---
status: draft
last_updated: 2026-10-05
---

# Reference read: honker queue / scheduler / outbox / lock maintenance machinery

Per-agents conventions: reference checkouts are read freely, never
wired in; checkout state noted when findings depend on code specifics.

**Checkout:** `/workspace/honker` @ `f4e53c6`
(`node-v0.5.1-10-gf4e53c6`), matching the AGENTS.md reference revision.
**Versions:** `honker-core` **0.5.0** (`honker-core/Cargo.toml`), `honker`
Rust wrapper **0.5.0** (`packages/honker-rs/Cargo.toml`). The Rust
binding is *excluded* from the root workspace; all real machinery is in
`honker-core/src/{lib.rs, honker_ops.rs, cron.rs}`.

**Architecture in one sentence:** SQLite tables (`_honker_live`,
`_honker_dead`, `_honker_locks`, `_honker_scheduler_tasks`,
`_honker_results`, `_honker_notifications`, rate-limit/stream tables) +
SQL scalar functions (`honker_*`) implemented once in Rust
(`honker_ops::attach_honker_functions`), consumed identically by
Python/Node/Rust bindings; cross-process wake is `PRAGMA data_version`
polling (1 ms default) driving an in-process channel — not
LISTEN/NOTIFY.

## 1. Queues

### 1.1 Job table schema

`BOOTSTRAP_HONKER_SQL` — `honker-core/src/lib.rs:352-432`:

**`_honker_live`** (lib.rs:353-367) — pending and processing both live
here:

| column | type | notes |
|---|---|---|
| `id` | INTEGER PK AUTOINCREMENT | |
| `queue` | TEXT NOT NULL | namespace within one table |
| `payload` | TEXT NOT NULL | stored as JSON string |
| `state` | TEXT DEFAULT `'pending'` | two states: `'pending'`, `'processing'` |
| `priority` | INTEGER DEFAULT 0 | higher = earlier (`ORDER BY priority DESC`) |
| `run_at` | INTEGER DEFAULT `(unixepoch())` | readiness deadline |
| `worker_id` | TEXT | current claim holder |
| `claim_expires_at` | INTEGER | visibility deadline; moves on heartbeat |
| `attempts` | INTEGER DEFAULT 0 | bumped on **every** claim, including reclaims |
| `max_attempts` | INTEGER DEFAULT 3 | per-row, frozen at enqueue |
| `created_at` | INTEGER DEFAULT `(unixepoch())` | |
| `expires_at` | INTEGER | job-level expiry; NULL = never |
| `claimed_at` | INTEGER, nullable | start of *current* attempt; migration added (lib.rs:486-508) |

Partial indexes tuned to the hot paths (lib.rs:368-376): claim index
`(queue, priority DESC, run_at, id) WHERE state IN
('pending','processing')`; pending index `(queue, run_at)`; processing
index `(queue, claim_expires_at)`. Dead rows never touch the claim
index.

**`_honker_dead`** (lib.rs:377-388): `id`, `queue`, `payload`,
`priority`, `run_at`, `attempts`, `max_attempts`, `last_error`,
`created_at`, `died_at`. **Move, not flag**: dead-lettering physically
DELETEs from `_honker_live` and INSERTs into `_honker_dead`. No
retention/expiry on dead rows — "Never scanned by the claim path;
retention policy is the user's problem" (lib.rs:345-347). No
`DELETE FROM _honker_dead` anywhere in the repo.

### 1.2 Enqueue and its options

Core signature (`honker_ops.rs:984-993`):

```rust
pub fn enqueue(
    conn: &Connection, queue: &str, payload: &str,
    run_at: Option<i64>, delay: Option<i64>,
    priority: i64, max_attempts: i64, expires: Option<i64>,
) -> rusqlite::Result<i64>
```

SQL function `honker_enqueue(...)` (honker_ops.rs:593-619). Rust-level
`EnqueueOpts` (`packages/honker-rs/src/lib.rs:438-444`) — note
`max_attempts` is *not* here; it comes from queue-level `QueueOpts`
(`visibility_timeout_s: 300, max_attempts: 3`, lib.rs:421-434):

```rust
pub struct EnqueueOpts {
    pub delay: Option<i64>,
    pub run_at: Option<i64>,
    pub priority: i64,
    pub expires: Option<i64>,
}
```

Semantics (honker_ops.rs:976-1000):

- **run_at vs delay precedence**: `delay` wins — `run_at = unixepoch()
  + delay` if delay set; else literal `run_at`; else `now`.
- **expires**: relative seconds → `expires_at = unixepoch() + expires`;
  NULL = never expires.
- **No synthetic wake row on enqueue** — the INSERT advancing
  `data_version` *is* the wake; an earlier design writing a
  `_honker_notifications` row per enqueue grew unboundedly
  (honker_ops.rs:1002-1006).

