Slack Web API

This server does not support automatic client registration (no DCR or CIMD), so the MCP client cannot register itself. Create an OAuth app in the provider's developer settings, allow-list your MCP client's OAuth callback URL as a redirect URL, and give the client that app's client ID and secret. Then connect and approve access in the browser.

The Slack app must also have Slack MCP server access enabled (settings.is_mcp_enabled: true in the app manifest) — Slack rejects tokens from apps without it, and clients typically surface that as a generic connection failure.

Fastest path: create a pre-configured Slack app — the manifest pre-fills the MCP flag and all search:read.*, history, and write scopes; you add your client's callback URL under OAuth & Permissions after creation, then copy the client ID and secret from Basic Information.

Open App Management. Under Your App Configuration Tokens, click Generate Token to create an app configuration access token for Manifest API calls, as documented in Configuring apps with app manifests. Slack also issues a refresh token; config access tokens expire after 12 hours and can be rotated with tooling.tokens.rotate.