Slack MCP server

Endpoint: https://mcp.slack.com/mcp · Authentication: Sign in with OAuth

Remote MCP server for Slack messages, channels, users, canvases, and collaboration context.

Test it live Run the release-readiness report

How do I authenticate?

Add the endpoint in your client, start Connect or Sign in, approve the requested scopes, and return to the client. OAuth discovery finds the authorization server; client registration requirements vary by provider. Follow the provider guidance and client setup below.

Authentication and connection guide

Connection specification

Remote endpoint: https://mcp.slack.com/mcp
Browser access: Not yet measured
Declared MCP transport: Streamable HTTP
Live-validated MCP transport: Not yet verified — Latest validation did not verify a transport
Declared authentication: OAuth 2.1
Detected authentication: OAuth 2.1 detected or retained from publisher evidence
Protocol lifecycle: Not yet negotiated
Authorization server: https://mcp.slack.com
Category: Communication

Product documentation · Official listing documentation

Provider guidance

Browser OAuth requires the mcptest operator's SLACK_OAUTH_CLIENT_ID and SLACK_OAUTH_CLIENT_SECRET Worker bindings. Production readiness must not be claimed until both are configured.

More Communication MCP servers · Browse all MCP servers · Test this endpoint in the MCP Playground

Authorization setup

mcptest operator setup required

This provider requires a confidential application managed by the mcptest operator. Its client secret and token exchange stay server-side and must never be pasted into a browser.

Publisher evidence reviewed 2026-08-24.

Client ID: Required
Client secret: Required — never enter it in a browser
Browser/public client: Not supported

Required non-secret settings

Application owner: mcptest operator (required)
Distribution: Internal workspace or published app as applicable (required)

Callback URIs

https://mcptest.io/oauth/callback

Provider setup steps

The mcptest operator creates and owns the Slack application.
Configure the app for the workspace or published distribution required by Slack.
Register the exact hosted mcptest callback URI.
Store the client ID and client secret only in operator-controlled server bindings.

Open provider setup or application page

Publisher documentation

Connect it

Live-validated endpoint: https://mcp.slack.com/mcp · Streamable HTTP. mcptest operator setup required: This provider requires a confidential application managed by the mcptest operator. Its client secret and token exchange stay server-side and must never be pasted into a browser.

Agent prompt for Claude Code or Codex

Add the Slack MCP server to my MCP client configuration and verify that it works.

What it is: Remote MCP server for Slack messages, channels, users, canvases, and collaboration context.
Server URL: https://mcp.slack.com/mcp
Transport: Streamable HTTP (remote MCP server, no local install).
Authentication: OAuth 2.1. mcptest operator setup required: This provider requires a confidential application managed by the mcptest operator. Its client secret and token exchange stay server-side and must never be pasted into a browser.
Tools: not yet observed by mcptest; tools/list will show them.
Reference: https://mcptest.io/servers/slack/

Steps:
1. Work out which MCP client I use (Claude Code, Codex, Cursor, VS Code or another) and add the server under the name "slack" in that client's MCP configuration, user scope unless I ask otherwise.
   Claude Code: claude mcp add --transport http --scope user 'slack' 'https://mcp.slack.com/mcp'
   Codex: codex mcp add 'slack' --url 'https://mcp.slack.com/mcp'
   Other clients: use the setup for that client on the reference page.
2. Never write a credential value into a file that could be committed; reference an environment variable or the client's secret store, and ask me for any value you need.
3. Verify: connect to the server and call tools/list. Confirm the tools above are listed, and report any sign-in step I still have to complete.

Claude Code setup

Run in a terminal. This user-scoped entry is available across projects.

claude mcp add --transport http --scope user 'slack' 'https://mcp.slack.com/mcp'

Codex CLI setup

Run in a terminal; Codex stores the entry in ~/.codex/config.toml.

codex mcp add 'slack' --url 'https://mcp.slack.com/mcp'

Cursor setup

Add to .cursor/mcp.json for this project, or ~/.cursor/mcp.json for all projects.

