hyperhive/docs/process/conventions.md

# Conventions

Code-style and process expectations across the workspace. Most of these
exist because something already went wrong without them.

## Naming

- Containers are length-bounded by `nixos-container` (≤ 11 chars).
- Sub-agents are `h-<name>` with `<name>` ≤ 9 chars.
- One agent is the bootstrap/root container, with a fixed name (`ruth` today).
- `MAX_AGENT_NAME` in `hive-c0re/src/lifecycle/mod.rs` enforces the cap.
- Per-agent web UI port = `WEB_PORT_BASE + FNV1a(name) % WEB_PORT_RANGE`
  (8100..8999) for every agent; dashboard
  `cfg.dashboardPort` (default 7000).

## Hive identity (label + domain + display names)

Four env vars cover the identity surface, read by
`hive-agent/src/identity.rs`:

- `HIVE_LABEL` — short, hive-local agent label (`iris`,
  `damocles`). `label()` returns it; falls back to empty string if
  the env var is missing so downstream callers can decide how to
  surface "unknown agent" rather than getting a panic from this
  module.
- `HYPERHIVE_HIVE_DOMAIN` — the hive's canonical DNS domain (e.g.
  `darkest.space`), set by `nix/host-modules/hive-c0re/environment.nix`
  from `services.hyperhive.domain`. When configured, `qualified_label()`
  returns `${label}@${domain}` (e.g. `iris@darkest.space`); when
  unset (single-hive deployments, dev/test) it degrades to just
  the short label so existing callers see no change. The
  qualified form surfaces in the per-agent web UI title, the
  system-prompt template, and `/api/state.qualified_label`.
- `HYPERHIVE_HIVE_NAME` — human display name of this hive
  (`pr1ma`). Read by `hive_name()`; `None` when unset.
- `HYPERHIVE_SWARM_NAME` — human display name of the wider swarm
  this hive belongs to (`constellat1on`). Read by `swarm_name()`;
  federated hives at different DNS domains can share a swarm
  name.

`hive_name` + `swarm_name` are **distinct** from
`HYPERHIVE_HIVE_DOMAIN`: the domain may carry the hive name as
its leftmost label by convention, but the convention isn't
machine-readable, and federated hives at different DNS domains
can share a swarm name. Humans want both: the address
(`@darkest.space`) AND the prose name (`pr1ma`). Matrix MXIDs
still use the domain-based convention untouched.

`qualify(label)` is the same shape as `qualified_label()` but
applies to an arbitrary label the caller already has (e.g. a peer
name from the broker); it's the right surface when rendering a
peer's name when the caller knows it's hive-local.

## Identity = socket

There are no auth tokens on the per-agent unix sockets. The socket
*path* identifies the principal; perms come from "who has the
bind-mount." A sub-agent only sees its own `/run/hive/mcp.sock`;
hive-c0re owns the host admin socket.

### Wake injection

`AgentRequest::Wake { from, body }` (and the manager-flavour mirror)
is the wake-event-injection surface. Recipient is implicit — the
agent the socket belongs to — and `from` is caller-chosen so the
wake prompt can label the source verbatim (`"matrix: new message in
#general"`, `"forge: PR #42 opened"`, etc.). Typical caller: an
in-container background task (the matrix daemon, a scraper, the
forge-notify webhook subscriber) that needs to signal "external work
has arrived" without going through the broker as a peer agent.

Identity = socket means anything that can connect to
`/run/hive/mcp.sock` is implicitly trusted to inject wakes. That's
fine: the bind-mount only exposes the socket inside the agent's own
container, so the trust boundary is the container's process
namespace, not the wire surface.

## Recipient sentinels

A few recipient names are reserved by the broker and have special
meaning that ordinary agent labels can never collide with — agent
name validation rejects any character outside `[a-z0-9_-]`, so the
angle-bracket and asterisk shapes below are structurally safe.

