Slack Summarizer - Composio

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This cookbook builds a standalone Python script that connects to a Slack workspace, fetches recent messages from a channel, and summarizes the key topics, decisions, and action items. We'll use scoped sessions to limit the agent to Slack tools only.

Prerequisites

Project setup

Create a new project and install dependencies:

bash

mkdir composio-slack-summarizer && cd composio-slack-summarizer
uv init && uv add composio composio-openai-agents openai-agents

Add your API keys to a .env file:

bash

COMPOSIO_API_KEY=your_composio_api_key
OPENAI_API_KEY=your_openai_api_key

Setting up the client

Composio takes an OpenAIAgentsProvider so that tools come back in the format the OpenAI Agents SDK expects.

<include>../../examples/slack-summariser/main.py#setup</include>

Connecting to Slack

Before summarizing, we need to make sure the user has connected their Slack workspace. The connect function creates a scoped session with toolkits=["slack"] and checks the connection status via session.toolkits(). If Slack is not connected, session.authorize("slack") starts the OAuth flow and returns a URL for the user to visit. wait_for_connection() blocks until they complete it.

<include>../../examples/slack-summariser/main.py#connect</include>

Summarizing a channel

With Slack connected, the summarize function creates a session and grabs the tools. We hand them to an agent with focused summarization instructions. Runner.run_sync handles the agentic loop: the agent calls the Slack tool to fetch messages and produces a summary.

<include>../../examples/slack-summariser/main.py#summarize</include>

Complete script

Here is everything together:

<include>../../examples/slack-summariser/main.py</include>

Running the script

First, connect your Slack workspace:

bash

uv run --env-file .env python main.py connect default

If Slack is not connected yet, you'll get an OAuth URL. Open it in your browser and authorize the app. If you've already connected, the script will print "Slack is already connected."

Then run the summarizer:

bash

uv run --env-file .env python main.py summarize default general

Replace general with any channel name you want to summarize.

Take it further

The summarizer reads from one channel, but the same pattern scales to broader workflows:

Cross-channel digest: summarize multiple channels in one run and post a combined digest to a #daily-summary channel
Trigger-based: use a Slack trigger to auto-summarize whenever a channel hits 50+ unread messages
Action items to Linear: add the Linear toolkit and have the agent extract action items from the summary and create tickets