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

# Slack Reference

> Interface parameters, endpoints, and event handling for the Slack interface.

## Interface Parameters

Pass one of `agent`, `team`, or `workflow` to the `Slack` constructor.

```python theme={null}
from agno.os.interfaces.slack import Slack

Slack(agent=my_agent, streaming=True, prefix="/slack")
```

| Parameter                | Type                             | Default         | Description                                                                                                                                                                                                                |
| ------------------------ | -------------------------------- | --------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `agent`                  | `Optional[Agent]`                | `None`          | Agno `Agent` instance.                                                                                                                                                                                                     |
| `team`                   | `Optional[Team]`                 | `None`          | Agno `Team` instance.                                                                                                                                                                                                      |
| `workflow`               | `Optional[Workflow]`             | `None`          | Agno `Workflow` instance.                                                                                                                                                                                                  |
| `prefix`                 | `str`                            | `"/slack"`      | URL prefix for Slack endpoints (e.g., `/slack` means events arrive at `/slack/events`).                                                                                                                                    |
| `tags`                   | `Optional[List[str]]`            | `None`          | FastAPI route tags for API documentation. Defaults to `["Slack"]`.                                                                                                                                                         |
| `reply_to_mentions_only` | `bool`                           | `True`          | When `True` (default), the bot responds to @mentions in channels and all DMs. When `False`, responds to all channel messages.                                                                                              |
| `token`                  | `Optional[str]`                  | `None`          | Bot token. Falls back to `SLACK_TOKEN` environment variable.                                                                                                                                                               |
| `signing_secret`         | `Optional[str]`                  | `None`          | Slack app signing secret. Falls back to `SLACK_SIGNING_SECRET` environment variable.                                                                                                                                       |
| `streaming`              | `bool`                           | `True`          | Enable real-time streaming with task cards and live text updates.                                                                                                                                                          |
| `loading_messages`       | `Optional[List[str]]`            | `None`          | Status messages shown while the agent processes. Rotated automatically by Slack.                                                                                                                                           |
| `task_display_mode`      | `str`                            | `"plan"`        | How task cards render in the streaming UI. `"plan"` shows a collapsible plan block.                                                                                                                                        |
| `loading_text`           | `str`                            | `"Thinking..."` | Status text shown while the agent starts processing.                                                                                                                                                                       |
| `suggested_prompts`      | `Optional[List[Dict[str, str]]]` | `None`          | Prompts shown when a user opens a new thread. Each dict has `title` and `message` keys. Defaults to Help and Search prompts.                                                                                               |
| `ssl`                    | `Optional[SSLContext]`           | `None`          | SSL context for the Slack WebClient.                                                                                                                                                                                       |
| `buffer_size`            | `int`                            | `100`           | Characters to buffer before flushing a streaming update.                                                                                                                                                                   |
| `max_file_size`          | `int`                            | `1073741824`    | Maximum file size in bytes for uploads and downloads (default 1 GB).                                                                                                                                                       |
| `resolve_user_identity`  | `bool`                           | `False`         | Look up each user's email and display name via the Slack `users.info` API. When enabled, the agent receives the user's email as `user_id` instead of their Slack ID, and `metadata` includes `user_name` and `user_email`. |

## Endpoints

Available at the `/slack` prefix (customizable with `prefix`).

### `POST {prefix}/events`

Receives all Slack events (URL verification, messages, app mentions, thread starts).

| Status  | Description                                                                                         |
| ------- | --------------------------------------------------------------------------------------------------- |
| **200** | Event acknowledged. Processing happens in the background so Slack gets a response within 3 seconds. |
| **400** | Missing `X-Slack-Request-Timestamp` or `X-Slack-Signature` headers.                                 |
| **403** | Invalid Slack signing signature.                                                                    |
| **500** | `SLACK_SIGNING_SECRET` is not set (checked on each request, not at startup).                        |

### Built-in Event Handling

| Event                      | Behavior                                                                                                                                |
| -------------------------- | --------------------------------------------------------------------------------------------------------------------------------------- |
| URL verification           | Echoes the `challenge` field back to Slack during app setup.                                                                            |
| `assistant_thread_started` | Sets `suggested_prompts` on new threads (streaming mode only).                                                                          |
| Retry deduplication        | Events with `X-Slack-Retry-Num` are acknowledged without reprocessing. The original event is already being processed in the background. |
| Bot self-loop prevention   | Events with `bot_id` or subtypes `bot_message`, `message_changed`, `message_deleted`, and other bot lifecycle events are ignored.       |

## Developer Resources

<CardGroup cols={2}>
  <Card title="Slack Guide" icon="book" href="/agent-os/interfaces/slack/introduction">
    Setup, code examples, streaming behavior, and troubleshooting.
  </Card>

  <Card title="SlackTools Reference" icon="wrench" href="/tools/toolkits/social/slack">
    Toolkit parameters and methods for sending messages, searching, and file management.
  </Card>
</CardGroup>