- `*` — broadcast: deliver to every running agent except the sender
  (`socket_server::handle_send` fans out via `Coordinator::broadcast_send`).
- `operator` — the human at the dashboard. Messages accumulate in the
  inbox view; no agent ever `recv`'s them.
- `<parent>` — the sender's parent per `topology.json`. Rewritten at
  send time by `topology::resolve_recipient`: looks up
  `parent_of(sender)` and falls back to `operator` when the sender is
  a root agent (or absent from topology entirely). Lets agents address
  their parent without learning the label, so runtime reparenting
  propagates with zero agent-side restart.
- `<children>` — fan-out to every direct descendant of the sender per
  `topology.json`. Resolved in `socket_server::handle_send` via
  `topology::children_of(sender)`: one message is delivered to each
  child, bypassing the allow-list check (structural fan-out targets are
  never user-listed peers). No-op for leaf agents (returns `Ok` when the
  child set is empty). Lets a sub-manager nudge its subtree without
  enumerating labels.

When a `<children>` or `<parent>` send resolves to real recipients, the
broker stores the *resolved* label(s) as the message recipient(s) — the
dashboard and recv side see the real routes. The sentinels are purely
send-time addressing conveniences.

## Wire protocol

JSON line-delimited over unix sockets in both directions (host admin
/ manager / agent). SSE streams (`/dashboard/stream` on hive-c0re,
`/events/stream` on the per-agent web UIs) are `text/event-stream`;
each frame carries a `seq` field for the snapshot-dedupe dance
(see `docs/web-ui.md`). Request/response types live in `hive-sh4re`
— change them in one place. The dashboard event vocabulary lives
in `hive-c0re::dashboard_events::DashboardEvent`.

### Broker delivery + ack cycle

`AgentRequest::Recv` is the only path that delivers messages to an
agent. Always returns a list (`Messages { messages }`) — empty when
nothing's pending, single-pop when `max = None` (default 1, the
single-message behaviour), batched up to `max` when caller asks for
more (server-side cap is 5; values above clamp silently). The wire
request still carries an optional `wait_seconds` (long-poll the first
message, once one arrives — or one is already pending — the call
drains up to `max` in total): the harness's own turn-driving loop
uses it internally (`hive-agent`'s `recv_next`, 180s). The
agent-facing MCP `recv` tool does not expose this parameter — it
always passes `wait_seconds: None`, an immediate peek.

Per-row bookkeeping inside the broker:

- `delivered_at = NOW` set on every popped row.
- Each recipient has an in-memory `unacked_ids` list of every row
  delivered since the last `AckTurn`.
- `redelivered = true` on a row if `RequeueInflight` resurfaced it
  (the harness prepends a "may already be handled" hint when this
  flag is set so the per-message warning is visible).

`AgentRequest::AckTurn` closes out the in-memory list — the harness
fires it after `TurnOutcome::Ok`, marking every message popped since
the last ack as fully handled. Claude doesn't see this surface; it's
strictly a harness↔broker pairing. On `TurnOutcome::Failed` the
harness intentionally skips the ack so the unacked rows stay
in-flight in the DB and get picked up by the next requeue sweep.

`AgentRequest::RequeueInflight` is the recovery pair: fired by the
harness exactly once at boot, before the serve loop starts. Catches
the crashed-mid-turn / OOM-killed / container-restarted cases where
a previous harness session popped messages but never drove them to
a clean turn-end. Resets `delivered_at` back to NULL on every
unacked row (so the next `Recv` pops them again), and remembers
each id in a per-recipient in-memory set so the next `Recv` can tag
the row with `redelivered: true`. Idempotent + cheap when there's
nothing in flight, so the at-boot fire is unconditional.

`AgentRequest::AckUntil { up_to }` is the agent-facing bulk-triage
escape hatch (`mcp__hyperhive__ack_until`). Unlike `AckTurn` it IS
visible to claude: each recv row and wake prompt carries a
`[msg #<id>]` marker (the broker row id; transient pings show no
marker — their sentinel id 0 has nothing to ack), and
`ack_until(up_to: n)` marks every one of the agent's rows with
`id <= n` handled in a single UPDATE — pending and delivered alike.
This bounds the redelivered-flood cost after a restart: instead of
popping dozens of already-handled messages one turn at a time, the
agent notes the highest id it has seen and acks up to it.
Recipient-scoped (an agent can only ack its own rows); also drains
the in-memory `unacked_ids` / `requeued_ids` bookkeeping below the
cutoff so a later `AckTurn` doesn't double-update and a stale
redelivery tag can't outlive its row. The operator-side sibling is
the dashboard's "mark all read" (unbounded, per-agent).

