5b1698ec24
## Problem
The replica-fence probe (`replica_fence::run_probe`) commits a heartbeat
token every 500 ms. It borrowed its connection from the **serving writer
pool**, so under load each beat queued behind request traffic.
In a production deployment during a reconnect/replay storm:
-
`buzz_db_pool_acquire_duration_seconds{pool_role="writer",operation="maintenance"}`
went from ≤50 ms max to 2.7–3.0 s, which is the writer pool's acquire
timeout.
- `buzz_db_replica_heartbeat_age_seconds` went from about 0.47 s to
1.25–3.02 s, in the same 10 s buckets.
- Bounded reads then failed the freshness check
(`buzz_db_route_decision{decision="writer",reason="stale"}` went from
0–6 to 1.3k–6.4k per 10 s), so read traffic spilled onto the writer
exactly when it was saturated. Replica lag stayed at tens of
milliseconds the whole time.
- No `replica fence probe failed` warning fired, because each beat
eventually succeeded, just late. The probe had no span or metric of its
own (`maintenance` is shared by 15+ call sites), so this was only
visible indirectly.
## Change
- **Dedicated pool** (`replica_fence::connect_probe_pool`):
- lazy, one connection, `application_name=buzz-replica-fence-probe`;
- same credentials and `max_lifetime` as the writer, so it follows
failover;
- modelled on the push producer's pool.
- It doesn't run the writer pool's `after_connect`: the probe never
writes `events`, so no floor-guard arming is needed. Instead it installs
its own session timeouts:
- `lock_timeout` 1 s. While the probe waits for the exclusive floor
lock, new channel writes queue behind it, so failing a beat fast is
cheaper than holding the queue for the serving writer's 5 s budget.
Retained proofs stand.
- `statement_timeout` and `idle_in_transaction_session_timeout` 2 s. The
idle timeout reaps a stalled client that still holds the exclusive lock.
- A 5 s client-side deadline bounds the whole probe.
- Cost: one extra writer connection per relay process.
- The `Db::connect_writer_pool` doc now names this pool and the
push-enqueue pool as deliberate exceptions to its "every writer pool
uses this constructor" rule, and says why.
- **Spans** (via `datastore_span`, which also records
`buzz_db_operation_duration_seconds{operation=…}`):
- `replica_fence_probe` carries `acquire_ms`, `lock_ms`, `scan_ms`,
`heartbeat_ms`, `commit_ms`, `beat_gap_ms`, `token` and `error_kind`.
- Child spans `replica_fence_probe_acquire` and
`replica_fence_probe_lock` cover the two waits.
- **Logs:**
- Failure: `warn` with `error_kind` (`acquire_timeout`, `lock_timeout`,
`statement_timeout`, `deadline`, `masked_activity`, …),
`consecutive_failures`, `heartbeat_age_ms` and per-phase timings.
- Recovery after failures: `info`.
- **Reader spill metric:** new `buzz_db_reader_spill_total{path,
reason}`. It counts only the routed reads the replica could have served
but the writer did. `buzz_db_route_decision{decision="writer"}` already
existed but merges three different causes under `reason="stale"` and
also counts configuration (`disabled`). Reasons:
| Reason | Meaning |
|---|---|
| `heartbeat_stale` | The newest beat is older than the bounded-read
budget. The probe is late, not the replica. |
| `heartbeat_missing` | No live proof: before the first beat, or nothing
within `FENCE_STALENESS`. |
| `fence_wall_behind` | The read's upper bound is newer than the fence
wall. |
| `replica_lag` | The session proved only an older entry than the read
needs. |
| `reader_acquire_timeout` | Couldn't check out a reader connection. |
| `reader_proof_timeout`, `reader_token_behind`,
`reader_validation_error` | The reader couldn't prove the fence. |
`buzz_db_route_decision` keeps its labels and values unchanged for
existing dashboards. History reads rejected on a saturated reader stay
`decision="rejected"` and aren't counted as spills.
- **Heartbeat interval versus budget:**
- The problem: at 500 ms beats, a 1000 ms `BUZZ_REPLICA_READ_MAX_AGE_MS`
tolerates no missed beat. Just before each commit the newest entry is
already about one interval old, so a single late or failed beat puts
every bounded read over budget.
- The default beat interval stays at **500 ms**. Every beat takes the
deployment-wide exclusive floor lock that channel writes queue behind,
so beating faster costs more lock drains. The budget is what should
absorb a slow beat.
- New `min_read_budget(interval)` = interval + `PROBE_LOCK_TIMEOUT` (1
s) + 200 ms, which is **1700 ms** at the default. That covers one beat
that waits out the lock timeout, plus commit latency. `Db::new` warns at
startup when the configured budget is below it. A deployment running a
1000 ms budget will see this warning until the budget is raised.
- The interval is now configurable with
`BUZZ_REPLICA_FENCE_PROBE_INTERVAL_MS`. Unset means the 500 ms default.
Values outside 300–10000 ms fail startup. The 300 ms floor keeps the
120-entry proof ring covering more than the 30 s staleness gate, and the
ring assertion checks against that floor.
The proof ordering is unchanged: exclusive lock, then `S`, then activity
scan, then token commit last. `committed_at` is still captured before
the `UPDATE` round trip.
## Tests
- New `fence_probe_beats_while_serving_writer_pool_is_exhausted`: goes
through `Db::new` + `spawn_fence_probe`, holds the serving pool's only
connection, and requires two fresh beats and exactly one probe session.
It fails on `main`'s wiring, which I checked by temporarily reverting
the `spawn_fence_probe` change.
- New `cluster_global_probe_pool_bounds_the_floor_lock_wait`: a held
shared floor lock makes the probe fail with `lock_timeout` after about 1
s, the retained proof survives, and the next beat succeeds after
release.
- New `reader_spills_are_counted_by_cause`:
- fresh heartbeat → no spill;
- late heartbeat → `heartbeat_stale`, with the legacy `stale` still
emitted;
- past the staleness gate → `heartbeat_missing`;
- routing disabled → no spill.
- Unit tests cover the log throttle and the interval/budget helpers. The
epoch-rotation test now runs through the one-connection probe pool.
- The `observability_source` source-policy test now asserts the probe
never takes a serving-writer `Maintenance` checkout and is spawned
through `connect_probe_pool`.
- Existing replica-fence and `spawn_fence_probe` tests pass unchanged,
apart from signature updates.
## Not done / follow-ups
- Locally: `buzz-db` unit tests and clippy (`-D warnings`) pass, and 38
replica-fence and routing Postgres tests pass on a fresh database. I
didn't run the full Postgres suite, because it needs the nextest
per-test-database wrapper, so CI's Postgres lane is the gate there.
- No local relay run yet. This needs a reader-configured relay, then
pool exhaustion to see the spans and logs end to end.
- The deployed `BUZZ_REPLICA_READ_MAX_AGE_MS` lives in deployment
config. Check it against the new startup warning.
- The `PROBE_DEADLINE` path has no test. It's only reachable through a
stall that no server-side timeout catches.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Signed-off-by: Jemiah Westerman <jemiah@squareup.com>
Co-authored-by: Son of Anton <8e0ef2ab02d69a7ac089ef5eca90d1a3fbbdc546f6322dc34d0c4f3deecea7f4@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.