`arg_i64`/`arg_opt_i64` (honker_ops.rs:40-54) accept REAL-typed whole
numbers because better-sqlite3 binds every JS number as REAL — interop
lesson (fractional values error with a diagnostic).

### 1.3 Claim mechanics

```rust
pub fn claim_batch(conn: &Connection, queue: &str, worker_id: &str,
                   n: i64, timeout_s: i64) -> rusqlite::Result<String>
```
(honker_ops.rs:848-914). `timeout_s` **is** the visibility timeout,
set per-claim (the Rust binding passes static `QueueOpts
.visibility_timeout_s`, honker-rs lib.rs:584-591).

Single atomic `UPDATE ... WHERE id IN (SELECT ...) RETURNING`
(honker_ops.rs:866-886):

- Claim predicate: `state IN ('pending','processing') AND attempts <
  max_attempts AND (expires_at IS NULL OR expires_at > unixepoch()) AND
  ((state='pending' AND run_at <= now) OR (state='processing' AND
  claim_expires_at < now))`.
- Claim action: `state='processing'`, `worker_id=worker`,
  `claim_expires_at = now + timeout_s`, `claimed_at = now`,
  `attempts += 1`.
- Ordering: `priority DESC, run_at ASC, id ASC`, `LIMIT n`.

**Reclaim = another attempt.** Claiming bumps `attempts` on reclaims
too — visibility timeouts consume the retry budget. `claimed_at` is
refreshed on reclaim but **not** on heartbeat (doc honker_ops.rs:831-847;
test honker_ops.rs:3103-3149).

`claim_one` is a thin `claim_batch(worker_id, 1)` (honker-rs
lib.rs:606-609).

**Pre-claim dead-letter sweep**: every `claim_batch` first runs
`dead_letter_exhausted_claimable` (honker_ops.rs:781-829) — rows at
`attempts >= max_attempts` that are claimable-reclaimable move to
`_honker_dead` with `last_error='max attempts exceeded'` before the
claim UPDATE (covers "worker died right after the last allowed claim").

**Idle-wake helper**: `honker_queue_next_claim_at(queue) -> unix_ts`
(honker_ops.rs:936-970) — earliest future `run_at` (pending) or
`claim_expires_at + 1` (processing with budget); 0 if nothing. Used by
the Rust `ClaimWaker::next` loop (honker-rs lib.rs:805-845): wake on
data_version or sleep until `next_at`, no busy-poll.

### 1.4 Visibility timeout / heartbeat / renewal

```rust
pub fn heartbeat(conn, job_id, worker_id, extend_s) -> Result<i64>
```
(honker_ops.rs:1306-1323); 1 = extended, 0 = refused.

- Heartbeat is a **renewal** (visibility extension), *not* a progress
  signal — no progress field exists. Sets `claim_expires_at =
  unixepoch() + extend_s` (absolute reset from now, not additive).
- Guard: `WHERE id = ? AND worker_id = ? AND state = 'processing' AND
  claim_expires_at >= unixepoch()` — a **late heartbeat after the
  visibility timeout is refused** so it cannot steal the job back from
  a reclaimer (dual-execution guard, honker_ops.rs:1312-1314).
- **Missed heartbeat** ⇒ `claim_expires_at` passes ⇒ row claimable by
  the normal predicate; a reclaiming claimer consumes an attempt.
  Nothing transitions the row on lapse; stale `worker_id` etc. remain
  until a next claim overwrites them (honker_ops.rs:843-847).
- No per-binding heartbeat thread in core; cadence is caller-
  implemented.

### 1.5 Retry behavior — attempts and backoff

```rust
pub fn retry(conn, job_id, worker_id, delay_s, error) -> Result<i64>
```
(honker_ops.rs:1045-1123). Requires a still-valid processing claim;
`attempts >= max_attempts` ⇒ dead-letter (savepoint-wrapped
DELETE→INSERT, honker_ops.rs:1080-1107); else `pending` with
`run_at = unixepoch() + delay_s`, claim fields cleared.

