# Persistence + retention

Where state lives, what survives what, and how it's bounded.

## Three sqlite databases

### `/var/lib/hyperhive/db/broker.sqlite` (host)

Six tables, all in one file — four queues plus the schedule
header/targets split:

- `messages` — every inter-agent / operator-bound message.
  `sender / recipient / body / sent_at / delivered_at / acked_at /
  in_reply_to`. `in_reply_to` links a reply to its parent row id;
  the dashboard and per-agent inbox render these as threaded rows.
- `reminders` — `mcp__hyperhive__remind` queue.
  `agent / message / file_path / due_at / created_at / sent_at /
  attempt_count / last_error`. `file_path` set when a body
  exceeded the inline soft-cap and got auto-spilled to a file
  under the agent's state dir; the worker delivers a short
  pointer instead. `attempt_count` / `last_error` accumulate
  on delivery-failed retries.
- `approvals` — the queue. `agent / kind (apply_commit | spawn |
  init_config | update_meta_inputs | schedule_prompt) /
  commit_ref / requested_at / status / resolved_at / note`.
- `operator_questions` — `ask` / `answer` queue (despite the
  table name, stores both operator-targeted + agent-to-agent
  questions since the `ask` rename).
  `asker / question / options_json / multi / asked_at /
  deadline_at (ttl) / answered_at / answer / target`. `target IS
  NULL` = operator path (dashboard); `target = '<agent>'` = peer
  Q&A (`HelperEvent::QuestionAsked` pushed into target's inbox,
  answered via `Answer` request). Migrated via `ALTER TABLE ADD
  COLUMN` against `pragma_table_info`.
- `scheduled_prompts` — recurring + one-shot prompt queue.
  `owner / body / interval_seconds (NULL = one-shot) /
  next_fire_at_unix / created_at_unix / source ("operator" or
  "approval:<id>") / cancelled_at_unix / description`. `owner`
  drives cancel-permission checks (operator vs the submitting
  agent). Cancelled rows are tombstoned and reaped by the worker
  on its next pass.
- `scheduled_prompt_targets` — per-target state for each schedule.
  `schedule_id / target / cancelled_at_unix /
  last_fired_at_unix / last_result`. `ON DELETE CASCADE` from
  `scheduled_prompts(id)` — requires `PRAGMA foreign_keys = ON`
  per connection (set at open).

Retention:

- `Broker::vacuum_delivered` runs hourly via a tokio task in
  `hive-c0re::main`. Drops acked message rows older than 30 days
  (`acked_at IS NOT NULL`). Undelivered + delivered-but-not-acked
  rows are always kept — the harness `ack_turn`s only after a
  successful turn, so an unacked row can still be requeued via
  `requeue_inflight` on a crash.
- Approvals and questions are kept indefinitely — both are
  audit trails. `actions::destroy` and answered questions stay
  visible to anything that queries by id.
- Reminder rows are kept after `sent_at` is set (audit trail);
  no automatic vacuum today.
- Scheduled prompts: one-shot rows are deleted on fire by the
  worker; recurring rows live until the operator cancels them
  (`cancel_schedule` MCP / dashboard ✗) which tombstones via
  `cancelled_at_unix`, then `reap_cancelled` drops the row on
  the next worker pass.

### `/harness/hyperhive-events.sqlite` (per agent)

Lives inside each container's bind-mounted `/harness/` dir (host
path: `/var/lib/hyperhive/agents/<name>/harness/hyperhive-events.sqlite`).
One table:

- `events(id, ts, kind, payload_json)` — every `LiveEvent` the
  harness emits during turn loop execution.

The harness writes; the host vacuums. `hive-c0re::events_vacuum`
runs hourly and sweeps every existing agent harness dir. Retention
is **type-scoped**: it deletes only the verbose `stream` rows (the
raw claude `stream-json` deltas — one per text chunk / tool use, the
bulk of the file's size) older than 14 days, and keeps every other
kind (`turn_start`, `turn_end`, `note`, `status_changed`,
`model_changed`, `token_usage_changed`, `turn_state_changed`)
indefinitely — those are small and carry the semantic per-turn
history the operator scrolls back through when debugging a
regression. Age-only within the `stream` kind — no row cap — so a
chatty turn doesn't lose its stream history sooner than a quiet one.
Centralising retention on the host means a misbehaving harness can't
disable its own vacuum and agents don't need any cleanup wiring of
their own.

