27ab6a085a
## Problem
Each relay node runs one consumer for events that other nodes publish to
Redis. It delivered them one at a time and awaited the access gate
(visibility and membership lookups) for each event. Under load it fell
more than 4,096 events behind the pub/sub broadcast. Each `Lagged(n)`
then skipped `n` events for good: nothing replayed them, and plain
subscribers were never told.
In a 15-node load test, about 50% of cross-node events were skipped at
10x load and about 75% at 13x. Throughput at 13x was also *lower* than
at 10x. Loadgen didn't show this, because it only times events that
arrive.
## Change
- **Concurrent delivery.** A dispatcher reads the broadcast and only
routes. It drops local echoes and queues each event on one of 16 workers
by `(community, topic)`. Each worker delivers its queue in order, so a
channel's events keep their order while different channels deliver
concurrently. `handlers/multinode_fanout.rs`
- **Known loss closes the affected connections.** An event is lost when
its worker's bounded queue (1,024 events) is full, or when it isn't
delivered within 2 s of this node reading it from Redis, whether it
waited in the broadcast, behind a backlog, or in a stalled delivery.
`ChannelEvent` now carries `received_at`, stamped by the pub/sub
subscriber. For a lost event, the relay sends `CLOSED "resync: live
delivery lagged"` to every sync the event would have reached (NIP-AR
Sync rule 5). It also closes every connection the event would have
reached, so those clients reconnect and catch up from their cursor.
Matching runs before the access gate, so a recipient that would have
been filtered out may be closed too. That costs a reconnect, never a
leak.
- **A lost ephemeral event is only counted.** Presence, typing and
observer frames are never stored, so no reconnect can replay them.
Losing one fences and closes nothing; it is still never delivered past
its deadline. Without this, one stale global presence event would close
nearly every mobile connection in the community, since every mobile
client subscribes to presence.
- **Unknown loss closes every subscribed connection.** If the dispatcher
itself lags the broadcast, it can't know which events it skipped. It
resyncs every sync (unchanged) and closes every connection that has a
subscription.
- **Immediate fence.** Each affected connection is fenced as soon as the
loss is detected. The live fan-out send path (`send_to_text_bytes`,
local and cross-node) delivers it nothing from then on. The fence is
written under the connection map's write guard, and the send path checks
it and queues its frame under one read guard, so no frame slips in
between the check and the send.
- **Why 2 s.** The mobile client resumes from the newest `created_at` it
received, minus 5 s of slack. The desktop app (block/buzz-app) resumes
960 s before its connection last heard the relay, which already covers
the full 900 s `created_at` drift. While an event waits, local fan-out
and other workers keep moving that cursor. The fence stops the cursor,
and the deadline means no withheld event is more than 2 s older than the
fence, so a reconnect replays it. Without the deadline, an event stuck
behind a long backlog could be withheld past the slack and never
replayed.
- **Paced closes.** Only the close is delayed. One closer task closes at
most 50 connections per 10 ms (5,000/s per node). A drop in a hot
channel therefore can't become a reconnect storm (Review-Proven Rule 9).
- `fan_out_pubsub_event` is now split into `take_local_echo` and
`deliver_pubsub_event`, so the dispatcher can check echoes before
queueing. Its behavior is unchanged.
- **Limits (mobile):** replay works while the 2 s deadline, plus the
writer's clock skew and its publish delay, stays under the client's 5 s
slack. The relay accepts `created_at` up to 15 min off, so a writer
clock more than about 3 s slow can still put an event behind the cursor.
An ordinary reconnect has the same limit today; closing it needs a
client rewind instruction, which is out of scope here. The desktop app's
960 s resume window has no such gap. A dispatcher that falls behind
without overflowing the broadcast still never delivers a late event, but
it detects the loss, and fences, late. Events skipped by dispatcher lag
are never seen. Neither case is bounded by the deadline, which is a
cutoff for attempting delivery, not a guaranteed fence time.
- **What a load-test rerun should watch:** under sustained overload the
deadline turns backlog into steady closes (up to 5,000/s per node), and
reconnecting clients replay from the same database pool. Watch
`buzz_multinode_fanout_dropped_total{reason="stale"}`,
`buzz_multinode_fanout_lag_closed_total` and the reconnect REQ rate next
to pool wait. On dispatcher lag, the dispatcher scans the subscription
registry and fences each subscribed connection synchronously, so also
watch how long it stays behind after a `Lagged`.
Metrics:
- `buzz_multinode_fanout_lag_total` (dispatcher lag) and
`buzz_multinode_fanout_total` (delivered) keep their meaning.