### Loose-ends wire shape

`LooseEnd` is the per-row response shape for `GetLooseEnds` (both
the agent-flavour and manager-flavour requests). Tagged enum so
new thread kinds (forge PRs, long-running approvals from a
privileged bot, etc.) can land later without breaking existing
handlers. Each row carries enough context that the caller renders
it directly as a bulleted list, no follow-up fetch needed.

Per-flavour scoping is uniform across the two cancellable variants:

- **agent-flavour** `GetLooseEnds` only surfaces rows the calling
  agent has standing in. `Approval` rows only appear when the
  calling agent is the manager (sub-agents don't submit
  approvals). `Reminder` rows are scoped to `owner == self`.
- **manager-flavour** `GetLooseEnds` lists every pending row in
  the swarm — full audit view.

Per-variant fields:

- `Approval { id, agent, commit_ref, description?, age_seconds }`
  — `agent` is the affected agent (target of the spawn / config
  commit), not the asker. `description` is the manager's free-text
  blurb shown on the dashboard card. `commit_ref` is the
  kind-specific payload (see `docs/agent-lifecycle/approvals.md::Approval kinds
  (wire shapes)`).
- `Reminder { id, owner, message, due_at, age_seconds }` —
  `due_at` is the absolute time the scheduler is targeting (RFC
  3339 on the wire, see *Timestamps on the wire* below); clients
  compute time-until-fire against it.
- `PendingMessages { count }` — undelivered inbox messages the
  agent still owes itself a `recv` for. Informational + not
  cancellable (drain with `recv`); only emitted when `count > 0`,
  and surfaced first in the agent-flavour list as the most
  actionable signal. Counted host-side from the broker
  (`count_pending`), so it reflects what's genuinely still queued —
  the wake-message that drove the current turn is already delivered
  and not counted.
- `UnreadMatrix { rooms, summary }` — unread matrix notifications.
  Informational + not cancellable (clear with `mark_read`). Unlike
  the others this is injected by the in-container harness, not
  hive-c0re, because the matrix daemon lives inside the agent.

`age_seconds` saturates at zero on any clock anomaly (back-step,
unsynchronised wall clock, etc.) so the bulleted list never
shows nonsense ages.

`CancelLooseEnd { kind, id }` is the matching write surface. The
`kind` enum (`Reminder` / `Approval`) selects which underlying store
the dispatcher reaches into. `Reminder` cancels from either surface
subject to an ownership check (the scheduling agent).
`Approval` is manager-only — sub-agents don't submit approvals
so they have nothing of their own to withdraw; their wire
surface returns a clear error if they try. Cancelling an approval
transitions the row to `ApprovalStatus::Cancelled` and fires
`ApprovalResolved { status: "cancelled" }` so the dashboard pulls
the card out of the pending pane.

### Agent metadata

`AgentRequest::GetAgentMeta { name }` returns identity + status for
an agent. Self-introspection when `name = None` (replaces the older
`Whoami` request); target query when `name = Some`.

Response is `AgentMeta { name, running, hyperhive_rev,
status_text, status_set_at, hive_name, swarm_name, matrix_accounts }`:

