---
status: draft
last_updated: 2026-10-10 (ADR-024 — the mem engine adopted as wave 6,
release readiness renumbered to wave 7; wave 6 decomposed — eleven
tasks per the pg-wave rhythm with the tx overlay load-bearing. Waves
1–5 implemented and reviewed; engine specs stable. Wave-5 review
residue decomposed — pg-fix-scheduler-fire-wake; flake-watch carried
to wave 7.)
---

# alkstore — Implementation plan

Wave-based decomposition of the architecture
(`docs/architecture/`) into units of implementable work. This is a
deliberate deviation from the SDD process's decompose-everything-upfront
step: the architecture is large, early waves change the shape of later
ones (the fork's outcomes feed the SQLite engine tasks; the contract
suite's harness shape feeds both engines' verification work), and
decomposing only the next wave or two at a time keeps each session's
task set reviewable and lets later decompositions absorb earlier waves'
course corrections.

Rhythm: decompose a wave → implement it → review gate → decompose the
next wave. Task files live in `tasks/` (taskgraph-managed; frontmatter
carries the categorical estimates). Wave boundaries are also review
boundaries.

## The waves

Dependency logic in one line: core → (substrate fork ∥ postgres
engine) → sqlite engine → contract suite → mem engine → release
readiness. The substrate fork is contract-blind (ADR-012 §2), so it
needs only the workspace scaffold from wave 1; the Postgres engine
needs only the core crate. Waves 2 and 4 are therefore independent of
each other and could run in either order (or in parallel, if agents
are ever available in parallel). The mem engine (wave 6) needs the
core crate plus the finished suite (wave 5) — born pinned, per
[ADR-024](../architecture/decisions/024-mem-engine.md).

| Wave | Contents | Depends on | Status |
|---|---|---|---|
| [1](#wave-1--foundations) | Workspace scaffold; core crate (errors, value types, full trait surface); contract-suite scaffold | — | implemented + reviewed (2026-10-08) |
| [2](#wave-2--sqlite-substrate-fork) | honker-core fork into `alkstore-sqlite/src/substrate/`: port, deltas, provenance, test floor | wave 1 (workspace scaffold only) | implemented + reviewed (2026-10-08) |
| [3](#wave-3--sqlite-engine) | SQLite engine: connection architecture, re-derived queue ops on contract v1, scheduler/outbox, tx seam, SQLite backlog column | waves 1 + 2 | implemented + reviewed (2026-10-08) |
| 4 | [Postgres engine](#wave-4--postgres-engine): schema bootstrap, pool/open, listener/forwarder, all mechanisms, tx seam, pg backlog column | wave 1 | implemented + reviewed (2026-10-08) |
| 5 | [Contract suite](#wave-5--contract-suite): the cross-engine equivalence properties (core-contract.md §Verification backlog), version-stamped per ADR-017 | waves 3 + 4 | implemented + reviewed (2026-10-10) |
| 6 | [Mem engine](#wave-6--mem-engine): separate `alkstore-mem` crate, full contract v1 over in-memory mechanisms (tx overlay, queue/scheduler/streams/locks/wakes), the suite's third factory column (born pinned), wasm32 compile-clean acceptance | waves 1 + 5 | decomposed (2026-10-10) |
| 7 | [Release readiness](#wave-7--release-readiness): crate docs, deployment matrix final pass, README (written last, honestly), publish prep; fuzzing decision | wave 6 | not yet decomposed |

## Wave 1 — Foundations

The core crate is contract v1 in code: the error taxonomy (ADR-008 §5),
the value types (ADR-019 §3, ADR-020), the full trait surface
(ADR-008 §1–§3/§8, ADR-014, ADR-019, ADR-021), and the payload encoding
posture (ADR-020 §4). Nothing engine-specific lives here — no
resolution arithmetic, no SQL. The equal-jitter curve, opts-stamping
resolution, and boundary math are deliberately *not* core: ADR-012 §2
pins each engine as the owner of one implementation, with equivalence
pinned by the contract suite (wave 5).

