hyperhive/docs/approvals.md

# Approvals + helper events

The approval queue is hyperhive's pivot: nothing that changes the
shape of an agent (its config, whether it exists) happens without an
operator click. The submitting agent — any agent with the `approvals`
tool group, which manages the config of its **direct children** (the
root agent for top-level agents; a sub-manager for its own subtree) — is
the policy gate in front of that queue; helper events are how it stays
informed about what happens after a decision lands.

## For operators

Every add/remove/change to an agent lands on your dashboard's Y3R
C4LL tab (or `hivectl approvals pending` / `approve <id>` from the
CLI) before it takes effect. What you'll see, and what to do with it:

- **Config change** (`MergeConfigPr`) — an agent proposed a change to
  another agent's config (or its own, via a sub-manager) as a forge
  pull request. Review the diff on the forge — the dashboard card
  links straight to it, same as reviewing any other PR. Approving
  triggers the deploy automatically: hive-c0re re-verifies the PR
  hasn't moved since you looked at it, evaluates it (a dry run,
  nothing applied yet), merges it, and rebuilds the container. If
  anything in that chain fails, the change rolls back automatically —
  the agent stays on its last-good config, no recovery action needed
  from you.
- **New agent** (`InitConfig` then `Spawn`) — creating a brand-new
  agent is two approvals. `InitConfig` creates the config repo and
  seeds it from a template; `Spawn` creates the container from that
  config. Tailoring the template first is not a separate mechanism —
  it's the config-change flow above, a PR you review like any other. Every later change goes through the config-change flow
  above — there's no repeat "spawn" for an existing agent.
- **Meta/flake update** (`UpdateMetaInputs`) — an agent asked to bump
  one or more Nix flake inputs (or all of them). Approving runs the
  update and commits the lock change; it doesn't rebuild anything by
  itself.
- **Scheduled prompt** (`SchedulePrompt`) — an agent asked to schedule
  a message to one or more inboxes at a future time. You can also add
  schedules yourself directly from the SCH3DUL3S tab, which skips this
  approval step entirely — the gate here is specifically for an
  *agent* asking to schedule something, not for you doing it.

Don't want to approve something? **Deny it** (`DENY` on the dashboard
card, or `hivectl approvals deny <id>`) — nothing runs. Either way the
submitting agent is always notified their request was denied; what's
optional is only the reason text, which you can add on the dashboard's
prompt (cancelling that prompt aborts the whole deny, not just the
reason) but not from the CLI. Denying is final: a denied approval
can't be re-approved later, the agent has to submit a fresh one (a new
PR, a new request).

Everything below this point is the implementation detail behind that
flow.

## End-to-end approval flow

Config changes flow through a **forge pull request** on the agent's
`agent-configs/<name>` repo — the same surface agents use for code PRs.
There is no bespoke MCP tool for config changes: opening the PR IS the
request.

1. The submitting agent (the child's parent, holding the `approvals`
   tool group) **clones** `agent-configs/<name>`, edits it there (any
   tracked path, but `agent.nix` is the contract entry point), commits
   with its own git identity, and pushes a branch + opens a PR with
   `hive-forge` — the same way it would change any other repo.
   The bind-mounted `/agents/<name>/config/` is a **copy for reading** a
   config, not the tree to edit: authoring in place there produces no PR
   and no approval. (It is currently mounted read-write, which is a
   defect tracked separately, not an authoring path.)
   Branch protection (push/merge whitelist = `core`, approvals whitelist
   = operator team; see "Forge mirror" and #1787) makes the agent a
   write collaborator that **cannot merge its own config PR**.
2. hive-c0re's `/webhook/config-pr` endpoint receives the Forgejo
   `pull_request` event (opened / synchronized / reopened) and queues a
   `MergeConfigPr` approval; a poll fallback catches any missed webhook.
   The approval row stores the PR **number** (`commit_ref`) and the PR
   **head sha at queue time** (`fetched_sha` — the "reviewed" sha). If
   the PR head later moves, the stale approval is superseded by a fresh
   one pinned to the new head, so the operator always reviews what will
   actually deploy.
3. The operator reviews the PR **on the forge** (native diff, threaded
   comments, CI status) and sees a matching card on the dashboard with a
   "review PR on forge" deep link. They click ◆ APPR0VE (or
   `hivectl approvals approve <id>` on the CLI) once satisfied.
4. On approve, a deploy DAG runs three phases under a resource-holding
   `DeployWindow` root (see *Queue templates* below):
   - `MergeVerify` re-reads the live PR head and **aborts if it drifted**
     from the reviewed `fetched_sha` (the submitter must push again,
     which queues a fresh approval); then fetches that head into the
     applied repo and **eval-verifies** it — a flake eval on a throwaway
     checkout. This is the trust gate: it relies on c0re's own eval, not
     on any in-repo (agent-forgeable) signal like a CI status. Nothing is
     mutated in this phase, so a rejection here leaves the forge and the
     applied repo exactly as they were.
   - `DeployApply` parks the pre-merge `applied/main` in
     `refs/hyperhive/rollback/<approval-id>`, then fast-forward-merges
     the reviewed head to the forge config repo's `main` (this IS the
     merge — a `core`-authenticated ff-merge pinned to the reviewed sha,
     so a moved PR head can't substitute bytes), and runs the deploy
     proper (`deploy_applied_target`): ff `applied/main`, two-phase meta
     deploy, container rebuild. On success it drops the rollback ref and
     plants `deployed/<id>`.
   - `DeployTail` runs on **every** outcome, including a cancel-cascade.
     If the rollback ref survived, the deploy never confirmed good: it
     rolls `applied/main` back, resyncs the working tree, and aborts the
     staged meta lock, so the agent stays on its last-good tree. Then it
     mirrors the config repo (and its new deploy tag) to the forge.

