in your browser. Log into your workspace at app.slack.com in Chrome, Chromium, Edge, or Firefox before running setup.

Install

Claude Code

claude mcp add slack-mcp -- npx -y @aaronsb/slack-mcp

Then ask Claude to run the auth tool. It will guide you through browser selection, profile selection, and automatic token extraction.

Claude Desktop

Download the .mcpb file for your platform from the latest release:

Platform	File
macOS (Apple Silicon)	`slack-mcp-darwin-arm64.mcpb`
macOS (Intel)	`slack-mcp-darwin-x64.mcpb`
Linux (x64)	`slack-mcp-linux-x64.mcpb`
Linux (ARM)	`slack-mcp-linux-arm64.mcpb`
Windows (x64)	`slack-mcp-windows-x64.mcpb`

Open the file (double-click or drag into Claude Desktop). When prompted for tokens, you can either:

Leave them blank and use the auth tool after connecting
Paste tokens if you already have them

Standalone binary

Download the binary for your platform from releases, then:

# Extract tokens from your browser (interactive)

./slack-mcp setup

Run as MCP server (stdio, default)

./slack-mcp

Run as MCP server (SSE, for remote/shared access)

./slack-mcp --transport sse

npm (global)

npm install -g @aaronsb/slack-mcp

slack-mcp setup

Token setup

There are three ways to get your Slack tokens, from easiest to most manual:

Automatic (Chrome/Edge)

The auth MCP tool or slack-mcp setup CLI command will:

Detect your installed browsers
Let you pick which browser and profile has Slack
Open the browser, navigate to Slack, and extract tokens via Chrome DevTools Protocol
Validate and save them

Requires Chrome to be fully closed before extraction — your tabs will restore when you reopen it.

Semi-automatic (Firefox)

The setup flow writes a temporary browser extension to a temp directory, then guides you to load it in Firefox via about:debugging. The extension extracts tokens and sends them to the local callback server. It's removed automatically when Firefox closes.

Manual

Run slack-mcp setup or use the auth tool — if no browser is detected or automatic extraction fails, it falls back to a localhost web page with step-by-step DevTools instructions.

You can also set tokens directly via environment variables:

export SLACK_MCP_XOXC_TOKEN="xoxc-..."

export SLACK_MCP_XOXD_TOKEN="xoxd-..." ./slack-mcp

Settings come from the environment your MCP client config provides. A .env file in the working directory may set only SLACK_MCP_PERSONALITY and SLACK_MCP_NO_BROWSER, and never overrides a variable the environment already sets. If .env sets any other key the environment does not, the server refuses to start and names the key; set it in the client config instead.

Lifecycle

Over stdio the server exits cleanly when its client is gone: stdin closes, a termination signal arrives (SIGTERM, SIGINT, SIGHUP), or its parent process exits. Each exit flushes the caches and releases the ledger locks, so the next instance is not left read-only. On Windows, the npm wrapper's child.kill terminates the server forcibly, so this graceful shutdown does not run there.

Remote deployment (experimental)

Remote deployment is experimental and has not been tested against a real SSH session. Whether the server supports remote use at all, and in what form, is still open (see #102). Nothing below applies unless you set SLACK_MCP_DEPLOYMENT=remote.

A wedged connection, such as a half-open SSH session, leaves the pipe open with nobody reading it. Only an idle timeout catches that, and it is valid only where it can happen, so the server ties the timeout to how it is deployed:

Deployment	`SLACK_MCP_IDLE_TIMEOUT`
stdio, local	Not allowed. A stdio client does not respawn a server that exits, so an idle-but-healthy session would find it disconnected.
stdio, remote (over SSH)	Defaults to `2h`. Set a duration (`90m`) to change it, or `off` to disable.
SSE	Not allowed. Each session is cleaned up when its connection ends.

The deployment is local unless you declare it. The server does not detect it: SSH_CONNECTION only means some ancestor logged in over SSH (running claude in an SSH session, VS Code Remote-SSH), not that the MCP pipe crosses SSH. Only the MCP client config that launches the server knows, so declare remote there, in the entry that starts the server over SSH. ssh does not forward your environment, so pass the variable through the remote command line with env:

"mcpServers": { "slack": { "command": "ssh", "args": ["host", "env", "SLACK_MCP_DEPLOYMENT=remote", "slack-mcp"] } } }

(ssh joins the arguments into one remote command line, so this runs env SLACK_MCP_DEPLOYMENT=remote slack-mcp on the host. Setting it in the client's env block does not work, because that only reaches the local ssh process.) A timeout set where it is not allowed, or a value that does not parse, stops the server at startup with the reason on stderr.