- `hyperhive_rev`: `None` only when the configured flake URL has
  no canonical path. Otherwise carries the rev the target is
  currently pinned at.
- `running`: whether the target's container is currently up. When
  `false`, the host clears `status_text` / `status_set_at` —
  on-disk values from before the stop are stale snapshots and
  shouldn't be shown as live status. Defaults to `true` on the
  wire (older harnesses never serialised it, and the host only
  knew how to ask about live containers — keeps backwards-compat
  with pre-running-field payloads).
- `status_text` / `status_set_at`: last value written via
  `SetStatus`, plus its unix timestamp. Both `None` when the
  target has never set a status, when the agent name is unknown,
  or when `running = false` (see above).
- `hive_name` / `swarm_name`: display names read from
  `HYPERHIVE_HIVE_NAME` / `HYPERHIVE_SWARM_NAME` env (sourced from
  `services.hyperhive.hiveName` / `services.hyperhive.swarm.name`).
  Both `None` when the options aren't configured.
- `matrix_accounts`: one `MatrixIdentity` per configured + live matrix
  account the agent can act as. Empty for agents with no matrix
  provisioning.

### Timestamps on the wire

Timestamp fields that cross a JSON boundary (dashboard API + SSE,
the wire structs in hive-sh4re) serialize as **RFC 3339 UTC strings**
(`2026-07-02T18:30:00Z`) via `hive_sh4re::wire_time` — Rust keeps the
fields as `i64` unix seconds internally, only the JSON representation
changes, and deserialization leniently accepts both the string form
and the legacy bare integer (rolling-deploy skew, persisted blobs).
**Input-direction** fields agents compute as epoch (`first_fire_at_unix`,
schedule-edit `next_fire_at_unix`, `Wakeup::At`) stay integers. The
`*_unix` field *names* are kept for now — renaming is the wire-types
refactor's concern. The dashboard frontend parses via
`util.js::epochSec` wherever it needs arithmetic and feeds the string
straight to `new Date(s)` for display.

### HTTP error bodies

Every HTTP API in this repo answers failures with **RFC 9457
`application/problem+json`** (`{ type, title, status, detail }`), with the
human-readable cause in `detail`. An endpoint of ours returning a bare string
or a bespoke error shape is a **bug to file against the backend**, not
something for the caller to work around.

Use the `problem_details` crate (`features = ["axum"]`), which the daemons
already depend on: type a handler `Result<_, ProblemDetails>` and hand
`ProblemDetails::from_status_code(...).with_detail(...)` to `Err`.

The reason is the consumer, not tidiness. The UIs show errors through one
shared component with a copy button, so a caller has to know **which part of
the body is the message**. A bare string forces it to treat the whole payload
as prose, which is the difference between offering "copy the cause" and
dumping a response — and the cause is frequently the entire diagnosis (a
JetStream permission refusal, a TLS chain failure) rather than a summary.

Not in scope: the `hivectl` host-admin and in-agent unix sockets. Those are a
JSON-line protocol with their own result types; RFC 9457 is an HTTP format.

## Tool groups

The MCP tool surface an agent receives is derived from a set of named
`ToolGroup` values (`hive_sh4re::permissions::ToolGroup`), not from a hardcoded
binary flavor.

| Group | Tools |
|---|---|
| `messaging` | `send`, `recv`, `ack_until` |
| `meta` | `get_agent_meta` (`set_status` is always-on, see below) |
| `inbox` | `get_loose_ends`, `cancel_loose_end`, `remind` |
| `execution` | vestigial — `mcp__bash__run` / `mcp__bash__status` are always available unconditionally via `extraMcpServers`; this group's entries expand to non-existent `mcp__hyperhive__run` / `mcp__hyperhive__status` and have no effect. See `docs/tools/bash.md`. |
| `lifecycle` | `kill`, `start`, `restart`, `update`, `list_containers` *(privileged)* |
| `approvals` | `request_init_config`, `request_update_meta_inputs` *(privileged)* |
| `scheduling` | `request_schedule_prompt`, `fire_schedule_now`, `cancel_schedule`, `edit_schedule`, `list_schedules` *(privileged)* |
| `diagnostics` | `get_logs` *(privileged)* |
| `forge` | `create_repo` — create git repos through hive-c0re (operator-gated merge) |
| `web_tools` | none (gates the Claude built-ins `WebFetch`/`WebSearch`, not an MCP tool) |

**Always-on tools** — `set_status`, `compact`, and `mark_todos_done` are
exposed to every agent regardless of which groups it holds
(`ToolGroup::ALWAYS_ON_TOOLS`). The operator dashboard depends on every agent
being able to report its status chip, and the server-side `SetStatus` handler
has no tool-group check (only length validation), so gating it would only
desync the `--allowedTools` list from what the host actually accepts.
Revoking `meta` therefore drops `get_agent_meta` but never `set_status`.
`mark_todos_done` is here because todos are pushed to an agent independent of
whether it holds `inbox` — an agent without that group still needs a way to
clear them.