Path overridable via `HYPERHIVE_EVENTS_DB` (for dev / no-`/harness`
setups). On open failure the `Bus` falls back to no-store mode
rather than crashing the harness — events still broadcast over SSE,
just nothing persisted.

### `/harness/hyperhive-turn-stats.sqlite` (per agent)

Per-turn analytics sink. One row per claude turn captures
identity (`model`, `wake_from`, `result_kind`), timing
(`started_at`, `ended_at`, `duration_ms`), cost (input / output /
cache_read / cache_creation token counts), behaviour
(`tool_call_count` + `tool_call_breakdown_json`), and post-turn
snapshot metrics (`open_threads_count`,
`open_reminders_count` — fetched via the same socket the harness
already uses for `GetOpenThreads` + `CountPendingReminders`).
Bin-loop helpers `build_row` + `record` land each row at
`turn_end`; writes are best-effort, a sqlite hiccup logs + lets
the turn loop continue.

A sibling `bash_commands(ts INTEGER, head TEXT)` table in the same
file is written by the `hive-bash-mcp` daemon (not the harness): one
row per executed bash task recording the normalised command head -
the basename of the first real command, looking past `cd repo &&`
prefixes, env-assignments, and prefix-runners like `sudo`/`env`. It
backs the "favorite tools" view on the /stats page (aggregated
host-side). Best-effort and created on first write
(`CREATE TABLE IF NOT EXISTS`), so it's simply absent until a bash
task runs.

turn-stats.sqlite has **no vacuum** — it's one tiny row per turn
(~hundreds of KB even over months), read directly by the `/stats` page
and the hive-wide stats view, so pruning it would only lose trend
history for no space gain.

### `/state/hyperhive-harness.json` (per agent)

Consolidated harness state file written atomically (`.tmp` + rename) by
`Bus::emit_status` whenever rate-limited or login-failed flags change.
Shape:

```json
{ "rate_limited": false, "needs_login": false }
```

- `rate_limited` — set when the harness detects a 429 from the Claude
  API; cleared by any subsequent status emit. Drives
  `ContainerView.rate_limited` on the dashboard.
- `needs_login` — set when a turn hits 401 (expired OAuth credentials);
  cleared by `"online"` status (re-auth completed). Drives the
  `needs_login` flag alongside the `claude_has_session` check.

hive-c0re reads this file on each `build_all` sweep (~10s) via
`container_view::read_harness_flags`. Falls back to the legacy individual
sentinel files (`hyperhive-rate-limited`, `hyperhive-needs-login`) if the
JSON is absent, so existing containers keep working through the transition
window before their next rebuild.

### `/var/lib/hyperhive/db/build_logs.sqlite` (host)

Full stdout + stderr capture for every `nixos-container` / `nix
build` invocation the lifecycle layer fires. One row per invocation;
the row accumulates lines as the child runs.

Replaces the legacy 32-line stderr ring buffer that `lifecycle::run`
kept. The ring tail routinely truncated real eval errors ("tried
alternatives" blocks alone are often 30+ lines), so failures bailed
with an arbitrary tail whose full stream only lived in the host
journal. With this table the dashboard can surface the entire log.

Two indices:
- `(agent, started_at)` — backs the per-agent latest-N lookup used
  by the agent card chip.
- `(status, finished_at)` — backs the retention sweep that runs
  as part of the existing hourly vacuum.

Writes are best-effort: `append_stdout` / `append_stderr` / `finish`
log a warning on sqlite error and let the build continue. A failed
log row never blocks a rebuild.

### `/harness/hyperhive-model` (per agent)

Single-line text file holding the claude model name currently
selected for this agent (default `haiku` when absent). Written by
`Bus::set_model` whenever the operator flips it via `/model
<name>` in the web terminal. Read once at harness boot in
`Bus::new`. Path overridable via `HYPERHIVE_MODEL_FILE`.
Survives destroy/recreate, gone on `--purge`.