**Backoff is NOT in the queue core.** `retry` takes a caller-chosen
`delay_s`. Curves live in wrappers:

- Rust `Outbox::retry_delay`: `base_backoff_s * 2^(attempts-1)`,
  saturating (honker-rs lib.rs:543-549).
- Python `_compute_delay`: `retry_delay * backoff**(attempts-1)`
  (`packages/honker/python/honker/_worker.py:108-114`); `@task` defaults
  `retry_delay_s=60`, `backoff=1.0` (constant).
- **No jitter and no cap in either** (Rust caps only via `saturating_mul`).

### 1.6 Dead-letter handling

- Dedicated `_honker_dead`; **move semantics** (§1.1). Triggers:
  (a) `retry()` at budget (honker_ops.rs:1080-1107), (b) explicit
  `fail()` (honker_ops.rs:1135-1192), (c)
  `dead_letter_exhausted_claimable` pre-claim (honker_ops.rs:781-829),
  (d) `sweep_expired` expiration (honker_ops.rs:1336-1381).
- `last_error` strings: caller error, `'max attempts exceeded'`,
  `'expired'`.
- **Retention: none.** No sweep/TTL/pruning of dead rows exists.
- All four move-sites are wrapped in a shared savepoint helper
  `in_savepoint` (honker_ops.rs:118-254) — `DELETE ... RETURNING` +
  decode + INSERT had a half-failing window; a failing decode/INSERT
  previously produced `live=0, dead=0` **silent job loss** (CHANGELOG
  "Core SQLite error propagation"; `UnwindUndo` undoes the frame if the
  body panics). The savepoint hardening is very recent, post-0.5.1 work
  in the CHANGELOG "Unreleased" section. Most instructive correctness
  pattern in the codebase.

### 1.7 `sweep_expired`

```rust
pub fn sweep_expired(conn, queue) -> Result<i64>
```
(honker_ops.rs:1336-1381). **Only sweeps `state='pending'` rows with
`expires_at IS NOT NULL AND expires_at <= now`** → `_honker_dead` with
`last_error='expired'`. Does **not** touch processing rows — expired
claims are handled lazily by the claim predicate. Python doc: "The
claim path already ignores expired rows, so sweep is cleanup-only — not
correctness-critical" (`_honker.py:387-394`).

### 1.8 cancel / get_job / ack_batch

```rust
pub fn cancel(conn, job_id) -> Result<i64>          // honker_ops.rs:1203-1209
pub fn get_job(conn, job_id) -> Result<String>      // :1220-1295
pub fn ack(conn, job_id, worker_id) -> Result<i64>  // :1028-1035
pub fn ack_batch(conn, ids_json, worker_id) -> Result<i64> // :920-934
```

- **cancel**: unconditional `DELETE ... WHERE id=? AND state IN
  ('pending','processing')` regardless of which worker holds it. Not
  an interrupt — the holder's next `ack`/`heartbeat` returns 0
  (honker-rs docs lib.rs:625-631).
- **get_job**: reads `_honker_live` only → **dead jobs are invisible**;
  JSON on hit, **empty string on miss** (honker-rs maps to `None`,
  lib.rs:642-650). `claimed_at: null` for never-claimed jobs.
- **ack/ack_batch**: `DELETE ... WHERE id IN (...) AND worker_id=? AND
  claim_expires_at >= now RETURNING id`, returning count. Deliberately
  savepoint-free (honker_ops.rs:916-919). Ack fails (0) if the claim
  expired. Note: ack doesn't check `state='processing'` — keys off
  `worker_id` + `claim_expires_at` only (harmless today, implicit).

## 2. Scheduler

### 2.1 Storage schema

`_honker_scheduler_tasks` (lib.rs:400-410): `name` PK, `queue`,
`cron_expr`, `payload`, `priority` (default 0), `expires_s` (nullable),
`next_fire_at` NOT NULL, `enabled` INTEGER DEFAULT 1, `max_attempts`
INTEGER DEFAULT 3. Runtime ALTER migrations tolerate the
concurrent-bootstrap "duplicate column" race (lib.rs:443-508). No
`last_fired_at`, no `tz` column — cron arithmetic is **system local
time**.

