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.

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

Slack Guide

Setup, code examples, streaming behavior, and troubleshooting.

SlackTools Reference

Toolkit parameters and methods for sending messages, searching, and file management.