   The rollback state lives in a **git ref, not a local variable**, on
   purpose: hive-c0re can restart between the apply and the tail, and the
   tail still has to know what to undo when it does.
5. `HelperEvent::ApprovalResolved` (and `Rebuilt`) land in the
   **submitting agent's** inbox via `notify_submitter`, carrying both the
   canonical sha and the terminal tag (the approval row carries a
   `submitter` column recording the agent the change is for).

### Withdrawing a pending approval

The submitting agent can call `cancel_loose_end(kind: "approval", id)` to
withdraw an approval that hasn't been acted on yet.
The row transitions to `ApprovalStatus::Cancelled` (distinct from
`Denied`/`Failed`), the dashboard pulls the card out of the
pending pane, and `ApprovalResolved { status: "cancelled" }` fires
on the root agent + dashboard channels. Approvals that have already
been approved/denied/failed return an error — the resolution is
final once the operator (or a lifecycle failure) acted on the row.

The socket refuses the `approval` kind with a clear error for any
agent that lacks the `approvals` tool group: only an agent with that
group submits approvals (for its direct children), so an agent
without it has nothing of its own to withdraw.

`InitConfig` approvals create a brand-new agent's config repo. On
approve, hive-c0re seeds it with a default `agent.nix` template and
pushes a todo (`push_todo_submitter`) into the submitting agent's
in-container store. The operator then **spawns** the agent (the
`Spawn` approval / `◆ R3QU3ST SP4WN` button), which creates the
container from that config.

Changing what the template seeded is not a special case: like every
later change, it's a PR on that config repo (`MergeConfigPr`), made
from a clone, reviewed and approved by the operator. The PR flow is
the one path — an operator can equally drive both steps herself
through the web UI or the forge.

### Approval kinds (wire shapes)

`ApprovalKind` carries five variants; each maps to a different
`commit_ref` encoding because that field is overloaded as the
kind-specific payload carrier.