### 2.2 Surface

Core (honker_ops.rs): `scheduler_register` (:1490-1536),
`scheduler_unregister` (:1538-1551), `scheduler_tick` (:1583-1654),
`scheduler_soonest` (:1656-1664), `scheduler_pause`/`resume`
(:1669-1689, toggling `enabled`), `scheduler_list` (:1694-1752),
`scheduler_update` (:1759-1844). Plus `honker_cron_next_after(expr,
from_unix)` DETERMINISTIC SQL function (:683-692).

Rust binding (`packages/honker-rs/src/lib.rs:1365-1584`): `add`,
`add_with_max_attempts`, `remove`, `tick`, `soonest`, `pause`,
`resume`, `list`, `update` (with `ScheduleUpdate { cron_expr, payload,
priority, expires_s: Option<Option<i64>> }` — inner Option
distinguishes "clear" from "leave alone"), `update_max_attempts`, and
the blocking `run(stop, owner)` leader loop. Python mirrors
(`_scheduler.py:113-437`).

Register semantics: upsert by name, replaces entirely; `next_fire_at`
= next cron boundary **strictly after now**; clamps `max_attempts < 1`
to 1.

### 2.3 Tick and catch-up

`schema_tick(conn, now_unix) -> JSON [{name, queue, fire_at, job_id}]`
(honker_ops.rs:1583-1654):

- Selects `WHERE next_fire_at <= now AND enabled = 1`.
- Per task, loops while `next_fire_at <= now`: enqueue (run_at NULL =
  claim immediately, task-level `expires_s`/`max_attempts` applied),
  then `next_fire_at = cron_next_after(expr, next_fire_at)` — one fire
  per missed boundary, minute-by-minute catch-up.
- `SCHEDULER_MAX_CATCHUP_FIRES = 64` cap per task per tick
  (honker_ops.rs:1564-1575); beyond the cap remaining boundaries
  **skip** — `next_fire_at` jumps to `next_after(now)`. Documented as
  semantic: "Run the scheduler continuously, use coarser schedules, or
  raise this constant."
- Final `next_fire_at` persisted in a separate UPDATE (honker_ops.rs
  :1647-1651) within the caller's transaction — enqueue+advance commit
  together.
- Dedup: no DB-level claim token; the advance-then-return contract
  under `BEGIN IMMEDIATE` means at most one ticker observes an unfired
  boundary — pinned by a 10-thread race test
  (`tests/test_scheduler.py:397-470`). The leader lock is the
  production gate; the SQL is "still safe if someone forgets it".

**Guarantee: at-least-once per boundary, up to 64-boundary backlog;
beyond that, gap-skip by design.** Crash mid-tick rolls back both
enqueues and the advance (boundary refires).

### 2.4 Leader loop / election

Election is a **named TTL lock in `_honker_locks`**, not SQLite
advisory APIs:

- Rust `Scheduler::run` (lib.rs:1509-1584): `LOCK_NAME="honker-scheduler"`,
  TTL 60s, heartbeat every 20s (Python `_scheduler.py:135-137`, TTL 60,
  heartbeat 30). Non-leaders poll every 5s.
- Leader loop (lib.rs:1539-1584): renew lock → on failure **exit
  before ticking** (no dual-fire alongside the thief) → `tick()` →
  `soonest` → sleep `min(heartbeat_interval, until_soonest)`.
- Python `_main_loop` additionally re-proves ownership *before every
  fire* (`_scheduler.py:382-437`), runs tick+soonest in one writer tx.
  Losing the lock raises `LeadershipLost`.
- Wake-on-register: register/unregister/pause/resume/update rely on
  `data_version` advancing (a former synthetic notification row was
  removed as unbounded-growth — `scheduler_wake` is now a no-op,
  honker_ops.rs:1553-1562).

### 2.5 Cron parsing (`cron.rs`, 473 lines)

- 5-field cron (`min hour dom month dow`), 6-field with seconds, and
  `@every <n><unit>` (s/m/h/d) (cron.rs:1-14, 97-129). Full syntax:
  `*`, ranges, lists, steps; dow 0=Sunday; field validation with good
  errors (cron.rs:131-178).
- Next-boundary search: iterative scan, bounded to 100 years
  (cron.rs:207-315). DST handled: spring-forward gap skips to real
  time, ambiguous fall-back picks the first instantiation
  (cron.rs:330-358; tests cron.rs:456-472).
- **Brittleness — system local timezone dependence**: no TZ parameter
  in the public surface (`next_after_unix` uses `chrono::Local`,
  cron.rs:319-321; tz-parameterized variant is `pub(crate)` test-only).
  A server TZ change silently re-times every cron task; stored
  schedules are not TZ-qualified.

