> ## Documentation Index
> Fetch the complete documentation index at: https://docs.custral.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Slack

> Bring Slack messages into Custral as conversations and reply back from the inbox.

## What it does

The Slack integration has three halves:

1. **Outbound**. Custral posts messages into Slack channels for workflow notifications ("a new high-priority Conversation just landed", "Deal X moved to Closed-Won").
2. **Inbound conversations**. Messages in linked Slack channels flow into Custral as conversations. Agents reply from the Custral inbox; their replies post back to the Slack thread as the bot user.
3. **Ask Custral**. Mention `@Custral` in a linked channel and the assistant answers in the thread, using your workspace's own records, conversations and tasks.

## Connect

<Steps>
  <Step title="Authorize in Custral">
    **Settings → Channels → Add Channel → Slack**. Sign in to your Slack workspace and grant the requested scopes (read history, post messages, read users' email and reactions).
  </Step>

  <Step title="Link a channel">
    Pick a public or private Slack channel from the dropdown. Custral's bot will be auto-joined to public channels; for private channels, invite the bot manually.
  </Step>

  <Step title="Choose a promotion policy">
    Decide how new top-level Slack messages become Custral conversations:

    * **Manual**: only when a teammate reacts with the trigger emoji (the ticket emoji by default).
    * **Matching records**: auto-promote when the sender's Slack-profile email matches an existing contact.
    * **Auto**: every top-level message starts a conversation.
  </Step>
</Steps>

## How threading works

A Slack thread maps one-to-one with a Custral conversation. The first top-level message that passes the promotion policy creates the conversation; replies in that thread append to the same conversation, so each thread stays a single, consistent conversation in Custral.

## Replying from Custral

When an agent replies on a Slack conversation in Custral, the message is posted back to the linked Slack channel in the same thread. The Custral bot is the author, and the agent's name is appended in italics so customers see who wrote it.

## Ask Custral in Slack

Mention `@Custral` in any linked channel and the assistant replies in that thread:

```
@Custral what's the status of the Northwind deal?
```

It answers from your workspace: records, conversations, tasks, objects and documents.

<Note>
  **It only reads.** The assistant cannot create, edit or delete anything from Slack. Slack has no way to show you an approval prompt, so write access is deliberately not available there. Use the in-app assistant (⌘I) for anything that changes data.
</Note>

**Who gets an answer.** Only people with a Custral account in this workspace. Custral matches your Slack profile email to your Custral account, and the assistant runs with your own permissions, so it can never show a teammate something they could not already open. Anyone else, including single-channel guests and Slack Connect users from another company, gets a short note explaining why rather than an answer.

**Turning it off.** Per channel, under **Settings → Channels → \[your Slack channel] → Slack settings**. Channels linked before this feature existed answer mentions by default.

### Requirements

Asking in Slack needs the `app_mentions:read` scope, which was added after the first release. If mentions do nothing, re-authorize from **Settings → Channels → Add Channel → Slack**. Custral shows a banner there listing any scopes your workspace is missing.

## Configuration

Per linked channel (**Settings → Channels → \[your Slack channel] → Slack Settings**):

| Setting          | Description                                                                     |
| ---------------- | ------------------------------------------------------------------------------- |
| Promotion policy | **Manual**, **Matching records**, or **Auto**.                                  |
| Trigger emoji    | The reaction that force-promotes a Slack message (the ticket emoji by default). |
| Answer @mentions | Whether `@Custral` is answered in this channel. On by default.                  |

## Limitations (MVP)

* **No Slack Connect / shared channels**: only channels in your own workspace.
* **No file attachments**: text only.
* **No edit / delete sync**: only the original message text is recorded.
* **One reaction**: only the configured trigger emoji is honored. Other reactions are ignored.
* **Mentions do not remember the thread**: each `@Custral` is answered on its own. Follow-up questions need the context repeating.
* **Mentions cannot change anything**: the assistant reads only. See "Ask Custral in Slack" above.

## Troubleshooting

| Symptom                                               | Fix                                                                                                                                                                           |
| ----------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| "Not in channel" error when sending                   | Invite the Custral bot to the target Slack channel.                                                                                                                           |
| Messages not appearing in Custral                     | Check the channel's promotion policy, **Manual** requires the trigger emoji.                                                                                                  |
| "Invalid authentication" error                        | Access was revoked. Re-authorize from **Settings → Channels → Slack**.                                                                                                        |
| New messages stopped flowing in                       | The connection may have lost authorization, re-authorize the Slack channel.                                                                                                   |
| `@Custral` does nothing                               | Three things to check, in order: the channel is linked in Custral, "Answer @mentions" is on for it, and your workspace has re-authorized since `app_mentions:read` was added. |
| "I can only answer for people with a Custral account" | Your Slack profile email does not match a Custral account in this workspace. Check the email on your Custral profile.                                                         |

## Disconnect

Removing a Slack channel from Custral has the bot leave the corresponding Slack channel so events stop flowing. Re-linking creates a fresh channel; conversation history from the previous link remains intact.


## Related topics

- [External](/data/properties/complex/external.md)
- [Integrations](/integrations/overview.md)
- [MCP Connections](/ai/mcp-connections.md)
- [Learn the Product](/start/onboarding/learn.md)
- [conversation.assigned](/dev/webhooks/events/conversation-assigned.md)