Slack

Host agents as Slack Applications.

Use the Slack interface to serve Agents, Teams, or Workflows on Slack. It mounts Slack event routes on a FastAPI app and sends responses back to Slack threads.

Setup Steps

Follow the Slack setup guide in the cookbook.

Required configuration:

• SLACK_TOKEN (Bot User OAuth Token)
• SLACK_SIGNING_SECRET (App Signing Secret)
• An ngrok tunnel (for local development) and event subscriptions pointing to /slack/events

Example Usage

Create an agent, expose it with the Slack interface, and serve via AgentOS:

basic.py

from agno.agent import Agent
from agno.models.openai import OpenAIResponses
from agno.os import AgentOS
from agno.os.interfaces.slack import Slack

basic_agent = Agent(
    name="Basic Agent",
    model=OpenAIResponses(id="gpt-5.2"), # Ensure OPENAI_API_KEY is set
    add_history_to_context=True,
    num_history_runs=3,
    add_datetime_to_context=True,
)

agent_os = AgentOS(
    agents=[basic_agent],
    interfaces=[Slack(agent=basic_agent)],
)
app = agent_os.get_app()

if __name__ == "__main__":
    agent_os.serve(app="basic:app", port=8000, reload=True)

A complete example is available at cookbook/05_agent_os/interfaces/slack/basic.py.

Core Components

• Slack (interface): Wraps an Agno Agent, Team, or Workflow for Slack integration via FastAPI.
• AgentOS.serve: Serves the FastAPI app using Uvicorn.

Slack Interface

Main entry point for Agno Slack applications.

Initialization Parameters

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"	Custom FastAPI route prefix for the Slack interface.
tags	Optional[List[str]]	None	FastAPI route tags for API documentation. Defaults to ["Slack"] if not provided.
reply_to_mentions_only	bool	True	When True, respond to @mentions in channels and all direct messages. When False, respond to all channel messages too.
token	Optional[str]	None	Slack Bot User OAuth Token (xoxb-...). If omitted, the interface reads from environment configuration.
signing_secret	Optional[str]	None	Slack signing secret used to verify request signatures.
streaming	bool	True	Enable Slack chat_stream responses and event-driven streaming updates.
loading_messages	Optional[List[str]]	None	Optional rotating loading messages shown while processing streamed runs.
task_display_mode	str	"plan"	Task card display mode used by Slack streaming UI.
loading_text	str	"Thinking..."	Thread status text shown before streamed output starts.
suggested_prompts	Optional[List[Dict[str, str]]]	None	Suggested prompts sent when Slack starts an assistant thread.
ssl	Optional[SSLContext]	None	Custom SSL context for Slack SDK HTTP requests.
buffer_size	int	100	Stream buffer size for Slack chat_stream.
max_file_size	int	1073741824	Maximum uploaded/downloaded file size in bytes (default 1 GB).

Provide agent, team, or workflow.

Use different prefix, token, and signing_secret values when mounting multiple Slack interface instances on one FastAPI app.

Key Method

Method	Parameters	Return Type	Description
get_router	None	APIRouter	Returns the FastAPI router and attaches endpoints.

Endpoints

Mounted under the /slack prefix:

POST /slack/events

• Handles all Slack events (URL verification, messages, app mentions)
• Verifies Slack signature on each request
• Uses thread timestamps as session IDs for per-thread context
• Streams responses back into the originating thread (splits long messages)

Testing the Integration

1. Run the app locally: python <my-app>.py (ensure ngrok is running)
2. Invite the bot to a channel: /invite @YourAppName
3. Mention the bot in a channel: @YourAppName hello
4. Open a DM with the bot and send a message

Troubleshooting

• Verify SLACK_TOKEN and SLACK_SIGNING_SECRET are set
• Confirm the bot is installed and invited to the channel
• Check ngrok URL and event subscription path (/slack/events)
• Review application logs for signature failures or permission errors