**Config storage** — per-agent tool groups live in
`/var/lib/hyperhive/meta/tool-groups.json` (hive-c0re-owned, committed to the
meta repo alongside `topology.json`). Format: `{ "alice": ["messaging", "meta",
"inbox", "lifecycle"], "bob": ["messaging", "meta", "inbox"] }`. An absent entry
means "use role default". Tool permissions are intentionally NOT configurable
from `agent.nix` — that file goes through the manager's approval flow, so
letting it declare its own groups would let the manager grant itself any tool by
submitting a config commit, bypassing the operator gate.

**Setting groups** — the operator sets groups via the dashboard or
`hive-c0re::tool_groups::set_groups(name, groups)`. After a change
`meta::sync_agents` commits the updated file; the next agent rebuild picks up
the new `HIVE_TOOL_GROUPS` env var. Agents with no entry get no var.

**Runtime resolution** — at session start the harness reads `HIVE_TOOL_GROUPS`
(a comma-separated list of snake_case group names injected by the meta renderer
from `tool-groups.json`). Unrecognised tokens are logged and skipped. Falls back
to `ToolGroup::AGENT_DEFAULT` (`messaging`, `meta`, `inbox`, `execution`) when
the var is absent or empty.

**Updating the surface** — when a new `#[tool]` fn is added to `AgentServer`
in `hive-agent-mcp/src/mcp/mod.rs`, add its name to the matching `ToolGroup::tools()`
slice in `hive-sh4re/src/permissions.rs`. That's the single source of truth;
`mcp_config::allowed_mcp_tools` (in `hive-agent/src/mcp_config.rs`) reads it at
session start.

## Capabilities

Capabilities gate system-level access that goes beyond the MCP tool surface —
things an agent can *access*, not just *call*. Parallel to tool groups but
orthogonal: an agent can have a tool group that registers a tool AND a capability
that allows the underlying resource access.

| Capability | Effect |
|---|---|
| `manage_root_agent` | may lifecycle-manage the root/manager agent via `kill`/`start`/`restart` |
| `read_host_journal` | `get_host_journal` MCP tool is registered + `GET /journal-host` requests are served |
| `query_agent_state` | may call `get_loose_ends` / `CountPendingReminders` targeting non-child agents |

**Config storage** — per-agent capabilities live in
`/var/lib/hyperhive/meta/capabilities.json` alongside `tool-groups.json`.
Format: `{ "atlas": ["read_host_journal"], "ruth": ["manage_root_agent"] }`.
An absent entry means "no extra capabilities". `render_flake` in `meta.rs`
reads this file and injects `HIVE_CAPABILITIES` (comma-separated
`snake_case` names) into each agent's systemd service env; absent entries emit
no env var so agents without capabilities don't trigger a spurious rebuild.

**Setting capabilities** — the operator sets capabilities via the
C4P4B1L1T13S section in the dashboard's P3RM1SS10NS tab.
`hive-c0re::capabilities::set_caps(name, caps)` is the write path.
After a change `meta::sync_agents` commits the updated file; the next agent
rebuild picks up the new `HIVE_CAPABILITIES` env var.

**Runtime resolution** — at session start the harness reads `HIVE_CAPABILITIES`
and resolves each token to a `Capability` variant. Unrecognised tokens are
logged and skipped. An absent or empty var means no extra capabilities.

**Capability NOT configurable from `agent.nix`** — same reasoning as tool
groups: an agent that could grant its own capabilities via a config commit would
bypass the operator approval gate.

