# x0x

Agent-to-agent gossip network for AI systems. Built on `ant-quic` (QUIC with
post-quantum crypto and NAT traversal) and `saorsa-gossip` (epidemic broadcast,
CRDT sync, pub/sub). Shipped as the `x0x` crate, the `x0xd` daemon (local REST +
WebSocket API) and the `x0x` CLI. Non-Rust apps talk to `x0xd` over HTTP; there
are no FFI bindings.

## Reference docs (read when relevant)
- REST + WebSocket API: `docs/api-reference.md`
- Tests, e2e harnesses, VPS ports: `tests/AGENTS.md`, `TEST_SUITE_GUIDE.md`
- Self-update: `docs/upgrade-system.md` · CI/CD: `docs/cicd.md`
- Trust, connectivity, announcements: `docs/trust-and-connectivity.md`
- Remote exec + ACL: `docs/exec.md`, `docs/design/x0x-exec.md` · Connect ACL: `docs/connect-acl.md`
- Signed-KV legacy compatibility: `docs/legacy-compat.md`
- Named groups: `docs/design/named-groups-full-model.md` · Symphony: `docs/symphony-integration.md`
- Non-Rust integration: `docs/local-apps.md`

## Build and test
- `just --list` for recipes. Local format, lint and docs checks (a subset of CI):
  `cargo fmt --all -- --check`,
  `cargo clippy --all-targets --all-features -- -D warnings`, and
  `RUSTDOCFLAGS="-D warnings" cargo doc --all-features --no-deps`.
  Passing them is not a full preflight. The `main` ruleset requires the
  Format Check, Clippy Lint, Test Suite, Documentation and Build linux-x64-gnu
  checks, and CI also runs coverage, parity, integration and
  deployment-authority jobs; see `.github/workflows/` for the full set.
- `ant-quic` and `saorsa-gossip-*` are exact-pinned (`=`) crates.io versions in
  `Cargo.toml`, and `Cargo.lock` is tracked. CI and release builds use
  `--locked`, so a dependency bump is a deliberate `Cargo.toml` + `Cargo.lock`
  change. Local work against sibling checkouts (`../ant-quic`, `../saorsa-gossip`)
  needs a temporary `[patch]`, which must not be committed.
- **Running tests needs isolation.** Test daemons join the real network, so test
  execution only runs inside a fresh loopback-only Linux network namespace with
  dropped privileges; macOS/Windows fail closed. Use `just test` / `just test-full`
  or `python3 scripts/dev/test-isolated.py nextest --all-features -- -E 'test(identity)'`
  (contract: `nextest <build flags> -- <runtime flags>`). Plain `cargo test` /
  `cargo nextest run` bypasses the isolation — only use it on a selector you've
  confirmed is inert. Evidence lands in `target/dev-isolation/run-*`.
- Linux cross-build: `cargo zigbuild --release --target x86_64-unknown-linux-gnu --bin x0xd`.

## Architecture

Identity is three layers; every ID is SHA-256 of an ML-DSA-65 public key:
- **Machine** (`~/.x0x/machine.key`, auto-generated) — QUIC transport identity; equals the ant-quic PeerId.
- **Agent** (`~/.x0x/agent.key`, auto-generated) — portable across machines.
- **User** (`~/.x0x/user.key`) — optional human identity, **never auto-generated**; issues an `AgentCertificate` binding agent to user.

Keys are bincode-serialized via `storage.rs`, not JSON.

Stack, bottom to top:
1. `network.rs` — wraps `ant_quic::Node`, implements `GossipTransport`. ant-quic owns mDNS, UPnP, bootstrap cache and connection orchestration.
2. `bootstrap.rs` — retry/backoff for the hard-coded seed hints. `DEFAULT_BOOTSTRAP_PEERS` is defined in `network.rs`; it lists UDP/443 first (preferred, traverses networks that block higher UDP ports) and keeps UDP/5483 for pre-ADR-0011 clients. Seeds are hints only.
3. `gossip/` — thin orchestration over `saorsa-gossip-*`; `GossipRuntime` owns `PubSubManager`.
4. `presence.rs` — beacons on the Bulk stream, phi-accrual failure detection, FOAF discovery with trust-scoped visibility.
5. `crdt/` (task lists), `kv/` (replicated KV with access policies), `mls/` (group encryption), `groups/` (named groups; DHT-free discovery via social propagation, BLAKE3 tag shards and presence). Deltas of a group-scoped task list (`x0x.group.<gid>.symphony.<lid>`) in an `MlsEncrypted` group are sealed with the group's current GSS/TreeKEM key, like group KV stores (`crdt/sealed.rs`, #895); personal lists and `SignedPublic` groups stay plaintext.
6. `server/` + `api/` — `x0xd` REST/WS; `src/api/mod.rs` is the shared endpoint registry that keeps routes and CLI subcommands (`src/cli/`) in sync. `gui/` is embedded HTML via `include_str!`.

Errors: `IdentityError`, `NetworkError`, `PresenceError` in `error.rs`.
`lib.rs` allows `unwrap_used`/`expect_used` crate-wide for tests; production paths still use `?`.

`x0x exec` is off unless the exec ACL (`/etc/x0x/exec-acl.toml`, macOS `/usr/local/etc/x0x/exec-acl.toml`) sets `[exec].enabled = true`.

`x0xd` flags worth knowing: `--name` (multi-instance), `--api-port`,
`--no-hard-coded-bootstrap` (config peers kept), `--relay`, `--check`, `--doctor`.
Example: `x0xd --name alice --api-port 12701 --no-hard-coded-bootstrap`.

## Documentation and communication

The documentation and communication style is in `docs/documentation-style.md`.

## Architecture decisions (ADRs)
Before changing architecture, protocols, storage formats, crypto, network
behaviour, public APIs or operational invariants, check `docs/adr/` and its
status overlay. During transfer, new or changed decisions use the numbered
ADR series only, through `docs/adr/TEMPLATE.md` and the ADR 0087 process
(D199). Accepted ADRs are immutable. Supersede them instead. Only David marks
an ADR Accepted.

The 15-slot direction, A01 through A15, is confirmed by David (D198).
David accepted the transfer on 10 Oct 2026. Slot files stay Proposed.
Mapped numbered records are the historical archive. Their `docs/adr/` paths
stay as links, and the bytes live in `docs/adr-archive/`. Read
`docs/adr/consolidated/README.md` for the transfer rules. Do not create A16
or a second consolidated series. Reserved numbered ADRs remain reserved:
0090/0091 (D18), 0097 (D20), 0098 (D35), and 0084–0105 (D63).
Slices 0109–0114 continue to acceptance as numbered ADRs. The accepted
records, overlay, frozen evidence and team gates remain in force.
ADR 0115 and ADR 0116 are outside the transfer map and outside the count.
Run `python3 scripts/check-adr-consolidation.py` for the transition checks.
Run `python3 scripts/check-adr-count.py` for the current-count limit of 15.
The plan is `docs/adr/consolidated/README.md`.