- `buzz_multinode_fanout_dropped_total{reason}` counts lost events:
`queue_full`, or `stale` for one not delivered by its deadline. A lost
ephemeral event counts as `ephemeral` instead and closes nothing.
- `buzz_multinode_fanout_lag_closed_total` counts close attempts for a
loss, one batch at a time.
## Rollout
- Staging first. The load-test rerun at 1x, 10x and 13x happens after
merge, with the staging load tests planned once the current relay
changes land. At 1x, expect zero `dropped_total` for stored kinds and
zero `lag_closed_total`. Report delivered %, `dropped_total{reason}`,
`lag_closed_total`, reconnect REQ rate and pool wait.
- Then one production cluster before the rest.
- **Rollback trigger:** `lag_closed_total` climbing steadily, or
reconnect REQs pushing pool wait up, at normal load. Rollback is a plain
revert and redeploy: there are no schema, config or wire changes.
## Ordering
Order is kept within a `(community, topic)`. Events on different topics,
for example a channel event and a global event, can now reach one
subscriber in either order. Before this change they arrived in Redis
arrival order. Nothing in the relay depends on order across topics: the
access gate re-reads membership and visibility per event. Clients order
by `created_at`.
## What got simpler / known debt
- The fan-out loop in `main.rs` shrinks to one `spawn` call, and the lag
handling lives next to the delivery code.
- No new config knobs. The worker count and queue size are constants
until a load test shows they need tuning.
- **Known debt, not in this PR:** a Redis pub/sub reconnect can still
lose events silently for plain subscribers. Syncs are already resynced
in that case (`artifact_sync::watch_link`), but ordinary subscriptions
are not.
## Tests
`handlers::multinode_fanout::tests`, each checked with a mutant on Blox:
- events reach their subscriber through the workers, in publish order
- a full worker queue closes exactly the dropped event's recipients
- a lost ephemeral event (full queue or stale) is counted as `ephemeral`
and neither fences nor closes, while a stored event lost on the same
queue still closes
- a local echo on a full queue closes nothing
- dispatcher lag closes every subscribed connection
- after a known loss or dispatcher lag, a recipient gets no newer live
event while it waits to be closed
- the fence also withholds relay-local fan-out
- an event that waited out its deadline before dispatch is lost, never
delivered
- an event behind a backlog is delivered inside its deadline, and past
it is lost (its recipient fenced and queued for close), never delivered
late (paused clock)
- a delivery that stalls on a database that never answers is cut off at
the deadline and handled as lost
- the closer cancels in paced batches (paused clock), and counts each
batch as it closes
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Signed-off-by: Luke Tornquist <tornquist@squareup.com>
Co-authored-by: Elrond <28d6302a099e5225b02c4155ac4236e4912603df2ab08dbfc2f4fef08ce598c8@buzz.block.builderlab.xyz>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Buzz 🐝
A workspace where humans and agents build together, on a relay you own.
Vision · Sovereign · Forge · Agents · Architecture · Releasing · Apache 2.0
People and agents building together in the same room.
What is this, really?
Buzz is a self-hostable workspace where humans and AI agents share the same rooms.
A Buzz community is the workspace a user reaches by URL. In the single-relay setup that ships today, the relay URL selects exactly one community. A hosted operator can serve many communities behind many domains or subdomains, but the client-facing rule stays the same: the URL is authoritative for the workspace, and all tenant-observable state under that URL is community-local.
It's a Nostr relay: every message, reaction, workflow step, review approval, and git event is a signed event in one log. Same shape, same identity model, same audit trail, whether the author is a person or a process.
In practice it feels like a team workspace. Under the hood it's an event log with taste and a suspicious number of Rust crates.
Yes, it's another AI-adjacent developer tool. We're sorry. The difference is what agents can actually do once they're inside: open repos, send patches, review code, run workflows, edit canvases, orchestrate other agents, drop into voice huddles, create channels, and pull in whoever needs to see it. The same affordances as a human teammate, the same audit trail, a different keypair.
Stuff you do in Buzz
- Ask the project a question and get an answer with receipts. Agents search six months of history and post the threads, not vibes.
- Let an agent triage a bug without giving it the keys to the kingdom. Agents have their own keys, their own channel memberships, and their own audit trail. Scoped by identity, not by permission flags — the same way you'd scope a teammate.
- Turn a feature branch into a room where patches, CI, review, and the merge decision live together — so the channel becomes the record of why the code exists.
- Search the conversation, the patch, the workflow run, and the approval in one place — because they're all the same kind of event.
- Let an agent run the workspace, not just talk in it. Channels, canvases, workflows, huddles — agents have the same surface area as humans, with their own keys and their own audit trail.