{
  "mcpServers": {
    "slack": {
      "url": "https://mcp.slack.com/mcp"
    }
  }
}

VS Code setup

Add to .vscode/mcp.json, or run “MCP: Open User Configuration” for a private user-level entry.

{
  "servers": {
    "slack": {
      "type": "http",
      "url": "https://mcp.slack.com/mcp"
    }
  }
}

Claude setup

Add the endpoint above in Claude:

Customize > Connectors > Add custom connector
Team/Enterprise: Organization settings > Connectors > Add > Custom > Web

Claude Desktop setup

Add the endpoint above in Claude Desktop:

Remote: Customize > Connectors (same as claude.ai)
Local: Settings > Developer > Edit Config, or Settings > Extensions for .mcpb files
~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows), local servers only

ChatGPT setup

Add the endpoint above in ChatGPT:

ChatGPT web: Plugins > Add custom MCP server, then configure authentication and accept the risk warning

Windsurf setup

Add the endpoint above in Windsurf:

~/.config/devin/mcp_config.json (%APPDATA%\devin\mcp_config.json on Windows), serverUrl or url
Cascade panel > ... > MCPs > Open MCP config file

Gemini CLI setup

Add the endpoint above in Gemini CLI:

gemini mcp add --transport http <name> <url>
~/.gemini/settings.json (user) or .gemini/settings.json (project), mcpServers

MCP SDK setup

Add the endpoint above in MCP SDK:

Programmatic: new Client(...).connect(new StreamableHTTPClientTransport(url))

Notes for every client

Provider setup: The mcptest operator creates and owns the Slack application.
Provider setup: Configure the app for the workspace or published distribution required by Slack.
Provider setup: Register the exact hosted mcptest callback URI.
Provider setup: Store the client ID and client secret only in operator-controlled server bindings.
Publisher evidence (reviewed 2026-08-24): https://docs.slack.dev/ai/slack-mcp-server/
Provider guidance: Browser OAuth requires the mcptest operator's SLACK_OAUTH_CLIENT_ID and SLACK_OAUTH_CLIENT_SECRET Worker bindings. Production readiness must not be claimed until both are configured.

Client compatibility

Client	Status	Why
Claude Code	Supported	Claude Code supports Streamable HTTP servers and OAuth sign-in.
Codex	Supported	Codex supports Streamable HTTP servers and OAuth sign-in.
Cursor	Supported	Cursor supports Streamable HTTP servers and OAuth sign-in.
VS Code	Supported	VS Code supports Streamable HTTP servers and OAuth sign-in.
Claude	Supported	Claude supports Streamable HTTP servers and OAuth sign-in.
Claude Desktop	Supported	Claude Desktop supports Streamable HTTP servers and OAuth sign-in.
ChatGPT	Supported	ChatGPT supports Streamable HTTP servers and OAuth sign-in.
Windsurf	Partial	Windsurf's documentation does not state support for OAuth sign-in.
Gemini CLI	Supported	Gemini CLI supports Streamable HTTP servers and OAuth sign-in.
MCP SDK	Supported	MCP SDK supports Streamable HTTP servers and OAuth sign-in.

Computed from this server's validated transport, protocol and authentication against documented client support. Checks the catalog has not observed are not counted.

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Guides for this server

Watch this server for breaking changes

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   :alt: Tested on mcptest.io
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Latest validation evidence

Validation status: Online when last tested
Validation checked at: Oct 26, 2026 at 2:08 PM
Validation detail: Authentication challenge at https://mcp.slack.com/mcp returned HTTP 401; endpoint was reachable but did not complete an MCP probe; authentication oauth

Tool inventory

Requires authorization; inventory not observed

The catalog validator lists tools only on servers that answer without credentials. Slack asks for OAuth 2.1 sign-in first, so its tools, resources and prompts were not observed. Connect in the Playground with your own credentials to list them.