- `MergeConfigPr` — the config-change flow. Triggered automatically:
  when an agent opens (or force-pushes) a PR on its
  `agent-configs/<agent>` forge repo, hive-c0re's `/webhook/config-pr`
  endpoint receives the Forgejo pull_request event and queues this
  approval row. No MCP tool call needed — the forge PR IS the request.
  `commit_ref` stores the **PR number** (decimal), and `fetched_sha` is
  the PR **head sha at queue time** (the "reviewed" sha). On approve,
  the deploy DAG's `MergeVerify` phase re-reads the live PR head and
  aborts if it drifted from `fetched_sha` (submitter must push again to
  re-trigger), then fetches that head into the applied repo and
  eval-verifies it; `DeployApply` fast-forward-merges the forge config
  repo's `main` to it (the merge) and runs `deploy_applied_target`;
  `DeployTail` compensates on failure. Never a first spawn.
- `Spawn` — direct container creation from the agent's config repo.
  `commit_ref` is empty. Submitted via `HostRequest::RequestSpawn`
  (operator-gated, the `◆ R3QU3ST SP4WN` dashboard button +
  `hivectl agent <name> request-create` CLI). The host-level `HostRequest::Spawn`
  variant bypasses the approval queue entirely — privileged-context use
  only (operator on the host shell, test scripts, one-off recoveries;
  `hivectl agent <name> create`). This is the **canonical first-spawn**: a new agent's `InitConfig`
  seeds its config repo, the submitting agent customises it, then the
  operator spawns to create the container. Subsequent config changes go
  through a `MergeConfigPr` PR.
- `InitConfig` — `commit_ref` is empty; the variant just gates
  "seed the proposed repo with the default template" against
  operator approval. Step 1 of the two-step spawn flow above.
- `UpdateMetaInputs` — `commit_ref` stores the JSON-encoded inputs
  array (`"[]"` = all inputs, `"[\"nixpkgs\"]"` = just nixpkgs,
  etc.). `agent` field is set to the requesting root agent.
  On approve hive-c0re runs `nix flake update [inputs...]` on the
  meta flake and commits the resulting lock changes.
- `SchedulePrompt` — `commit_ref` stores the JSON-encoded
  `SchedulePromptPayload` (target list, body, schedule) so the
  approval row carries the full submission verbatim. On approve
  hive-c0re inserts a row into `scheduled_prompts` with
  `source = approval:<id>`; the worker fans the body out as
  inbox messages to each target at the scheduled time, recurring
  when `interval_seconds` is set.

### Scheduled prompts (submit paths)

Two ways a row lands in `scheduled_prompts`:

- **Operator-direct** (`source = "operator"`): the operator adds a schedule through the dashboard form. Lands in the table immediately, no approval gate — operator action is already the trust boundary.
- **Agent-requested** (`source = "approval:<id>"`): an agent submits a `RequestSchedulePrompt` through its MCP socket (the `request_schedule_prompt` tool, `scheduling` group). An `ApprovalKind::SchedulePrompt` row is queued; on approve, hive-c0re inserts the schedule row with `source = approval:<id>` so the audit trail points back at the operator decision (above).

No self-target shortcut: even agent-self schedules need approval. The existing `remind` MCP tool stays the quick self-wake path (no approval, lands directly in the agent's own inbox); this module is the bigger, multi-recipient, operator-visible thing.

### Scheduled prompt worker (catch-up clamp)

When hive-c0re comes back from being down, the worker sees rows whose `next_fire_at_unix` is well in the past. For recurring rows that would mean firing N delayed pulses in a row — spammy and useless. Instead the worker fires **once** per row and bumps `next_fire_at_unix` to the next interval slot ≥ `now`, recording how many cycles were skipped in `last_result` (per-target). Operators see "fired late, caught up from 17 skipped" instead of 17 wake-up storms.

One-shot rows fire once (if past due, on the next worker pass) and are deleted by the worker; recurring rows survive until cancelled.

`targets` is its own table (`scheduled_prompt_targets`) so partial cancellation flips a single row and the dashboard can show last-fired / last-result per recipient. Cancelling every target reaps the parent row on the next worker pass.

### Scheduled prompt delivery: todo, not a broker message

An agent target's delivery is `push_todo` (`Coordinator::push_todo`,
`docs/coordinator.md` covers the mechanism generally), not a broker
`Message` — a scheduled prompt wakes its target with a todo instead of
driving an immediate turn, by design. `key = "schedule:<id>"` per
target drives `push_todo`'s own upsert-by-key dedup: a re-fire of the
*same schedule* against a target that hasn't reviewed the last one
collapses into that one todo instead of stacking up.

**`operator` is the one exception** — it's a valid schedule target but
has no in-container todo inbox, so it keeps the original broker
`Message` path (the dashboard mirrors `to == operator` into its own
pane, same as before).

### Missing-target failure

When a target name doesn't resolve to a known agent (container
destroyed, operator typo, etc.) the worker:

1. Records `last_result = "no such agent: <name>"` on the
   per-target row.
2. Sends a single advisory `Message` from `system` to `operator`
   naming the schedule, target, and reason. This one stays a `Message`
   regardless of target type — it's a to-operator advisory about a
   broken schedule, not the schedule's own delivery.
3. Continues fanning out to the other live targets.

