AICodeKing

nader dabit

Flavio Copes

<p>Block has launched Buzz, a free, open-source team workspace that lets AI agents participate as full members alongside humans — not as bots bolted onto the side, but as peers with their own cryptographic identities, channel memberships, and signed message history.</p>
<p>Jack Dorsey has positioned it as a replacement for both Slack and GitHub within Block. It’s early — version 0.4.21, released July 21st — but the architecture underneath it is more thought-through than most “AI-native” tools that have launched recently.</p>
<h2>How identity works</h2>
<p>Every actor in Buzz, human or agent, holds a secp256k1 keypair. Every action — chat message, reaction, git patch, membership change, workflow trigger — is a signed Nostr event. The relay stores and forwards these events but doesn’t rewrite them, so authorship is tamper-evident at the message level.</p>
<p>Agents get a second layer on top of that: an Owner Attestation, a tag that an owner key signs to authorize a specific agent key to act. The event stays authored by the agent; the attestation is a portable, verifiable statement of who permitted it. The grant can be scoped to specific event types or time windows, and you can’t attest for yourself — owner and agent keys must differ, enforced at both signing and verification time.</p>
<p>This separation of authorship from authority is the core design idea. The comment in the source code puts it plainly: “Don’t trust the relay — verify ourselves.”</p>
<h2>The technical stack</h2>
<p>The backend is 26 crates of Rust, organized as a modular monolith. Postgres stores events in a monthly-partitioned table scoped per community, with denormalized read models for channels, threads, reactions, mentions, and an audit log. Redis handles cross-node fan-out and presence. S3-compatible storage handles media.</p>
<p>The event model uses a <code>kind</code> integer as the only dispatch switch. About 130 kinds are defined as a closed list — an unrecognized kind is refused at ingestion. A new feature is typically a new kind. Chat messages, git patches, agent memory, moderation actions — same envelope, different kind.</p>
<p>A few delivery characteristics worth knowing if you’re building on this:</p>
<ul>
<li>When the relay answers OK, it means the event row was durably written — not that it was delivered.</li>
<li>Live delivery is at-most-once, without acknowledgement. A slow reader’s frames get dropped.</li>
<li>There’s no relay-assigned sequence number. Events are ordered by author-set timestamps, bounded to 15 minutes of drift. Arrival order, live delivery order, and replay order can all differ.</li>
<li>Recovery is pull-based: clients reconnect and re-request from a watermark. The agent harness builds at-least-once on top of this, up to a hard cap of 2,000 events per filter.</li>
</ul>
<p>The audit log is enqueued alongside event writes but not committed atomically — it’s best-effort, not a second guarantee.</p>
<h2>How agents actually connect</h2>
<p>Agents join through a harness called <code>buzz-acp</code>. The harness holds the agent’s Nostr key, subscribes to channels, batches inbound events, and manages a pool of agent subprocesses. The model itself sits underneath, kept identity-blind — it reaches the network only through a tool that attaches the owner attestation to each signed event. The model never holds the keys.</p>
<p>Supported agent harnesses include Codex, Claude Code, and Block’s own Goose framework (which has 50K+ GitHub stars and handles 200K+ operations daily at Block). Each connects through an ACP adapter. Buzz launches a fresh adapter process rather than attaching to an already-running session.</p>
<p>The runtime speaks to Anthropic, OpenAI-compatible, and Databricks providers. It summarizes and compacts its own context when the window fills, and runs tools through per-session subprocess servers with a scrubbed environment. Up to 32 agent subprocesses can run concurrently, with at most one prompt in flight per channel.</p>
<p>Local models work two ways. The straightforward route is any OpenAI-compatible endpoint — point it at a local vLLM or Ollama server. There’s also a feature-gated shared-compute path built on MeshLLM that can route requests across machines over direct encrypted QUIC, running GGUF models sized to available memory. It’s off by default, and CPU-only viability for the full agent path is noted as unproven.</p>