## 3. Outbox

Pattern: **an outbox is a regular queue named `_outbox:{name}`** — no
separate table, no separate delivery semantics (honker-rs
lib.rs:478-492; `_honker.py:865-934`).

Rust shape (`OutboxOpts`: `visibility_timeout_s: 60, max_attempts: 5,
base_backoff_s: 5`, lib.rs:454-469):

```rust
pub fn run_once<F, E>(&self, worker_id: &str, delivery: F) -> Result<bool>
where F: FnMut(serde_json::Value) -> Result<(), E>
```
(lib.rs:516-541): `claim_one` → parse payload → `delivery(payload)` →
Ok ⇒ `job.ack()` (ack failure surfaced as error, :527-529) ⇒ Err ⇒
`job.retry(base_backoff_s * 2^(attempts-1), err)` (:531-538). A **pull**
worker — app calls `run_once` in its own loop.

Transactional enqueue: `outbox.enqueue_tx(&tx, ...)` routes through
the *caller's* `Transaction` (lib.rs:506-513); single
mutex-guarded-connection means same-thread in-tx ops must use `_tx`
variants (lib.rs:241-250). Failure path: at-least-once with
exponential backoff, dead-lettering via normal budget mechanics.
**No heartbeat inside `run_once`** — delivery slower than
`visibility_timeout_s` (default 60s) can have its claim expire
mid-delivery and be redelivered (honker's own outbox is exposed to the
dual-execution window).

## 4. Locks (maintenance-relevant)

`_honker_locks (name TEXT PK, owner TEXT NOT NULL, expires_at INTEGER
NOT NULL)` (lib.rs:389-393).

```rust
pub fn lock_acquire(conn, name, owner, ttl_s) -> Result<i64>   // 1/0  honker_ops.rs:1387-1415
pub fn lock_release(conn, name, owner) -> Result<i64>          // :1417-1423
pub fn lock_renew(conn, name, owner, ttl_s) -> Result<i64>     // 1/0  :1431-1442
```

- `lock_acquire`: opportunistic per-name expiry sweep
  (`DELETE WHERE name=? AND expires_at <= now`) + `INSERT OR IGNORE` +
  read-back. The PK on `name` prevents dual acquisition.
- **`INSERT OR IGNORE` does not refresh TTL on same-owner re-acquire**
  — hence `lock_renew` as a separate function (honker_ops.rs:1425-1431;
  lib.rs SQL comment :329-332); acquire returns 1 while silently
  keeping the old expiry. `lock_renew` requires `(name, owner)` match
  and positive ttl.
- `Lock::heartbeat(ttl_s)` RAII wrapper (honker-rs lib.rs:1682-1691),
  with the honest caveat "holding the `Lock` value alone does not
  guarantee you still own the lock".
- **No general lock-expiry sweep** — expired locks for names nobody
  acquires again persist ("Expired rows ... are opportunistically
  pruned on every acquire attempt", `_honker.py:962-965`). Locks also
  serve as operator mutexes (skip-overlapping-runs recipe,
  `_honker.py:1160-1170`).

## 5. Notifications pruning

`_honker_notifications (id, channel, payload, created_at)`
(lib.rs:308-315). **Never auto-pruned** — "no magic timer" (lib.rs
:303-305; tests pin that `notify()` never prunes, `_honker.py`
:1182-1208).

- Rust `prune_notifications(older_than_s)` (lib.rs:323-332) and
  `prune_notifications_keep_latest(max_keep)` (lib.rs:336-351 —
  rank-based; OFFSET trick correct across id gaps; `max_keep < 0`
  errors).
- Python combines both conditions with **OR semantics** — aggressive
  `older_than_s` is not blocked by `max_keep`; max_keep "is not a
  floor" (`_honker.py:1182-1245`).

## 6. Result storage (brief)

`_honker_results (job_id INTEGER PK, value TEXT, created_at,
expires_at)` (lib.rs:411-416).

`result_save` (ttl ≤ 0 ⇒ NULL), `result_get` (expired reads as None),
`result_sweep` (honker_ops.rs:1850-1900). Python adds
`get_result -> (found, value)` and `wait_result` (`_honker.py:431-498`);
the Python worker saves results **before** ack and swallows
result-persistence failures so side effects aren't duplicated
(`_worker.py:75-83`).

