Slack
FreemiumThe team chat that every tool and every agent can post into; channels as the audit log of a company.
What it is
Slack is the default internal chat for companies: channels, threads, huddles, canvases and lists, plus the largest integration catalog in the category. Nearly every tool in this catalog can post to a Slack channel (Linear, GitHub, Stripe, Cloudflare, analytics alerts), and the platform supports bots, slash commands, workflows without code, and apps with interactive messages. Recent versions add AI summaries and search across channels, and the major coding agents (Claude Code among them) can be started from a Slack thread and report back there.
The free plan keeps a limited history window; paid plans are per seat and unlock full history, unlimited apps and admin controls.
Where it fits in the AI OS
Work OS, the shared inbox of the team. In an agent-operated company the useful pattern is one channel per system ("#deploys", "#billing", "#content-queue") where agents post what they did and humans reply to correct them; the channel becomes the audit trail. Because Slack is where people already are, it is also the lowest-friction place to trigger an agent.
Insider notes
membersHow Serge's stack uses it
The membership project's team channel is not documented in the public notes; the site itself uses its own feed as the community and Telegram as the bonus channel rather than Slack.
[SERGE: fill in]
Setup in 5 minutes
- Create a workspace and three channels:
#general,#deploys,#alerts. - Add the GitHub app and subscribe
#deploysto your repo's pull requests and deployments (/github subscribe owner/repo). - Create an incoming webhook for
#alerts; from a Worker,POSTa JSON{ "text": "..." }on error. - Add the Linear app so issue links unfurl and status changes post.
- Install the Claude app for Slack if you want to kick off Claude Code tasks from a thread.
Alternatives
- Discord — free unlimited history, better for communities than for companies.
- Microsoft Teams — if the company already lives in Microsoft 365.
- Telegram groups — free, fast, weaker integrations; used as the member channel in this stack.
- Zulip / Mattermost / Rocket.Chat — open-source, self-hosted.