Jack Dorsey’s payments company Block fired a shot across the enterprise-software industry on Tuesday when it publicly launched Buzz, a free, open-source workspace that gives AI agents the same cryptographic standing as the humans they work alongside. Instead of tagging a bot in a command queue, a team using Buzz can give an AI agent its own keypair identity, let it submit code patches and run approved workflows, and trace every action it takes back to the human who authorized it — a chain of accountability that current Slack bolt-on agents cannot provide.
The launch, announced by Dorsey on X at 12:33 ET on July 21, positions Buzz as a direct replacement for both Slack and GitHub inside Block (NYSE: XYZ) — the payments firm behind Square, Cash App, Afterpay, and Tidal. “We’re launching BUZZ! a new groupchat platform for teams of people and agents of all sizes, built to reduce our dependency on slack and github. Model-agnostic, decentralized, self-sovereign, and open source,” Dorsey wrote. Version 0.4.21 shipped the same day as a free desktop download for macOS, Windows, and Linux under an Apache 2.0 license.
The timing is deliberate. Enterprise teams are deploying AI coding agents at scale — 57% of organizations surveyed by LangChain already have agents in production — and the tooling designed for human-only teams is straining to keep up. Buzz is Block’s answer to that strain, rebuilt from the protocol layer up rather than bolted onto an existing platform.
What Buzz Does That Slack Cannot
Every participant in Buzz — human or AI agent — holds a secp256k1 keypair, the same elliptic-curve cryptography that underpins Bitcoin. Humans get one keypair. Agents get one keypair of their own, plus a second cryptographic signature that ties them back to their human owner. That pairing creates what the company calls a verifiable chain of custody: when an AI agent merges a pull request, posts a message, or triggers a workflow, the signed record shows not only that the agent acted, but which human authorized the agent to act.
This is more than an audit feature. Research by the Cloud Security Alliance found that 68% of organizations cannot clearly distinguish between human and AI agent activity in their systems, and that existing containment relies on disabling identities or shutting down compute environments — not on any built-in kill switch. Buzz’s identity model addresses that governance gap at the infrastructure level, not the policy level: the signed chain makes authorization legible and reversible in ways that session-token-based integrations in Slack cannot match.
In practice, those agents can open repositories, submit and review code, run workflows, edit shared canvases, orchestrate other agents, and drop into voice huddles. They use the same channels, threads, and direct messages as human teammates. The workspace ships with pre-built harnesses for three coding agents — Goose (Block’s own open-source framework), OpenAI’s Codex, and Anthropic’s Claude Code — connected through the Agent Client Protocol (ACP), an open standard for wiring agents into developer tools.
Built on Nostr: What Decentralized Actually Means Here
Buzz runs on Nostr — short for “Notes and Other Stuff Transmitted by Relays” — an open protocol first written in March 2020 by a pseudonymous developer and widely adopted for censorship-resistant social apps from 2022 onward. Dorsey has backed Nostr financially for years, and Buzz is the first time the protocol has powered an enterprise workspace product.
Every event in Nostr is a JSON object containing five fields: an id (a sha256 hash of the canonical content bytes), a pubkey (the sender’s secp256k1 public key), a kind (an integer that identifies the event type), tags (structured metadata), and a sig (a Schnorr signature over the canonical content). In Buzz, those events cover every action in the workspace — messages, reactions, code commits, CI results, review comments, workflow steps, and merge approvals — so the audit log is unified, searchable, and tamper-evident. Adding a new type of action to the system requires only a new kind integer, with no breaking changes to existing events.
One architectural nuance matters for anyone evaluating Buzz against fully distributed systems: it is not peer-to-peer. Each Buzz deployment runs on a single authoritative relay. “Decentralized” here means that any organization can run its own relay and retain full control of its data, relay configuration, and agents — not that there is no central relay within a given deployment. Block operates a hosted relay, currently free and without usage limits during beta. Organizations that prefer full infrastructure sovereignty can self-host: the stack requires Docker, Rust 1.88 or later, Node 24 or later, and pnpm.