<h2>What’s actually in the workspace</h2>
<p>Beyond chat, Buzz includes:</p>
<p><strong>Git hosting.</strong> Patches, pull requests, issues, and status changes are ordinary signed events stored on the relay. The relay doesn’t merge or detect conflicts — agents reconstruct repository state from the event log themselves.</p>
<p><strong>YAML workflow engine.</strong> Channel-scoped workflows fire from post-store hooks, cron schedules, or webhooks. One capability is explicitly marked as not yet wired: approval gates. The relay has a complete grant-and-resume path for approval steps, but the piece that creates an approval is never called in production — only in tests. A workflow that asks for approval today fails rather than waits.</p>
<p><strong>Full-text search, direct messages, presence, and read-state sync.</strong> DMs use NIP-59 gift-wrap encryption — the relay stores the wrapper opaquely and can’t read the content, though it still sees the authenticated submitter. Presence and typing indicators ride ephemeral event kinds that are never stored.</p>
<p><strong>Push notifications</strong> that carry no message content — just a “reconnect” signal. The client refetches through the relay. No message bytes transit Apple or Google’s servers.</p>
<p><strong>Media handling</strong> with metadata stripping (GPS and EXIF rejected), a 25-megapixel decompression-bomb cap, and video restricted to a single H.264/AAC MP4 track.</p>
<h2>Multi-tenancy and isolation</h2>
<p>Multiple communities can share one relay. Community scopes every database key, every cache topic, and every audit chain. Cross-community recipients are dropped on every send. The source is honest that this isolation is a lint-and-review boundary — a reviewed convention rather than a compiler guarantee.</p>
<p>Buzz also ships an independent conformance checker: a separate program that re-implements the platform’s formal specification from scratch, depends on none of the production code, and replays execution traces against it. The checker’s own documentation notes that coverage is execution- and seam-bounded, and broad integration replay was still ahead at the current commit.</p>
<h2>What’s missing</h2>
<p>The project is candid about what isn’t done yet:</p>
<ul>
<li>Mobile clients are unfinished</li>
<li>Push notifications are pending</li>
<li>Workflow approval resumption isn’t wired in production</li>
<li>Some workflow actions lack complete execution paths</li>
<li>Git integration is early</li>
</ul>
<p>Self-hosting requires running the relay, Postgres, Redis, and S3-compatible object storage. There’s also a free hosted relay from Block if you don’t want to run your own.</p>
<h2>Where things stand</h2>
<p>Buzz grew out of Block’s earlier agent work — Goose and a Slack-based prototype called BuilderBot. The repository is Apache 2.0 licensed. Desktop apps are available for macOS, Windows, and Linux.</p>
<p>The identity model and agent coordination are notably polished for a 0.4 release. The delivery guarantees and missing features mean it’s not production-ready for most teams yet. But the architecture — one signed-event substrate for every action, authority separated from authorship at the message level, agents as genuine peers rather than integrations — is a more coherent foundation than most tools in this space have started with.</p>


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Block has released Buzz, an open-source workspace built on the Nostr decentralized protocol that integrates AI agents and humans in shared channels, threads, and DMs. Each agent receives its own cryptographic keypair plus a second signature linking it to a human owner, creating a verifiable audit trail. Agents connect via the Agent Client Protocol (ACP) and can search discussions, submit patches, review code, and run workflows. Built-in support ships for Goose, Codex, and Claude Code, with any agent framework connectable. The tool aims to replace Slack and GitHub with a unified identity system covering chat, Git hosting, and workflow automation. Teams can self-host their own Nostr relay or use Block's free hosted relay, though each deployment relies on a single authoritative relay rather than being truly peer-to-peer. Currently at version 0.4.21, Buzz is early-stage with mobile clients and push notifications still pending. It is Apache 2.0 licensed.

Jack Dorsey launches Buzz, an open-source workspace that gives AI agents their own cryptographic identity