Slack

Slack

This connector works in one Slack workspace through the Slack Web API (https://slack.com/api): list channels and people, read channel history and threads, post messages and replies, and add reactions. It authenticates with a token from a Slack app that you create and install in your own workspace (about 5 minutes).

Setup

1. Open https://api.slack.com/apps → Create New App → From a manifest → pick the workspace.
2. Paste this manifest (JSON) and click Create:

{
  "display_information": {
    "name": "AnythingMCP"
  },
  "features": {
    "bot_user": {
      "display_name": "AnythingMCP",
      "always_online": false
    }
  },
  "oauth_config": {
    "scopes": {
      "bot": [
        "channels:read",
        "channels:history",
        "channels:join",
        "groups:read",
        "groups:history",
        "im:read",
        "im:history",
        "mpim:read",
        "mpim:history",
        "chat:write",
        "reactions:write",
        "users:read"
      ]
    }
  },
  "settings": {
    "org_deploy_enabled": false,
    "socket_mode_enabled": false,
    "token_rotation_enabled": false
  }
}

3. Install App → Install to Workspace and allow. If the workspace only lets admins install apps, Slack sends an approval request to a workspace admin instead.
4. OAuth & Permissions → Bot User OAuth Token (starts with xoxb-): paste it into SLACK_TOKEN and install the connector.
5. Keep token rotation off (as in the manifest): with rotation on, the token expires every 12 hours and a pasted token stops working.

Bot token or user token

• A bot token (xoxb-, the default) acts as the app: messages are posted by "AnythingMCP", and it reads the history of a channel only once the app is a member. Public channels: slack_join_channel, or /invite @AnythingMCP in the channel. Private channels, group DMs: invite the app with /invite @AnythingMCP.
• A user token (xoxp-) acts as the person who installed the app: it sees every conversation that person sees and posts in their name. To get one, add the same scopes plus search:read under oauth_config.scopes.user in the manifest (App Manifest page), reinstall, and paste the User OAuth Token instead. Only a user token can search, so slack_search_messages is installed switched off: turn it on when you use a user token.
• Add users:read.email to the scopes if the AI should see people's email addresses.

Conversations and ids: every call takes ids, not names: channel ids start with C (public), G (some private), D (direct messages); user ids with U or W. Look them up with slack_list_conversations and slack_list_users. types chooses what is listed: public_channel (default), private_channel, mpim (group DMs), im (direct messages), comma-separated.

Messages, threads and timestamps: a message is identified by its channel and its ts (e.g. 1712345678.123456), which is also its time in Unix seconds. A reply to a thread has thread_ts set to the parent's ts; slack_get_thread_replies with the parent's ts returns the parent followed by the replies, and slack_post_message with thread_ts replies in the thread. oldest and latest bound the history in Unix seconds. Messages use Slack mrkdwn (*bold*, _italic_, <https://example.com|link text>, <@U123> to mention someone); text should stay under 4,000 characters.

Pagination: lists return response_metadata.next_cursor; pass it as cursor with the same other arguments while it is not empty. has_more says whether more history exists. Search pages with page (see messages.paging).

Rate limits: per method and per workspace. conversations.list and users.list allow about 20 calls a minute, conversations.history and conversations.replies about 50 a minute for an app installed in your own workspace, chat.postMessage about one message per second per channel. Over a limit Slack answers HTTP 429 with a Retry-After header.

Errors: Slack answers HTTP 200 with "ok": false and an error code; the connector reports these as errors.

• invalid_auth, not_authed, token_revoked, token_expired, account_inactive: the token is wrong, was revoked, or the app was uninstalled. Paste a fresh token.
• missing_scope (the needed field names the scope): add the scope to the app, reinstall it, and paste the new token if it changed.
• not_in_channel: the app is not a member of the channel; join it or invite the app.
• channel_not_found: a wrong id, or a private conversation the token cannot see.
• not_allowed_token_type: the method needs the other kind of token (search needs a user token).
• is_archived, msg_too_long, no_text, already_reacted, invalid_name (emoji names go without colons): fix the input.

Out of scope here: editing or deleting messages, files, channel management beyond joining, user groups, Slack Connect administration and Enterprise Grid org-wide installs.