**Adding a new capability** — add a variant to `Capability` in
`hive-sh4re/src/permissions.rs` + an arm to `as_str`. Add it to `Capability::ALL`
(the source of truth for the permissions UI columns). Implement the access
check in the relevant handler (`hive-c0re/src/socket_server/mod.rs`,
`hive-c0re/src/socket_server/lifecycle_handlers.rs`, `coordinator.rs`, or a
handler under `hive-c0re/src/dashboard/`).

## Async forms

Dashboard + per-agent mutating forms carry `data-async`; the shared
`bindAsyncForms` `submit` listener (`frontend/packages/shared/src/forms.js`,
imported as `@hive/shared/forms.js` and wired up from `tabs.js` on the
dashboard and `app.js` on the per-agent UI) intercepts, shows a spinner,
POSTs `application/x-www-form-urlencoded` (axum's `Form` extractor
rejects multipart), calls `refreshState()` on success. New mutating
forms should add `data-async` and optionally `data-confirm` (for a
JS-side `confirm()` prompt) or `data-prompt="…"` (for a
`window.prompt()` whose answer goes into a hidden input named by
`data-prompt-field`, default `note`).

`refreshState` defers automatically when `document.activeElement`
sits inside a managed section so the operator's typing isn't lost;
collapsible `<details data-restore-key=…>` survive the re-render
via `snapshotOpenDetails` / `restoreOpenDetails`.

## `rebuild` is the reconcile verb

`job_queue::templates::rebuild` builds the DAG that reconciles a
container to its wanted state: `write_dropins` (the nspawn-conf
rewrite — `PRIVATE_NETWORK=1`, `HOST_ADDRESS` = the bridge gateway IP,
sets `EXTRA_NSPAWN_FLAGS` — plus the systemd resource-limits drop-in)
is folded into the `Swap` node, then `nixos-container update` + stop +
start runs across the `StopForUpdate → Swap → RebuildBookkeeping`
brace and the tail `Reconcile` node. `flake.nix` itself is no longer
regenerated host-side on rebuild — it's tracked in the agent's
proposed/applied repos and rides along on every fetch (see
`docs/agent-lifecycle/approvals.md::Two repos per agent`).

Anything that changes per-container state on the host should be
re-applied here so a manual `↻ R3BU1LD` from the dashboard is
sufficient to recover.

## Actions are factored

`approve` / `deny` / `destroy` (and the lifecycle helper) live in
`actions.rs` / `hive-c0re/src/dashboard/`. The admin socket and the dashboard
POST handlers both call into them so the two surfaces never drift.

## Commit messages

Short, lowercase, no `Co-Authored-By` trailer. Imperative mood, no
period. Body explains *why* if non-obvious; otherwise the subject
alone is fine. Wrap at ~72 cols.

## Commit before test

Stage and commit when work *looks* ready, then run validation
(`cargo check`, `nix flake check`, real deploy). Failures get a
follow-up commit rather than an amend. The commit history is the
work log; rewriting it loses signal.

## Building & local checks

Build through the **flake devshell**, not a bare toolchain — agent
containers ship no global rust. `nix develop -c <cmd>` runs one
command inside the project-pinned env (cargo/clippy/rustfmt plus the
C compiler + `libsqlite3`/`ring` link deps); outside it a bare
`cargo build` fails with `failed to find tool "cc"` / `cannot find
-lsqlite3`. One command per invocation — agents run each task as a
fresh non-interactive process, so there's no persistent shell to
reuse.

```sh
nix develop -c cargo clippy --all-targets -- -D warnings
nix develop -c cargo test
nix fmt                       # treefmt — authoritative, NOT bare cargo fmt
```

`nix fmt` (treefmt) is the formatter CI gates on; bare `cargo fmt`
misses the non-rust files treefmt also covers, so always run `nix
fmt` before pushing.