The Buzz relay is written in Rust, with TypeScript and React clients. The multi-tenant isolation spec has been mechanized in TLA+ — a formal specification language for distributed systems — and its authorization properties have been verified in Tamarin, an automated security protocol prover. That level of formal verification is unusual for v0.4.21 software and reflects Block’s intention to build Buzz as infrastructure rather than a consumer product.
Git Hosting Inside the Workspace
Beyond chat, Buzz includes a built-in software forge using standard Git Smart HTTP, which means organizations can host repositories inside Buzz without a separate GitHub account. Feature branches become channels. Patches, CI results, review comments, and merge decisions are all stored as signed Nostr events alongside the human discussion that produced them, so the complete context for a code change lives in one indexed record rather than split across a chat tool and a code host.
Block’s own BuilderBot — an internal coding agent that handles more than 200,000 operations daily and accounts for roughly 15% of Block’s production code changes — has been operating inside Buzz during development, making Block the platform’s first and most visible reference customer. Goose, Block’s open-source agent framework released in January 2025, has accumulated more than 50,000 GitHub stars and now connects into Buzz as one of its three native harnesses.
Entering a Market Controlled by a Duopoly
Buzz’s ambitions collide with substantial incumbents. Estimated at approximately 47.2 million daily active users in 2025 based on third-party projections, Slack holds roughly 13% of the enterprise messaging market and commands nearly 80% Fortune 100 adoption through its Slack Connect product. Salesforce CEO Marc Benioff projected Slack-specific revenue of approximately $3 billion for fiscal 2026, and beginning this summer Slack is being automatically provisioned for all new Salesforce customers — an integration advantage that distribution alone cannot overcome overnight.
Microsoft Teams holds an estimated 37% share of the enterprise messaging market with 320 million monthly active users in 2026. Together, Teams and Slack form a duopoly that has proven durable against well-funded challengers for years.
Block itself is not in a position of financial strength to mount a prolonged commercial contest. The company reported a net loss of $308.7 million in Q1 2026, swinging from a $189.9 million profit in the same period a year earlier, driven by AI restructuring costs and a $172.8 million bitcoin remeasurement charge. A workforce reduction announced alongside Q4 2025 results cut headcount from 10,205 to under 6,000. Buzz enters the market as a free, Apache-licensed product whose commercial trajectory — if Block intends one — has not been announced. Bradley Axen, Block’s Head of AI Capabilities, told The New Stack that hosting a 10-person open-source project is cheap, while replacing enterprise-grade Slack would eventually need a different arrangement.
Who Else Is Building for the Agent Era
Buzz is not the only product chasing the same thesis. Georgios Konstantopoulos, partner and CTO at crypto venture firm Paradigm, unveiled Centaur on May 21, 2026, described as a “virtual employee” that runs either inside Slack or via an API. His argument on X after the Buzz launch: the near-term enterprise opportunity is embedding capable agents inside the platform teams already use, not asking them to replace it wholesale. “There’s a lot of room for improvement for agents that live in Slack and can do more work than just coding for teams,” Konstantopoulos wrote.
The two approaches reflect a genuine strategic fork. Centaur upgrades the incumbent. Buzz replaces it. Both are bets on the same underlying pressure: AI agents are no longer experimental additions to developer workflows, and the tooling built for human-only teams was not designed with agent governance in mind.
Block is also a member of the Linux Foundation’s Agentic AI Foundation, which it joined in December 2025 alongside Anthropic and OpenAI — and Buzz’s Agent Client Protocol is designed to remain compatible with the broader MCP ecosystem, which had crossed 9,400 public servers as of April 2026.
What It Cannot Do Yet
At version 0.4.21, Buzz is early-stage software that Block has published openly rather than polished into a commercial product. Mobile apps are unfinished. Push notifications are pending. Some workflow features lack complete execution paths. The self-hosted path requires engineering time: standing up a Nostr relay, managing Rust and Node version requirements, and integrating existing databases, codebases, or file systems — all before the first channel is created.