Transient broker errors (sqlite lock contention, etc.) get the same
`last_result` annotation plus a `tracing::warn`, and then:

- **Recurring rows** re-arm to the next interval slot — the retry
  self-heals on the next worker pass.
- **One-shot rows** are deleted unconditionally after their single
  fan-out pass; a broker error on a one-shot is not retried (the
  operator advisory and `last_result` are the only audit trail).

### Reminder delivery: file-path semantics

A reminder may carry a `file_path` (the agent-visible path inside its
container, e.g. `/agents/<name>/state/foo.md`). On delivery hive-c0re:

1. **Translates** the container path to the host path
   (`/var/lib/hyperhive/agents/<name>/state/foo.md`) so c0re can write
   from outside the container.
2. **Validates** the path: rejects anything outside the agent's own state
   subtree, containing `..` (path traversal), or with an empty relative
   tail. On rejection the write is skipped and the original message is
   delivered inline with a warning — the reminder still fires.
3. **Defends against symlink escape**: after `create_dir_all`, the parent
   dir is canonicalized and re-verified to live under the agent's host
   state root. The final file is opened with
   `O_NOFOLLOW | O_CREAT | O_TRUNC` so an existing symlink at the
   basename cannot redirect the write to an arbitrary host path.
4. **Writes the body to disk** and delivers a short pointer message in its
   place, keeping the agent's inbox / wake-prompt small while the bulky
   payload is read out of band.

Atomicity of the inbox INSERT + `reminders.sent_at` UPDATE is handled
inside `Broker::deliver_reminders_batch`; the scheduler only computes the
body strings before calling it.

### Destroy semantics

`HostRequest::Destroy { name, purge }` is the lifecycle tear-down,
not an approval. Stops + removes the nspawn container, drops the
systemd drop-in, fails any pending approvals. Persistent state
(proposed/applied repos, claude credentials, `/state/` notes) is
**kept by default** — recreating the agent with the same name
reuses prior config + login. With `purge = true` the agent's
`/var/lib/hyperhive/{agents,applied}/<name>/` trees are also
wiped (config history + creds + notes gone forever). The
root/bootstrap container is destroyable like any other — hive-c0re
recreates it on the next startup if it's absent, so destroying it is
transient.

## Meta flake

The hive-c0re-owned repo at `/var/lib/hyperhive/meta/`
declares one flake input per agent (`agent-<n>.url =
"git+http://<forge>/agent-configs/<n>.git"`) and one
`nixosConfigurations.<n>` output per agent. Each output wraps
`inputs.agent-<n>.nixosModules.default` with the identity +
`HIVE_PORT` / `HIVE_LABEL` / `HIVE_DASHBOARD_PORT` injection module.
Containers run against `--flake /var/lib/hyperhive/meta#<n>`.

The declared input url is the agent's **forge config repo** (the
same `agent-configs/<n>` the config-PR flow lands approved changes
on), so the meta flake references a reviewable, reproducible source
rather than a local checkout. hive-c0re authenticates that
`git+http` fetch via a git credential helper that reads the live
forge-core token — no token in the url or the lock. The deploy and
manual-rebuild paths, however, do **not** re-lock from the forge:
they `--override-input agent-<n>
git+file:///var/lib/hyperhive/applied/<n>`, locking the exact config
that `verify_commit` gated and `applied/<n>/main` was
fast-forwarded to. That keeps a deploy/rebuild reproducible and
independent of forge reachability — rebuilds fire on crash-restart
and meta bumps, not just config PRs — while the declared url stays
the forge. `sync_agents` re-renders + re-locks the persistent input;
a plain `nix flake lock` leaves an existing applied override in
place (it only re-locks when the declared url itself changes), so
the forge-declared / applied-deployed split is stable.

Per-deploy lock flow (two-phase), spread across the deploy subtree's
nodes — each phase is its own node, so the queue can show which one is
running and a restart resumes at node granularity:

1. `DeployApply` → `meta::prepare_deploy(name)` runs
   `nix flake lock --update-input agent-<n>` without
   committing. Working tree of meta now points the input at
   `applied/<n>/main` (which the deploy already fast-forwarded to
   the reviewed PR head).
2. The rebuild subgraph `DeployApply` grows into the DAG builds and
   swaps the container (`AgentWindow` bracing `Prebuild → StopForUpdate
   → Swap → RebuildBookkeeping`, plus `Reconcile`). Nix evaluates
   against the staged lock.
3. On success — `FinalizeDeploy` drops the rollback ref, plants
   `deployed/<id>`, then `meta::finalize_deploy(name, sha, "deployed/
   <id>")` stages `flake.lock` and commits with
   `deploy <n> deployed/<id> <sha12>`. Meta's git log gains
   one entry per successful deploy.
4. On failure — the `DeployTail` node runs `meta::abort_deploy()`
   (`git restore flake.lock`) so the meta history shows only
   successes; the failure stays as an annotated `failed/<id>`
   tag in `applied/<n>`. The tail runs on every outcome, so this
   also covers a hive-c0re restart mid-build: the staged lock is
   dropped and `applied/main` rolled back from the parked
   `refs/hyperhive/rollback/<id>`.