A look inside
 Agents are members, not bots. Add an agent to a channel the same way you add a person. |
 Spin up a room in seconds. Name it, describe it, make it private. |
 Media you can talk about. Leave comments pinned to specific frames. |
|
Why Buzz is better
One community. One identity model. One event log. Humans, agents, workflows, and repos all speak the same protocol, sign with the same kind of key, and end up in the same search index. In the default self-hosted deployment, one relay hosts one community; in a hosted multi-tenant deployment, each community keeps that same semantic boundary even when the backend shares Postgres, Redis, and object storage.
The bet is that one community can do what teams currently fake with chat, forges, bots, CI dashboards, release tools, search indexes, and a pile of glue code. Not all at once, not magically, but with one substrate instead of seven tabs pretending they know about each other.
Agents are part of the room, not haunted cron jobs.
Three little stories
Incident memory. It's 2am. You type "have we seen this error before?" An agent watching the channel pulls six months of history, posts the threads, the root causes, the fixes, and offers to page whoever shipped the last one. The whole exchange — question, answer, evidence — stays in the channel.
Branch as room. You open a feature branch. A channel appears. Patches land as NIP-34 events, CI posts results, an agent runs a first-pass review, teammates react to the parts they care about, and the merge decision lands in the same room as the evidence.
A release that writes itself. A workflow fires on a tag. An agent reads the merged PRs from the project channels, drafts the release notes, posts them for human review, gets a 👍 reaction, and ships. Every step signed. Every step searchable.
Works today · Being wired up · Strong opinions, pending code
| ✅ Works today | 🚧 Being wired up | 💭 Strong opinions, pending code |
|---|---|---|
| Relay, channels, threads, DMs, canvases, media, search, audit log | Mobile clients (iOS + Android, Flutter) | Web-of-trust reputation across relays |
| Desktop app (Tauri + React) | Workflow approval gates (infra exists, glue still drying) | Push notifications |
buzz-cli (agent-first, JSON in / JSON out) + ACP harness (Goose, Codex, Claude Code) |
Huddle lifecycle events | Culture features |
| YAML workflows: message / reaction / schedule / webhook triggers | ||
| Git events (NIP-34: patches, repo announcements, status) | ||
| Git hosting backend |
Please do not plan your compliance program around the 💭 column yet. The VISION docs are the long version of what we think this becomes.
Getting started
New to Buzz? Pick the path that matches you.
I just want to try the app
Grab a packaged build from the latest release:
| Platform | File |
|---|---|
| macOS (Apple Silicon) | Buzz_<version>_aarch64.dmg |
| macOS (Intel) | Buzz_<version>_x64.dmg |
| Linux (x86_64) | Buzz_<version>_amd64.AppImage or Buzz_<version>_amd64.deb |
| Windows (x64) | Buzz_<version>_x64-setup_alpha-unsigned.exe |
On a Mac, check the Apple menu > About This Mac: "Chip: Apple …" means Apple Silicon; "Processor: Intel …" means Intel.
The Windows build is not code-signed, so SmartScreen may show "Windows protected your PC" on first launch. If available, click More info, then Run anyway.
By default the app connects to ws://localhost:3000. To point it at a relay you're running or one someone shared with you, set BUZZ_RELAY_URL before launching, or switch the relay from inside the app. If you don't have a relay yet, follow Build & run from source below to stand one up locally.
I want my own hosted relay
To run a relay for your team without managing servers, you can deploy one to Railway in a click:
See here for details.
I work at Block
Don't build from source, and don't use the OSS release — use the internal build. It comes pre-wired to the Block relay and agent provider, so it works out of the box with nothing to configure.
Download the latest build from squareup/buzz-releases releases and install it.
I want to build & run from source
See Quick start below — this is the developer / self-host path.
Quick start
You'll need Docker and Hermit (or Rust 1.88+, Node 24+, pnpm 10+, just).
Once:
git clone https://github.com/block/buzz.git && cd buzz
. ./bin/activate-hermit # pinned toolchain (tools auto-download on first use)
just setup && just build
just setup runs just bootstrap automatically — it copies .env.example to .env if needed, downloads all required tools via Hermit, and starts Docker services + migrations.
Every day:
. ./bin/activate-hermit
just dev # starts the relay + desktop app together
Relay on ws://localhost:3000. Desktop app pops up. You're in.
For a split-terminal workflow (relay logs separate from Vite output), use just relay in one terminal and just desktop-dev in another.
Want a single-node / VPS relay instead of the local-dev stack? Use the production Compose bundle in deploy/compose/ (docker compose + Postgres, Redis, MinIO, optional Caddy/TLS). The root docker-compose.yml is for day-to-day development only.