The contract suite gets scaffolded now (not in wave 5) because its
harness shape — a `Store`-factory-parameterized property crate — is
easier to grow row by row as engines land than to retrofit onto two
finished engines. Wave 5 fills it with the cross-engine equivalence
rows; waves 3 and 4 adopt the harness for their own backlog columns.

## Wave 2 — SQLite substrate fork

The fork per ADR-011/012/013: port honker-core at `f4e53c6` into
`alkstore-sqlite/src/substrate/`, apply the three watcher port deltas
and the bootstrap re-keying, drop cron/experimental/cut-flag machinery,
re-own the table family as `__alkstore_*`, carry `PROVENANCE.md` and
the dual-license notice in-tree (ADR-018), and stand up the inherited
test suites as the floor. The substrate stays sync and contract-blind;
the engine layer that maps it onto the core contract is wave 3, not
here. Reviewability against the lineage (ADR-012 §3) is a property the
wave-2 review gate checks explicitly.

## Wave 3 — SQLite engine

The engine layer that maps the forked substrate onto the core
contract: the `open` constructor (connection architecture — writer
slot, reader pool, watcher spawn — per engine-sqlite.md), the
`spawn_blocking` seam, the full `Store`/`TxHandle`/mechanism-handle
trait impls over the substrate's ops, the scheduler leader loop and
outbox helper, and the engine's backlog column in the contract suite
(the ADR-023 rows among them, factory-parameterized so wave 5 runs
them against both engines).

The waves-1–2 general review
(`docs/reviews/001-waves-1-2-general-review.md`) and its
resolution ([ADR-023](../architecture/decisions/023-fourth-review-round.md))
shaped this wave's task set:

- **Already landed pre-decomposition** (commit `44637ee`, not wave-3
  tasks): `encode_payload` is fallible (`Result<Vec<u8>, Error::Codec>`,
  ADR-023 §1); `open_conn` drops `SQLITE_OPEN_URI` (§3, register
  D-29); the numeric-argument domain table is pinned in
  core-contract.md (§2); the 1 ms watcher default stands with the
  cadence documented in deployment.md (§4).
- **Folded into wave 3's tasks** (the review's §7 wiring items): the
  trait-impl extent/duration guards (the contract-side domain rule,
  enforced at the engine's trait-impl entry — the `sqlite-engine-*`
  tasks carry it per mechanism), the two `#![allow]` lint removals in
  `substrate/mod.rs` (the integration task — they can only lift once
  every substrate surface is wired), and `SqliteOpts::poll_interval`
  wiring (the constructor task).
- **Staying put as ordered**: M-1's retention-failure test and N-5's
  panic probe → wave 5's contract-suite rows; N-1's growth-posture
  review → wave 7.

## Wave 4 — Postgres engine

The second engine: the core contract implemented on tokio-postgres +
deadpool-postgres per engine-postgres.md — schema bootstrap (one
engine-owned schema, default `alkstore`, ADR-010 §8), the pool/open
constructor, the hand-rolled LISTEN forwarder (dedicated non-pooled
listener connection, bounded broadcast fanout, exponential-backoff
reconnect with re-LISTEN, the synthetic reconnect-wake on
`__alkstore_listener_reconnected__`), the full `Store`/`TxHandle`/
mechanism-handle trait impls (natively async — no `spawn_blocking`
seam; the tx handle holds the pooled object directly, ADR-007's pg
arm), the re-derived queue machinery (`FOR UPDATE SKIP LOCKED` claims,
LISTEN-driven wake with re-poll safety net), the scheduler leader loop
and outbox helper, and the engine's backlog column in the contract
suite (factory-parameterized; wave 5 runs the same rows against both
engines).