Single-phase variants exist for paths without
rollback semantics: `meta::lock_update_for_rebuild(name)` for
the manual `↻ R3BU1LD` button (commits if the lock changed)
and `meta::lock_update_hyperhive()` for the
auto-update flake-rev bump (one shot before per-agent
rebuilds, commits if the lock changed).

`meta::sync_agents(hyperhive_flake, dashboard_port, &agents)`
is the idempotent reconciler called by `spawn`, `destroy`,
`rebuild`, and the startup migration. Renders `flake.nix`
from the agent list; if it differs from disk, runs
`nix flake lock` + commits as `regenerate meta flake` (or
`seed meta from N agent(s)` on the very first call).

The root agent has `/meta` RO-bound inside its container:
`git -C /meta log --oneline` is the swarm-wide deploy log,
`cat /meta/flake.lock | jq '.nodes["agent-<n>"].locked'`
resolves which sha each agent is pinned at right now.
Dashboard surfaces the same info as a `deployed:<sha12>` chip
per container row.

## Two repos per agent

```
/var/lib/hyperhive/agents/<name>/config/    proposed — parent mount is RO
└── <anything>                              # any files the submitting
                                            # agent wants in the commit.
                                            # agent.nix is the
                                            # convention entry
                                            # point; flake.nix is
                                            # tracked boilerplate
                                            # (submitting agent doesn't
                                            # edit it).

/var/lib/hyperhive/applied/<name>/          applied — core-only
├── .git/                                   # tag-rich history
├── flake.nix                               # tracked, fixed
│                                           # boilerplate exporting
│                                           # nixosModules.default
├── agent.nix                               # working tree of main
└── <other committed files>                 # also tracked

/var/lib/hyperhive/meta/                    swarm-wide flake — core
├── .git/                                   # one commit per successful
│                                           # deploy
├── flake.nix                               # generated from agent set
└── flake.lock                              # pins each agent's sha
```

Why two physical repos: the submitting agent's `/agents/<n>/config/` is
RW — a buggy or hostile agent can `git clean -fdx` its own
proposed tree. The applied repo is never bind-mounted (except
the read-only `.git` exposure described below) so a destructive
move inside the container cannot reach it.

The container's `--flake` ref is `/var/lib/hyperhive/meta#<name>`
(see "Meta flake" above). The agent's own `applied/<n>/flake.nix`
is a fixed boilerplate that exports `nixosModules.default =
import ./agent.nix`; the meta flake imports that module and
wraps it with identity + `HIVE_PORT` / `HIVE_LABEL` /
`HIVE_DASHBOARD_PORT`.

### Tag state machine

Each deploy leaves a tag on the underlying commit inside the applied
repo:

| Tag | When | Annotated? |
|---|---|---|
| `deployed/<id>` | rebuild succeeded — `main` ff's here | no |
| `failed/<id>` | rebuild failed | yes (body = error) |

`deployed/0` is planted at first spawn. `applied/main` is always the
latest `deployed/*`. A `failed/` tree stays browsable forever — `git log
--tags` in the applied repo is the audit trail. A denied or failed config
PR carries no extra state on the forge side: the PR stays open, and the
submitter pushes again (or closes it) to retry.