## State dirs (per agent)

Under `/var/lib/hyperhive/agents/<name>/`:

- `config/` — the proposed nix repo (root-agent-editable). Bind-mounted
  **read-only** to `/agents/<name>/config` inside the sub-agent's own
  container so the agent can inspect what defines it and request
  precise changes from the root agent; RW into the root agent via the
  `/agents` tree bind.
- `claude/` — claude OAuth credentials, bind-mounted RW to
  `/home/<name>/.claude` inside the container.
- `state/` — durable notes and `hyperhive-harness.json`. Bind-mounted
  to `/agents/<name>/state` inside the container (uniform for
  all agents). The `$HYPERHIVE_STATE_DIR` env var exposes
  the same path to in-container scripts. Notable files written here
  by the harness:
  - `hyperhive-status` — single-line free-text status string written
    by `set_status`; cleared on explicit `set_status("")`. Read by
    hive-c0re and the per-agent `/api/dashboard-state` endpoint to
    surface the status chip on the dashboard. Absent when no status
    is set.
  - `hyperhive-harness.json` — rate-limited / needs-login flags read
    by the dashboard's async container-state fetch. See
    `docs/web-ui/dashboard.md::Container row`.
- `harness/` — harness-internal ephemeral state; not intended for
  agent consumption. Bind-mounted to `/agents/<name>/harness`
  inside the container (`$HYPERHIVE_HARNESS_DIR`). Contents:
  - `bash-tasks/` — task JSON + stdout/stderr files for
    background `mcp__bash__run` jobs. JSON files are
    `<id>.json` (status + tails), `<id>.out` / `<id>.err`
    (full captured output). `hive-c0re::bash_tasks_vacuum` runs
    hourly and deletes terminal task trios older than 48 hours;
    non-terminal (still-running) tasks are never deleted by vacuum.
  - `mcp-loose-ends/` — JSON files published by external MCP daemons
    (e.g. `hive-bash-mcp`, `hive-matrix-mcp`) listing their active
    loose-end summary strings. Each file is `<daemon>.json` containing
    a JSON array of plain-text lines. Read by `get_loose_ends` to
    surface active background work without hardcoding per-MCP
    knowledge in the harness. Files are created/removed by the
    external daemons themselves.
  - `hyperhive-events.sqlite` — turn-loop event log.
  - `hyperhive-turn-stats.sqlite` — per-turn timing stats.
  - `hyperhive-model` — single-line model name override file.

### Parent access to child state

A parent agent gets each direct child's `state`, `harness`, and
`config` dirs bind-mounted **read-write** (`bind_child_agent_dirs` in
`lifecycle.rs`). The RW on `state` is deliberate, not an oversight: a
parent manages its children, which includes writing into a child's
state for recovery (e.g. seeding notes, clearing a stuck sentinel) as
well as reading it. `config` is RW because the parent authors proposed
config changes for the child (the approval flow commits into the
child's config repo), and `harness` is RW for the same management
reasons. Per-child isolation still holds: a container only ever has
its *own* dirs plus its direct children's bind-mounted, never a
sibling's.

Under `/var/lib/hyperhive/applied/<name>/` — the hive-c0re-only
applied repo. Tracks `flake.nix` (module-only boilerplate; never
edited after first spawn) + `agent.nix` (the actual config; the
root agent's edits land here via the approval flow) + any other
files committed via the approval flow. `.git/` carries the proposal /
approved / building / deployed / failed / denied tag history.

Under `/var/lib/hyperhive/meta/` — the swarm-wide deploy flake plus
system-level config files. Single git repo for the whole host; every
hive-c0re mutation that should survive a restart is committed here.
Contents:

- `flake.nix` — declares one `nixpkgs` input per agent + one
  `nixosConfigurations.<n>` output per agent. `flake.lock` is the
  canonical "what's deployed where." The git log is the deploy
  audit trail (one commit per successful deploy or hyperhive bump).
- `topology.json` — parent/child agent graph
  (`{ "alice": "root", "bob": "alice", "root": null }`).
  Written by `topology::set_parent`; read by the dashboard, the
  renderer, and `<parent>` / `<children>` recipient resolution.
- `tool-groups.json` — per-agent MCP tool group grants
  (`{ "alice": ["messaging", "inbox", "execution"] }`). Written by
  `tool_groups::set_groups`; injected as `HIVE_TOOL_GROUPS` env
  var into each agent's container.
- `capabilities.json` — per-agent capability grants
  (`{ "atlas": ["read_host_journal"] }`). Written by
  `capabilities::set_caps`; injected as `HIVE_CAPABILITIES` env
  var. Absent agents have no extra capabilities.

