Jack Dorsey's Block launches Buzz, an open-source Slack rival built for teams of humans and AI agents

Block's Buzz Wants AI Agents in Your Work Channels, Not Bolted on as Bots

Jack Dorsey's Block has a new bet about what workplace chat should look like when some of your colleagues are not people.

On July 21, the company unveiled Buzz, a free, open-source group chat platform that places AI agents alongside human workers in the same conversations and folds GitHub project management into the same window 1. Twitter and Block co-founder Jack Dorsey announced the app on X, calling it "model-agnostic, decentralized, self-sovereign, and open source" and describing it as built to reduce Block's dependency on Slack and GitHub 1.

The architectural choice is the story. Slack and Microsoft Teams already host AI agents, but those agents arrive as apps or bots layered onto channels designed for human-to-human conversation. Buzz starts from a different premise: its channels are built for mixed teams of people and software 1.

That distinction reflects where work is heading. Companies that lean on AI agents for real tasks are finding that coordinating those agents across disconnected platforms creates friction 1. Buzz collapses chat, agent coordination, and project tracking into one workspace, removing a layer of context-switching that has become routine in AI-heavy workflows.

The open-source control play

Dorsey is not framing Buzz as a product you rent. The code is live on GitHub, and the desktop app is free for macOS, Windows, and Linux 1. Teams can self-host, modify the source code, and build features on their own schedule rather than waiting on a vendor roadmap.

For organizations wary of routing proprietary conversations and agent activity through a third-party SaaS layer, self-hosting offers a governance lever that Slack and Teams do not easily match. Paradigm partner and CTO Georgios Konstantopoulos, who recently unveiled Centaur, a similar open-source product that runs inside Slack or through an API, made the enterprise case directly: in the enterprise setting, you want to "self-host for security and control" 1. Konstantopoulos described Centaur as a "virtual employee" and pitched it as a productivity multiplier for teams 1.

Two different builders converging on the same concept in the same window of time is itself telling. The market is probing whether AI-native collaboration needs its own infrastructure rather than plugins inside incumbents.

What changes when agents are peers

If a team genuinely treats AI agents as first-class participants in shared channels, the implications stretch beyond convenience. Code reviews, status updates, and decisions that currently pass through human-only workflows could involve agents contributing directly to the thread. Accountability gets harder to map: when an agent proposes a change that ships, who signs off? The tool architecture does not answer that question. It does create the conditions where the question has to be asked.

Buzz is candid about its readiness. The platform admits it is in its early stages and that teams should not migrate over yet 1. Block, which also operates Square, Cash App, Afterpay, and Tidal, appears to be treating Buzz as a foundation to build on rather than a finished product 1.

The competitive picture

Buzz's most interesting rival may not be Slack. It is the assumption underlying Slack, Teams, and the entire category of workplace messaging built over the last decade: that the participants in a work conversation are, fundamentally, people. Dorsey is betting that assumption is expiring. Whether organizations are ready to restructure coordination, review, and accountability around non-human teammates is a separate question, and a harder one to answer.

For now, Buzz is a free download and an open codebase. The bet it represents is bigger than the software.