Slack MCP limitations in private channels

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Where does the bug appear (feature/product)?

Cloud Agent (GitHub, Slack, Web, Linear)

Describe the Bug

Automations Slack MCP cannot read a private channel the Cursor bot is already in.

Please enable groups:history and groups:read on the Automations Slack token (not only Cloud Agents), and allow read_slack_messages / list_slack_channels for private channels the bot has joined when the run was triggered from that channel.

7

Hey @Mairead_McCabe

Quick unblock: this isn’t a permissions/scope issue (the Cursor Slack app already has those read scopes), so enabling groups:* won’t change anything. The fix is to remove the “Read Slack channels” action from the automation. With just your Slack message trigger on the private channel (and @Cursor a member), the run can read that private channel, including the thread.

  1. Go to cursor.com/automations and open the automation.
  2. Remove the Read Slack channels action (keep Send to Slack if you use it to reply).
  3. Post a real message in the channel that matches the trigger. The dashboard Test button won’t work here, since it doesn’t carry Slack trigger context.

Two notes: that run can only read the channel it was triggered from, and channel listing is public-only, so reference the channel by its ID rather than by name. Reading or listing other private channels isn’t supported today, by design.

What you’re running into with the action enabled isn’t intended behavior. We’ve let the team know and it’s an issue we’re tracking. Docs for reference: Automations. Let me know if step 3 still errors!