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=` raw Slack search syntax (passed as written) plus resolved filters `in`, `from`, `after`, `before`, `has` (link, pin, :emoji:), `thread`; `scheduled=true` lists your pending scheduled messages, soonest first, and never your unsent composer drafts (ADR-016)
`estate`	noun	Workspace shape and relationships: `view='about'\	'families'\	'person'\	'initiatives'\	'convergence'\	'people'\	'channels'`;` about`/`person `take` render='graph' `to also write a static HTML graph page (not in` batch`)
`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 (a thread reply can also go to the channel with `broadcast=true`), files from the exchange directory (`files=['report.pdf']`, bare names, at most 10, shared as one message with `text` as the comment), or an emoji reaction; `at=` schedules a message for Slack to send later (2 minutes to 120 days; a time with no offset is read in your Slack profile zone and refused if this machine's zone disagrees) and `cancel=` withdraws one (ADR-016); scanned for secrets and gated before anything is sent or scheduled, with the send time part of what an approval covers (ADR-013)
`dismiss`	verb	Mark inbox items handled — private watermark, invisible to Slack
`mark-read`	verb	Fire read receipts — the one visibly-public read signal; refused at a quarantined destination, and never opens a DM
`auth`	verb	Interactive token setup (localhost only)
`download`	verb	Download a shared file into the exchange directory (`filename=` is a bare name, not a path; a taken name is saved as `name (n).ext` and the result says so)
`put`	verb	Write a new file into the exchange directory for `say files=` to attach, for clients whose file tools cannot reach the server's filesystem: `name=` (bare name) and exactly one of `content=` (text) or `base64=` (standard alphabet, padding optional); at most 5 MiB; never overwrites (a taken name is saved as `name (n).ext`), never reads, lists, or deletes (ADR-012)
`unlock`	verb	Open a local page in your browser to review and clear quarantines and the strike lock; the page clears, the tool returns no link and never reports what was cleared (ADR-013)

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.

Outbound safety

Everything this server posts is attributed to your account, and the agent reads text anyone in the workspace can write. So every say passes a fixed order before any content reaches Slack or any DM is opened (ADR-013):

Strike lock — after too many blocks, every say and mark-read is refused until you clear it (CLI, or the unlock page).
Exchange directory — file names are bare names inside it (ADR-012).
Quarantine — a destination a block closed refuses say and mark-read; reads keep working.
Secret scanner — the text as sent, a reaction's emoji, and each file's name and bytes, including base64, hex, URL-encoded, gzip, and zlib content. A match is a block: nothing is sent, and the agent is told the class and the field, never the value.
Approval gate — a destination outside your organization, or (in strict) a file download took from another conversation, waits for you as a pending request. Nothing is sent until you approve it.

Two settings in your MCP client config shape this (ADR-014); .env cannot set them:

Setting	Values	Default	Effect
`SLACK_MCP_IDENTITY`	`human`, `agent`	`human`	Whose account this is: the agent writes on your behalf, or as itself. Sets the `say` description, the server instructions, and the notice a block posts: "[automated] A message from this account was blocked by a safety filter." or "I can't share that."
`SLACK_MCP_SAFETY`	`strict`, `soft`	`strict`	`strict` quarantines on the first block and locks at two strikes. `soft` warns on the first, quarantines from the second, locks at three, and lets a downloaded file move between conversations with a warning.

A block posts the notice into the quarantined conversation, never to a destination outside your organization and never to a person with no DM. Blocks, pending requests, and sends trust let through are logged as outbound-safety: BLOCKED, PENDING, and TRUSTED lines (destination, IDs, class, counts; never content). When state needs you, inbox, messages, estate, and batch results open with a banner.

A block that cannot be written to the quarantine file holds every say and mark-read in that server process (in memory) and issues a lift request (lift=strikes). Fix the file, then approve the request or run

Only the beginning is shown; read the rest in the repo

Slack

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Chat & emaili

Common questions

Alternatives

Vexa

emailmd

MCP WhatsApp Cloud

README from the maker

Slack MCP

How it works

Prerequisites

Install

Claude Code

Claude Desktop

Standalone binary

Run as MCP server (stdio, default)

Run as MCP server (SSE, for remote/shared access)

npm (global)

Token setup

Automatic (Chrome/Edge)

Semi-automatic (Firefox)

Manual

Lifecycle

Remote deployment (experimental)

Tools

Outbound safety