## 7. Maintenance defaults: what runs automatically?

**Nothing. Everything is consumer-driven.** No background sweeper
thread in honker-core (only the `UpdateWatcher` data-version poller,
lib.rs:942-1026). `sweep_expired`, `result_sweep`, `rate_limit_sweep`,
`prune_notifications*`, `scheduler_tick`, `lock_renew` all invoked by
user code; the scheduler tick only **enqueues**. Implicit maintenance:
(a) pre-claim dead-lettering inside `claim_batch` (honker_ops.rs
:855-859), (b) opportunistic expired-lock deletion inside
`lock_acquire` (honker_ops.rs:1393-1397). Python workers get
idle-poll fallback (default 5s) alongside data_version wake
(`_honker.py:374-385`).

## 8. Observed defects / brittleness (feeds OQ-06)

1. **Doc drift** in the Rust binding's `sweep_expired`: "Sweep expired
   processing rows back to pending" (lib.rs:652) — actual semantics is
   pending → `_honker_dead` (`last_error='expired'`), never
   processing→pending (honker_ops.rs:1336-1381).
2. **Zombie processing rows**: a `processing` row whose job-level
   `expires_at` passed is unreachable by every path if its worker died
   — claim predicate requires future expiry (honker_ops.rs:878),
   pre-claim dead-lettering likewise (honker_ops.rs:792),
   `sweep_expired` is pending-only (:1346). Sits in `_honker_live`
   forever unless `cancel`ed or a still-live worker retries it. Narrow
   but real.
3. **Silent-boundary skip after a scheduler outage** — cap 64 then
   jump (honker_ops.rs:1612-1621). Deliberate and documented, but part
   of the guarantee.
4. **Local-timezone cron** — `chrono::Local` hard-wired in the public
   surface (cron.rs:319-321).
5. **No dead-row retention anywhere** — `_honker_dead`,
   `_honker_notifications`, `_honker_stream` grow unbounded unless the
   user schedules pruning (lib.rs:345-347, `_honker.py:88-90`).
6. **`lock_acquire` doesn't refresh TTL for same-owner re-acquire**
   (honker_ops.rs:1398-1401); `_honker_locks` has no standalone sweep.
7. **Backoff has no jitter/cap** (Python plain `2**(attempts-1)`,
   `_honker.py:930`; Python no overflow guard, Rust saturates).
8. **Reclaim consumes the attempt budget** (honker_ops.rs:870-872) —
   coherent with dead-lettering but a footgun ("timeout ≠ attempt"
   assumptions are wrong).
9. **Heartbeat refusal after expiry** leaves an at-least-once
   dual-execution window by design (honker_ops.rs:1312-1321) —
   downstream idempotency is the user's job; docs admit it
   (`_scheduler.py:122-133`).
10. **`get_job` cannot see dead jobs** (honker_ops.rs:1237-1240) —
    post-mortem diagnosis is SQL-only.
11. **Savepoint-class defects** (issue #133, post-0.5.1 hardening):
    any `DELETE ... RETURNING` + decode + INSERT can strand rows in
    neither table on a mid-flight error; fixed recently with
    `in_savepoint` (honker_ops.rs:90-117, tests :2340-2700).
12. **`ack`/`ack_batch` don't check `state='processing'`**
    (honker_ops.rs:922-926) — implicit rather than enforced.

## 9. Patterns worth carrying over

- One shared SQL-scalar implementation for all bindings, tested once.
- Partial indexes matching the claim hot path; dead rows out of it.
- `unixepoch()` second-precision timestamps (single clock source);
  simple, multiprocess-safe.
- Wake = `PRAGMA data_version` delta, coalesced; no wake rows in the
  DB (the "no synthetic notification" fix appears three times:
  honker_ops.rs:1002, 1119-1120, 1553-1562).
- `queue_next_claim_at` as the sleep-computing claim counterpart
  (zero-poll idle workers).
- Savepoint-safe multi-statement mutations.

## 10. Aftermath — where these findings landed

OQ-06 consumed this document and went further: a follow-on quality
read ([quality-read-honker-core.md](quality-read-honker-core.md))
cross-checked the *published* crates.io artifact against this checkout
and found the savepoint/error-propagation fix train (§8 items 11, the
CHANGELOG "Unreleased" work) unpublished — firing ADR-005's fork
trigger ([ADR-011](../architecture/decisions/011-sqlite-substrate-fork.md)).
The defect list in §8 is now the fork's fix/inheritance register; this
document remains the accurate read of the reference revision.