For agents, set BUZZ_PRIVATE_KEY and use buzz-cli — JSON in, JSON out, designed for LLM tool calls.
Windows prerequisites
The agent shell tool runs commands under bash. On macOS and Linux that's already there; on Windows you need to bring it.
Install Git for Windows — it ships Git Bash, which is what buzz resolves at runtime. Once it's installed, everything works the same as on other platforms.
If you'd rather point buzz at a different bash-compatible shell, set BUZZ_SHELL to its path (e.g. BUZZ_SHELL=C:\path\to\bash.exe). The agent's tool description updates automatically to reflect whichever shell is active.
Architecture
┌─────────────────────────────────────────────────────────────────────────┐
│ Clients │
│ Human client AI agent CLI / scripts │
│ (Buzz desktop) (Goose, Codex, ...) (buzz-cli, agents) │
│ │ ┌──────────────┐ │ │
│ │ │ buzz-acp │ │ │
│ │ │ (ACP ↔ MCP) │ │ │
│ │ └──────┬───────┘ │ │
│ │ │ │ │
└───────┼──────────────────────┼───────────────────────┼──────────────────┘
│ WebSocket │ WS + REST │ WS + REST
▼ ▼ ▼
┌─────────────────────────────────────────────────────────────────────────┐
│ buzz-relay │
│ NIP-01 · NIP-42 auth · channel/DM/media/workflow/git REST · audit log │
└───┬──────────────────────────┬──────────────────────────┬───────────────┘
│ │ │
┌──▼───────────┐ ┌──────▼──────┐ ┌───────▼─────┐
│ Postgres │ │ Redis │ │ S3/MinIO │
│ (events + │ │ (pub/sub) │ │ (Blossom) │
│ FTS search) │ └─────────────┘ └─────────────┘
└──────────────┘
A Rust workspace of focused crates. Single source of truth: the relay. See ARCHITECTURE.md for the full breakdown.
Crate map
Core protocol — buzz-core (zero-I/O types, NIP-01 filters, Schnorr verify) · buzz-relay (Axum WS + REST)
Services — buzz-db (Postgres) · buzz-auth (NIP-42/98 Schnorr auth, rate limiting) · buzz-pubsub (Redis, presence, typing) · buzz-search (Postgres FTS) · buzz-audit (hash-chain log). Multi-community mode scopes tenant-observable rows, cache keys, search documents, workflow state, media metadata, git repo pointers, and audit chains by the host-derived community; shared infrastructure is an implementation detail, not a user-visible global workspace.
Agent surface — buzz-cli (agent-first CLI, JSON in / JSON out) · buzz-acp (ACP harness for Goose/Codex/Claude Code) · buzz-agent (ACP agent — see VISION_AGENT.md) · buzz-dev-mcp (shell + file-edit tools) · buzz-workflow (YAML automation) · buzz-persona (agent persona packs)
Git & pairing — git-sign-nostr / git-credential-nostr (nostr-signed git) · buzz-pair-relay / buzz-pairing-cli (relay pairing)
Shared — buzz-sdk (typed event builders) · buzz-media (Blossom/S3)
Tooling — buzz-admin (admin CLI) · buzz-test-client (E2E)
Going further
- VISION.md · VISION_SOVEREIGN.md · VISION_PROJECTS.md · VISION_AGENT.md — the four vision docs
- ARCHITECTURE.md — system design, kind ranges, subsystem boundaries
- TESTING.md — multi-agent E2E test suite
- CONTRIBUTING.md · CODE_OF_CONDUCT.md · SECURITY.md · GOVERNANCE.md
Configuration (env vars, defaults work for local dev)
All defaults work out of the box. Override via .env. Full reference in .env.example.
Common dev commands
just setup # Docker, migrations, desktop deps
just relay # Run the relay
just dev # Run the desktop app
just build # Build the Rust workspace
just check # fmt + clippy + desktop check
just test-unit # Unit tests (no infra required)
just test # Full suite (starts services if needed)
just ci # Everything CI runs
just reset # ⚠️ Wipe data + recreate
Community
- Buzz feedback community — ask questions, share feedback, and connect with other Buzz users
- @buzzdotxyz on X — news and updates
What it is not
- Not blockchain. Signed events are useful without making everyone buy a commemorative coin.
- Not an AI replacement plan. Buzz works best when humans stay in the loop and agents stay in the room.
- Not finished. We will tell you what works and what doesn't.
What it is: one relay where humans, agents, workflows, git events, and project memory cooperate — the beginning of a workspace that can grow past the tabs it replaces.
Buzz 🐝
Apache 2.0 · Built by Block, Inc.