The root agent has the meta dir RO-mounted at `/meta/`.

Marker file `/var/lib/hyperhive/.meta-migration-done` is
written by the startup migration after every container has
been repointed at `meta#<n>`. Removing it forces a re-run on
next hive-c0re start (idempotent — only the actual repoint
step would re-fire).

## Destroy vs purge

- `DESTR0Y` (default) — stops + removes the nspawn container,
  drops the systemd drop-in, fails any pending approvals. State
  dirs stay put; the agent appears in the dashboard's K3PT ST4T3
  section as a tombstone with `⊕ R3V1V3` and `PURG3` actions.
  `R3V1V3` queues a Spawn approval that reuses the kept state on
  approve (no re-login).
- `PURG3` (opt-in via the dashboard button or
  `hive-c0re destroy --purge <name>`) — DESTR0Y plus wipes
  `/var/lib/hyperhive/{agents,applied}/<name>/`. Config history,
  claude creds, /state/ notes, and the harness dir are all gone.
  No undo.

The root/bootstrap container is **imperative** infrastructure — managed
end-to-end by hive-c0re, not declared in the host's NixOS config.
`auto_update::ensure_root_agent` recreates it on the next hive-c0re
startup if it's absent (bypassing the approval queue, as required
infrastructure). A soft policy guard in `actions::destroy` currently
refuses to destroy it; even without that guard, destroying it would only
be transient — hive-c0re brings it back on the next startup.

### btrfs subvolumes for `/var/lib/hyperhive/agents/<name>`

On a btrfs host, a brand-new agent's state root is created as a
**btrfs subvolume** instead of a plain directory (progressive
enhancement — see the #1762 lane). This is a no-op fallback on
non-btrfs hosts and for any agent whose root already exists, so
nothing is auto-migrated: existing agents keep their plain dirs
until an explicit opt-in upgrade.

- **Creation:** `lifecycle::ensure_agent_state_subvolume` runs before
  the per-agent subdirs are created (spawn / rebuild / InitConfig).
  It skips the work when the root already exists; otherwise it asks
  hive-priv (`EnsureAgentSubvolume`) to `btrfs subvolume create` the
  root when the FS is btrfs (`statfs` magic gate) and chown it to the
  `hive-core` user so the normal `state/` `claude/` `harness/` mkdirs
  succeed inside it.
- **DESTR0Y keeps the subvolume** exactly like a plain dir — revival
  reuses it untouched.
- **PURG3 deletes it correctly:** a subvolume root can't be removed
  with `rmdir`/`remove_dir_all`, so purge first calls hive-priv
  (`DeleteAgentSubvolume`) which `btrfs subvolume delete`s it iff it's
  actually a subvolume, then the normal `remove_dir_all` sweep covers
  plain-dir agents + the applied dir.

Per-subvolume disk-usage accounting and optional quotas are a
follow-up (the qgroup work), not part of the base migration.

## Run-time dirs

`/run/hyperhive/` is tmpfs-backed (systemd `RuntimeDirectory=`) but
preserved across hive-c0re restarts via `RuntimeDirectoryPreserve=yes`.
Without that, every restart wipes bind sources and existing
containers can't be started.

- `/run/hyperhive/host.sock` — admin socket (host-side CLI).
- `/run/hyperhive/agents/<name>/mcp.sock` — per-agent socket
  (bind-mounted into the container as `/run/hive/mcp.sock`).

On startup, `Coordinator::register_agent` drops any prior socket
task before rebinding — idempotent so a hive-c0re restart followed
by `rebuild alice` recreates the agent's socket without a clean
reinstall.