That onboarding overhead narrows Buzz’s immediate audience to software engineering teams already coordinating AI agents across a codebase and willing to invest in infrastructure they control. Solo operators, small businesses, and non-technical teams are not the intended users, and the platform does not pretend otherwise.
The open-source model also defers a question that every open-source enterprise tool eventually must answer: what pays for it? Block has said the hosted relay is free for beta. It has not said what comes after.
Cryptographic Identity and the Accountability Question
The most structurally novel aspect of Buzz is also the easiest to understate. Giving an AI agent its own keypair — and a second signature linking it to a human — is not just a bookkeeping feature. It is a primitive for accountability in a legal and organizational environment that does not yet have one.
Current enterprise AI integrations operate on delegation models that are difficult to audit: an agent runs under a service account, under an API key associated with a user, or under session credentials that expire and regenerate. When something goes wrong — a bad commit, an unauthorized API call, a workflow that spent money it was not supposed to spend — tracing responsibility through those layers is a forensic exercise. The signed event model in Buzz makes that trace automatic and tamper-evident from the moment of action.
As AI agent liability law develops — and 95% of executives surveyed by Writer in May 2026 said AI is changing roles and team structures at their organizations — the ability to answer “which human authorized this agent to do this, and when” may become a compliance requirement rather than a differentiator. Buzz builds that answer into its identity layer by default.
Whether that matters to a 2,000-person engineering organization evaluating a switch from Slack depends on answers Buzz cannot yet provide: a business model, a mobile client, a migration path from GitHub, and evidence from reference deployments beyond Block’s own BuilderBot. The platform is a credible architectural foundation and an early technical statement about what workplace infrastructure for the agent era should look like. The enterprise market will decide whether that statement is worth the switching cost.
Frequently Asked QuestionsWhat makes Buzz different from adding an AI bot to Slack?
Slack bots and most AI integrations operate under a service account or API key, with no cryptographic link between the agent’s action and the human who authorized it. Buzz gives every AI agent its own secp256k1 keypair and a second signature tying it back to its human owner. That means every message, commit, workflow step, and approval the agent takes is recorded in a tamper-evident signed event log that makes human authorization legible and traceable by default — something that cannot be reconstructed after the fact from Slack’s audit logs.
Can teams self-host Buzz to keep their code and conversations off Block’s servers?
Yes. The Buzz relay is open-source (Apache 2.0) and designed to run on your own infrastructure. Organizations with strict data-sovereignty requirements can run their own relay, keeping all messages, code, and agent activity on infrastructure they fully control. The self-hosted path requires Docker, Rust 1.88 or later, Node 24 or later, and pnpm. Block also operates a free hosted relay currently in beta with no usage limits, for teams that do not need full infrastructure ownership.
Will Buzz replace GitHub, or does it require a GitHub account?
Buzz includes a built-in Git software forge using standard Git Smart HTTP, which means teams can host repositories and manage code reviews entirely within Buzz without a separate GitHub account. Feature branches become dedicated channels where patches, CI results, and review comments are stored alongside the discussion that produced them. Teams can also connect existing external repositories. The platform supports Goose, OpenAI Codex, and Anthropic Claude Code as agent harnesses through the open Agent Client Protocol standard.
What is the liability and accountability case for using Buzz in an enterprise setting?
As organizations deploy AI agents that take real actions — submitting code, triggering payments, merging changes — the question of which human is responsible for an agent’s error is increasingly a legal and compliance question, not just an operational one. Buzz’s signed event log provides a built-in answer: every agent action is cryptographically linked to the human owner who authorized the agent, creating a chain of custody that persists in the audit record. For organizations under regulatory scrutiny or governance requirements around AI deployment, this architecture may become a compliance floor rather than a feature.