### Dispatch via the job queue

Long-running approval work — `MergeConfigPr`, `UpdateMetaInputs`,
`Spawn` — runs as a DAG on the global job queue
(`docs/coordinator.md::Job queue`), submitted by the approval handler
rather than run inline:

| `ApprovalKind` | DAG submitted | source |
|---|---|---|
| `MergeConfigPr` | `rebuild` (`DeployWindow` root + `MergeVerify → DeployApply` + `DeployTail`) | `approval` |
| `UpdateMetaInputs` | `meta_update` (`MetaLock` + rebuild fan-out) | `approval` |
| `Spawn` | `spawn` (`Create → WriteDropin → Reconcile`) | `approval` |
| `InitConfig` | — runs inline (sub-second git seed) | — |
| `SchedulePrompt` | — runs inline (single sqlite insert) | — |

The DAG carries the originating `approval_id`, surfaced on the node that
owns it — for a deploy that's the `DeployWindow` root, so the dashboard
renders one approval card, not four. **Every** queued kind resolves
through `actions::resolve_approval_dag` when its DAG settles terminal:
the deploy's phases are ordinary queue nodes, so the DAG's own terminal
state is the authoritative outcome. That hook fires the matching
`HelperEvent::*` via `finish_approval`, derives the `Rebuilt` event's
terminal tag (verifying the tag actually resolves in the applied repo —
a pre-merge rejection plants none), posts the failing build log back to
the config PR, and for a spawn runs the post-spawn forge bookkeeping.

Two visible consequences:

- **Operator dashboard**: after clicking APPR0VE the work-in-progress
  shows up on the *rebuild queue* card (`GET /api/jobq/graph`, refetched
  on every `rebuild_queue_changed` tick), not on the approvals panel
  (which already moved the row to "approved"). A long meta-update
  cascade renders as a parent DAG with one child rebuild per affected
  agent — see `docs/web-ui.md` for the layout.
- **Cancellation**: the dashboard's *× cancel* button on a still-queued
  DAG calls `POST /api/rebuild-queue/{id}/cancel`, which flips it to
  `Cancelled` before any node runs (and fails the approval row instead
  of leaving it dangling). Returns `{"cancelled": true}` on success,
  `{"cancelled": false}` once any node started — terminal states can't
  be retroactively rewritten.

The `approval` source + `approval_id` mean a tail-end build failure
surfaces back as a failed approval row, not just a silent queue
entry. `manual` (dashboard ↻ R3BU1LD) and `auto_update` (boot
reconcile) DAGs use the same queue but skip the approval plumbing.

### Forge mirror

The bundled `hive-forge` container is mandatory (it deploys with
hyperhive), and hive-c0re mirrors every agent's applied repo into a
private `agent-configs` Forgejo org. `forge::push_config(<name>)` pushes `applied/main` plus
every tag to `agent-configs/<name>` after each ref mutation:
the spawn that seeds `deployed/0`, every successful deploy (which
plants `deployed/<id>`) or failed build (`failed/<id>`), and a
sweep at startup. Pushes are best-effort — a missing or stopped
forge never blocks a deploy.

Each agent is a **write collaborator on its own** `agent-configs/<name>`
repo — so it can push a branch and open a config PR — but not a member
of any other agent's, so it can't reach another agent's config through
the forge. Branch protection keeps `main` push/merge `core`-only with
operator-team approval, so an agent can't fast-forward its own config or
self-merge its PR (see the End-to-end flow + #1787). The tokenised push
URL is passed inline to `git push`, never written into
`applied/<n>/.git/config`; that repo is RO-bind-mounted into the root
agent, and a stored token would leak core's admin credential to an
agent.

The dashboard deep-links into this org — a `config repo` link
per container row and a `review PR on forge` link per config-PR
approval card. See `docs/web-ui.md`.

### Submitting agent's view of config repos

Every parent agent's container has its **direct children's** config
repos bind-mounted **read-only** (topology-driven: `lifecycle.rs` calls
`bind_child_agent_dirs` for each entry in
`topology::children_of(agent_name)`). It is a copy to *read* a child's
current config — not an editing surface.

An agent with the `approvals` tool group submits a change the same way
any other change is made: **clone the child's config repo from the
forge into its own state dir, commit on a branch, open a PR**, and let
the operator review and approve it. There is deliberately no second,
mount-shaped path that reaches the same file without the review.

Agents holding the `can_manage_top_level_agents` topology role (see
`hive-c0re/src/agent_config/topology.rs`) get additional host-side
bind mounts via `set_nspawn_flags`:

- `/var/lib/hyperhive/agents/` → `/agents/` (RW) — all top-level
  agents' proposed repos (not just direct children).
- `/var/lib/hyperhive/applied/` → `/applied/` (RO) — every agent's
  authoritative applied repo, including `.git`.
- `/var/lib/hyperhive/meta/` → `/meta/` (RO) — the swarm-wide
  deploy flake.