**Clippy discipline — never add `#[allow(clippy::…)]`.** All lints are
CI-fatal at `-D warnings` (pedantic included); every warning that fires
must be *fixed*, not silenced. Common patterns:

- `too_many_lines` — extract a helper function or a sub-struct
  (the `TurnAccum` extraction in `stats.rs` is a worked example).
- `doc_markdown` (brand name without backticks in a doc comment) — add
  backticks: `` `DOMPurify` `` instead of `DOMPurify`.
- `must_use` / `unused_results` — actually handle or explicitly discard
  the return value (`let _ = …` is fine when intentional).

If a lint seems wrong for a specific call site, file an issue and ask
mara — don't add `#[allow]` speculatively. The gate is intentional.

**The devshell checks are not the full `nix flake check`.** Clippy /
fmt / `cargo test` cover most gates, but `nix flake check` runs extra
check derivations they don't:

- **`hivectl-docs`** regenerates `docs/tools/hivectl-cli.md` from
  hivectl's clap tree and **fails if the committed copy is stale**.
  So **after any change to a hivectl verb or flag, regenerate it**:
  ```sh
  nix develop -c cargo run --bin hivectl -- markdown-docs > docs/tools/hivectl-cli.md
  ```
  clippy / fmt / `cargo test` all pass *without* this — only the
  flake check catches the drift, and `ci-log` often can't show you
  why (it 500s on a fast failure), so you're left guessing "builder
  flake" when it's a stale doc.
- **`swarmctl-docs`** is the same check for `swarmctl` /
  `docs/tools/swarmctl-cli.md`:
  ```sh
  nix develop -c cargo run --bin swarmctl -- markdown-docs > docs/tools/swarmctl-cli.md
  ```
- there's also a flake `cargo-test` check and NixOS module
  evaluation in the set.

When local clippy/fmt/test pass but CI's `nix flake check` fails,
**don't assume a transient builder problem** — reproduce the real
gate locally: `nix flake check` (shares the build farm, use
sparingly) or build just the suspect check, e.g. `nix build
.#checks.x86_64-linux.hivectl-docs`.

## Best-effort oneshot services

The harness ships a family of one-shot systemd services that
configure agent-side surfaces from values hive-c0re writes into
the state dir at provisioning time:

- `tea-login` — writes `~/.config/tea/config.yml` from the
  `forge-token` written by `hive-c0re::forge::ensure_user_for`,
  so `tea repos create` / `tea pulls create` work without
  interactive prompts.
- `forge-avatar-sync` — uploads `hyperhive.icon` SVG to the
  agent's Forgejo profile, so the icon shows up on commits / PRs /
  issue comments.

(The matrix profile avatar is **not** a oneshot — `hive-matrix-daemon`
sets it over its live authenticated Client; see
`docs/agent-lifecycle/persistence.md::matrix avatar`.)

Shape contract — every one of these:

1. **Always `exit 0`**, even on internal failure. A non-zero exit
   would mark the unit `failed`, which in turn aborts
   `nixos-container update` and blocks rebuilds. The agent's
   capability surface is not allowed to gate the container
   build.
2. **No `set -e`** in the script body. Subshell failures must not
   propagate. Use `... || true` on every external call that can
   fail (forge unreachable, missing icon, parse error, etc.)
3. **Skip silently when prerequisites are missing**: no token
   file, no icon, no reachable upstream → `echo` a short skip
   line + `exit 0`. The next boot tries again.
4. **Wired to `multi-user.target`** so they run on every boot
   (lets a rotated token / new icon take effect without
   `systemctl restart` gymnastics).
5. **Re-runnable**: a second invocation produces the same final
   state (idempotent uploads, idempotent config rewrites). Used
   by the `.path` watchers that re-fire on token appearance (see
   `docs/agent-lifecycle/persistence.md::Matrix per-agent daemon`).

The artefact lives under the agent user's home where applicable
(`~/.config/tea/config.yml`) and is chown'd to that user, but the
service itself stays root-owned so the bootstrap ordering doesn't
need a user-existence check before each fire.

This pattern keeps the rebuild path resilient: any failure inside
these services degrades the corresponding surface (no tea config,
no avatar) but never blocks the container from coming up. The
operator notices through `journalctl -u <unit>` rather than a
broken switch-to-configuration.