Block, the fintech company led by Jack Dorsey, released Buzz on July 21, launching a free, open-source workplace platform built for people and AI agents to collaborate inside the same conversation. The company describes it as a direct challenger to Slack and GitHub, aiming to replace the practice of switching between separate chat, project-management and code-hosting tools.

Built on a decentralized identity protocol

Rather than running solely on Block’s own servers, Buzz is built on Nostr, an open, decentralized protocol in which every identity is a cryptographic keypair and every action is signed. According to Block’s engineering team, that design lets a human “sign a narrowly scoped authorization” for an agent, while the agent then signs its own work with its own identity — so a bot’s actions stay traceable, and its access can be revoked without touching the human account that created it.

The same approach extends to code: Buzz stores git repositories as content-addressed, immutable packfiles designed to handle the high commit volume autonomous agents can generate, alongside chat channels, threads, direct messages, voice calls and automated workflows in one workspace.

Model-agnostic by design

Buzz works with any AI system that speaks the Agent Client Protocol, including Anthropic’s Claude Code, OpenAI’s Codex and the open-source agent goose — a contrast with collaboration tools tied to a single vendor’s models, such as Anthropic’s own Claude Cowork.

“Every company is going to need a place where humans and agents work together,” Bradley Axen, Block’s head of AI capabilities, said in the announcement. “The question is whether that place is proprietary or open.”

The free desktop app is available now for macOS, Windows 11 and Linux, either self-hosted from the project’s public code or run through Block’s hosted version. Block itself cautions that Buzz remains early-stage software, and teams with workflows already built around Slack and GitHub are unlikely to switch immediately.

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