The root agent holds this role; a sub-manager that only manages a
subtree does not, and only has its direct children's config dirs.

Each proposed repo (`/agents/<n>/config/`) is pre-configured
with `applied` as a git remote pointing at
`/applied/<n>/.git`. Useful incantations from inside an agent with
the full `/applied` mount:

```sh
git -C /agents/<n>/config fetch applied
git -C /agents/<n>/config log applied/main --oneline
git -C /agents/<n>/config show applied/refs/tags/deployed/<id>
git -C /agents/<n>/config show applied/refs/tags/failed/<id>   # body = build error
git -C /agents/<n>/config show applied/refs/tags/denied/<id>   # body = operator note
git -C /agents/<n>/config rebase applied/main                 # base in-flight work on what's deployed

git -C /meta log --oneline                                    # swarm-wide deploy history
cat /meta/flake.lock | jq '.nodes | with_entries(select(.key | startswith("agent-")))'
```

The RO binds block push at the kernel level — git plumbing inside the
container cannot corrupt either authoritative repo.

## Startup migrations (older hosts)

hive-c0re runs a couple of idempotent migrations on every startup so a
host set up before the tag-driven-deploy + meta-flake scheme (both
described above) converges to it automatically. Each phase is a no-op
once already applied:

- **Tags**: agents from before the tag-driven scheme are tagged
  `deployed/0` on `main` once. Non-destructive — it doesn't touch live
  containers, state dirs, or claude creds.
- **Meta flake**: rewrites each `applied/<n>/flake.nix` to the
  module-only boilerplate, wires the `applied` remote in each proposed
  repo, and bootstraps the meta repo from the current agent list. Set
  `HIVE_SKIP_META_MIGRATION=1` on the service to defer this phase.

No state loss in either migration: claude creds, `/state/` notes, the
events DB, and both proposed + applied history all survive. The root
agent keeps its session; sub-agents stay logged in.

## The root/bootstrap container is hive-c0re-managed

The root agent container runs through the **same lifecycle as
sub-agents**. On `hive-c0re serve` startup, if `ruth` is missing,
hive-c0re creates it. The root agent's flake lives at
`/var/lib/hyperhive/applied/ruth/`; its proposed config at
`/var/lib/hyperhive/agents/ruth/config/`. The root agent can edit its own
`agent.nix` (visible inside the container at `/agents/ruth/config/`)
and open a config PR on `agent-configs/ruth` for operator approval,
same as any other agent.

Differences from sub-agents:

- `flake.nix` extends `hyperhive.nixosConfigurations.manager`
  (vs `agent-base`).
- Web UI port via `lifecycle::agent_web_port("ruth")` — same
  FNV-1a hash as every other agent (8100..8999 range).
- `set_nspawn_flags` adds two extra binds: `/var/lib/hyperhive/agents`
  → `/agents` (RW) so the root agent can edit per-agent proposed repos,
  and `/var/lib/hyperhive/applied` → `/applied` (RO) so the root agent
  can `git fetch` deployed/failed/denied tags from any agent's
  authoritative applied repo (see "Root-agent view of applied" below).
- First-deploy spawn bypasses the approval queue (the root agent is
  required infrastructure).
- Per-agent socket lives at `/run/hyperhive/manager/`, owned by
  `manager_server::start`.

**Migration note** (for older hosts): drop any `containers.root =
{ ... }` block from your host NixOS config. hyperhive creates and
updates the root agent itself.

## Root-agent policy

The system prompt (`hive-agent/prompts/system.md`, rendered by
`hive-agent/src/prompt.rs`) is the **same for every agent**; what
varies is which MCP tools are surfaced (gated by tool groups and
capabilities in `agent.nix`). There is no `role:manager` block that
renders only for the root agent. The root agent's approval-gating
behaviour comes from its CLAUDE.md / agent-specific instructions, not
the system prompt template.

Any agent (root or not) can also ask a structured question of the
operator or a peer agent via the `ask`/`answer` MCP tools, independent
of the approval flow above — see
`docs/conventions.md#question-routing-ask--answer` for the routing
rules, `ttl_seconds` expiry, and cancellation.