## First-boot agent-user migration

The harness runs as a per-agent unix user inside the container
(`hyperhive.user.name`, defaults to the agent's logical label so each
container has a uniquely-named user). Operators with legacy root-owned
state dirs need a one-time data shuffle so they don't lose their claude
session.

`system.activationScripts.hive-agent-user-migrate` (in
`nix/templates/harness-base.nix`) runs on every activation,
marker-guarded so the substantive moves only happen once per
container lifetime:

1. **`${homeDir}` exists with the right ownership** — covers the
   very first boot before `useradd`'s `createHome` has had a
   chance to chown. Also re-applies on every rebuild in case the
   meta-flake's per-agent name evolves (rare).
2. **Migrate any leftover `/root/.claude` content into
   `${homeDir}/.claude`** — legacy `claude` wrote to root's
   empty home; the bind mount didn't exist yet. Marker
   (`/var/lib/hive-agent-user-migrated`) guards single-shot.
   `cp -an` (no-clobber) so any pre-existing files at the new
   location win — never blow over data already there.
3. **Chown the bind-mounted state dir** (`/agents/*/state`)
   recursively so the agent user can read/write it. Wildcard
   matches the single agent that container sees; `-h` skips
   symlinks the agent might have planted.
4. **Chown the `~/.claude/` bind-mount** recursively. Legacy
   `claude` wrote `.credentials.json` 0600 root:root; the
   current harness reads `~/.claude/` as the agent user to decide
   Online vs NeedsLogin in `login::has_session`. Without the
   chown the existing credentials get silently treated as "no
   session" and the operator re-prompts every boot.

The activation script will eventually become unnecessary once no
operators have legacy root-owned state dirs left to migrate; drop
the body + marker check at that point.

## Matrix per-agent daemon + token-arrival trigger

`hive-matrix-daemon` is a long-running matrix-sdk Client + sync
process per agent. Holds the unix socket the stdio
`hive-matrix-mcp` bridge talks to, emits hyperhive wake signals
on incoming room events via `/run/hive/mcp.sock`. Conditional on
`hyperhive.matrix.enable` (which both the daemon AND the
auto-injected `extraMcpServers.matrix` entry read).

Socket path lives inside the systemd-managed runtime dir
(`RuntimeDirectory = "hive-matrix"` → `/run/hive-matrix/`, owned by
the agent user) so the daemon can bind without needing root over
`/run/` itself. Both daemon + bridge agree on the path via the
`HIVE_MATRIX_SOCKET` env var.

**First-boot ordering**: hive-c0re provisions the matrix token AFTER
agent containers come up. Without the path-trigger sibling
(`systemd.paths.hive-matrix-daemon`, `PathExistsGlob =
/agents/*/state/matrix-token`), the daemon would exit 0 quietly the
first time it ran and the MCP would have no backend until the next
restart. The `.path` unit makes the appearance of the token re-fire
the service so the daemon comes alive in the same boot cycle as
provisioning. `matrix-avatar-sync.path` uses the same pattern for
the icon-upload oneshot.

### matrix-avatar-sync (two-step media + profile dance)

Mirrors the forge-avatar oneshot's shape (`docs/conventions.md::
Best-effort oneshot services`) but differs in protocol: matrix
avatars are a two-step `POST /media/r0/upload` → `PUT
/profile/<user_id>/avatar_url` dance, both authenticated by the
`access_token` written by `hive-c0re::matrix::ensure_user_for` to
`<state>/matrix-token`.

Triggered by EITHER boot (`wantedBy = multi-user.target`) OR the
sibling `matrix-avatar-sync.path` firing on token appearance. Both
paths re-run the oneshot idempotently — running the avatar set
twice is harmless.

Critically: **`RemainAfterExit = false`** (not the more common
`true` for oneshots). systemd treats `RemainAfterExit = true`
oneshots as "still running" after the first exit, so the second
trigger from the `.path` watcher becomes a no-op. Setting it to
`false` lets re-fires actually re-execute. The trade-off is the
service unit shows `inactive (dead)` between fires — visible in
`journalctl` but harmless; the `.path` unit drives the lifecycle.