## Helper events to the submitting agent

`Coordinator::notify_submitter(approval_id, &HelperEvent)` routes the
event to the agent that originally submitted the approval (looked up from
the `submitter` column on the `approvals` table). The harness delivers it
as a regular `system` inbox message so it drives a normal claude turn. A
"FYI, check when convenient" event doesn't need a message — those go
through `Coordinator::push_todo`/`push_todo_submitter` instead, a direct
live dial of the target agent's in-container todo socket (same
`UpsertTodo` request in-container producers use); the `Spawn` approval
uses this path, not a `HelperEvent`. Legacy approval rows that predate the
submitter column fall back to the
root agent. Variants (`hive_sh4re::manager::HelperEvent`):

- `ApprovalResolved { id, agent, commit_ref, status, note }` —
  fired by `actions::approve` + `actions::deny` whenever an
  approval transitions to its terminal state.
- `ContainerCrash { agent, note }` — `crash_watch`: a previously-
  running container went away with no operator-initiated transient
  state (Stopping / Restarting / Destroying / Rebuilding) AND no
  such transient was cleared in the last 30s (`RECENT_TRANSIENT_GRACE`
  tombstone, three `POLL_INTERVAL`s — closes the race where a
  lifecycle op finishes between two crash-watch polls and the
  container shows briefly as "stopped without transient" before
  the next start). The root agent can `start` it again or escalate.
- `NeedsUpdate { agent }` — sub-agent's recorded flake rev is
  stale. The root agent calls `update(name)` to rebuild — idempotent,
  no approval required.
- `QuestionAnswered { id, question, answer, answerer }` —
  dashboard `/answer-question/{id}` (answerer = `"operator"`),
  peer `Answer` request (answerer = agent name), or ttl watchdog
  expiry (answerer = `"ttl-watchdog"`, answer = `"[expired]"`).
- `QuestionAsked { id, asker, question, options, multi }` —
  fired when an agent calls `Ask { to: Some(<this-agent>), ... }`.
  The recipient responds via `Answer { id, answer }` and the
  asker sees the matching `QuestionAnswered`.

The remaining lower-urgency lifecycle notices — `Rebuilt`, `Killed`,
`Destroyed`, `NeedsLogin`, `LoggedIn`, `ConfigReady` — are "FYI, check
when convenient" events with no reason to drive an immediate turn, so
they deliver via `push_todo`/`push_todo_submitter` (see above) instead
of `HelperEvent`: an `agent_todo_socket` push instead of a broker
message, `subsystem = "core"`, `key = "<event>:<agent>"` for dedup,
and a single free-text `summary` (`rebuilt_todo_summary` renders
`Rebuilt`'s `ok`/`note`/`sha`/`tag` fields into that string).

Optional `sha` field on `ApprovalResolved` carries the canonical
hive-c0re-vouched commit sha. Optional `tag` carries the deploy
bookkeeping tag — `deployed/<id>` on a successful build or
`failed/<id>` on a failed one, planted by the `MergeConfigPr` deploy.
Both fields are `Option`: `None` on the paths that don't deploy a new
commit (spawn / init_config / meta-update / deny, and
`auto_update::rebuild_agent` reapplying the existing main, or the
dashboard `↻ R3BU1LD` button when the lock didn't move). When set,
`git show <sha>` against `/agents/<n>/applied.git` inside the
bootstrap container yields the exact tree that was referenced.

To add a new lifecycle notice: if it needs to drive an immediate turn
(a live conversation like `Ask`/`Answer`, or something genuinely
urgent), add a `HelperEvent` variant + call sites + update
`prompts/system.md`'s message-event list. If it's "FYI, check when
convenient," call `push_todo`/`push_todo_submitter` directly instead —
no new wire type needed.

## Auto-update on startup

`hive-c0re serve` runs `auto_update::run` in a background task right
after opening the coordinator. It enumerates managed containers and
rebuilds any whose recorded hyperhive rev differs from the current
one — sub-agents and the root agent go through the same `lifecycle::rebuild`
path.

"Rev" = canonical filesystem path of `cfg.hyperhiveFlake`. Marker
file: `/var/lib/hyperhive/applied/.<name>.hyperhive-rev`. If the
flake input has no canonical path (e.g. a `github:` URL),
auto-update is a no-op — rebuild manually.

The dashboard surfaces pending updates per agent: a clickable
"needs update ↻" badge appears whenever the marker differs from
current rev. The badge POSTs `/api/rebuild/<name>`, calling the same
`auto_update::rebuild_agent` path so manual triggers and the
startup scan can't drift. When at least one container is stale, a
top-level `↻ UPD4TE 4LL` button appears that loops over every
stale container.