The wave is deliberately shaped as wave 3's structural twin — same
task rhythm (constructor → seam → mechanisms in parallel →
scheduler/outbox → integration → review gate) — because the two
engines implement the same contract and the wave-3 task set's
boundaries proved clean. The deltas are the engine's own: no
substrate (the pg machinery is re-derived greenfield per ADR-004/005,
with the pg-boss schema family as design reference), a natively-async
seam (Send+Sync client, POC #2 compile-probe), the forwarder as the
wake substrate (with its two POC-pinned deadlock pitfalls owned as
test-pinned failure modes), and the `PayloadTooLarge` client-side
check (this engine *produces* the variant — the one runtime carriage
of an engine asymmetry, ADR-016 §5).

Wave-3 outcomes absorbed into the task set:

- **The `#[doc(hidden)]` constructors** (`Job::from_row`,
  `StreamEvent::from_row`, `Schedule::new`, `Wake::new`) already
  exist — wave 3's pre-work task built them engine-agnostically; wave
  4 consumes them as-is (no wave-4 equivalent needed).
- **The engine-side arithmetic is re-owned, not shared**: the
  equal-jitter backoff curve, the opts-resolution rules
  (delay-over-`run_at`, relative-`expires`, the derived stamp sets
  300/3/5/none and 60/5/5), and the outbox backing-queue derivation
  are each engine's own implementation (ADR-012 §2's one-owner rule
  applied per engine); the pg tasks re-implement them from the ADR
  text, and the contract suite (wave 5) pins the two engines'
  arithmetic to identical outputs. The SQLite engine's `resolution.rs`
  is reference, not a dependency.
- **The `@every` spec grammar has no shared parser on this side** —
  the SQLite engine reuses the substrate's `parse_every_interval`
  (one-line delta D-31's neighbor); the pg engine owns its parser
  (the grammar is small and pinned: `@every <n><unit>`, `s|m|h|d`).
  Equivalence of *behavior* (what fires, when) is suite-pinned; the
  parsers themselves are per-engine.
- **The wave-3 review's deferred notes** (reader-pool close path,
  commit-error-arm coverage) stay SQLite-scoped — the pg engine's
  pool is deadpool-managed (no hand-rolled close path to review) and
  its commit-error arm gets coverage in the pg tasks' own tests.
- **The suite's factory contract** (isolation + idempotent teardown)
  is what the pg factory implements — a fresh schema per `open` per
  the SQLite factory's precedent (fresh temp file there); the
  POC's shared-server parallel-interference caveat (findings,
  invocation note) is answered by exactly that isolation, not by
  sequential-only harnesses.

Test posture: the engine's tests need a live Postgres server. The
harness convention is the POC's (dockerized `postgres:16-alpine` on
:15432, the `pglo-poc` container — still running in the dev
environment); connection settings ride environment/config, never
hardcoded. Tests that cannot reach a server skip cleanly (the
`SKIP`-posture), so the workspace gates stay green server-less — but
the wave's acceptance requires the suite green *against* the server.

One design point the architecture leaves to implementation (pinned in
the wave-4 tasks, flagged here for visibility): **the queue/stream
wake-channel naming**. The contract pins LISTEN as the pg wake
trigger and pins the channels/queues shared namespace, but no doc
names the channel an enqueue/publish notifies on. The tasks pin the
natural realization — the mechanism name *is* the wake channel
(`listen(queue_name)` receives that queue's enqueue wakes; same for
streams), legal by construction under the shared namespace — with
the reserved reconnect-wake channel staying the only reserved string.

## Wave 5 — Contract suite

Filling the scaffolded suite (`alkstore-contract-suite`) with the
remaining verification-backlog rows and running the compatibility
gate. Waves 3 and 4 each landed a nine/ten-row backlog column; the
wave-5 decomposition started from an audit of what those columns
already discharge versus what the backlog still lacks.

**Already discharged by the engines' columns** (the wave-5 review
gate verifies each claim by reading the pinning row, not by trusting
the audit): name validation (the exemplar, incl. `schedule()`'s
queue-argument validation), the numeric-domain rows (extents +
durations), `encode_payload` typed failure + round-trip, the
`PayloadTooLarge` occurrence asymmetry (both engine-scoped arms),
drop-=-rollback no-ghosts, in-tx read-your-own-writes (which also
discharges the `save_offset_tx` exactly-once backlog row across
itself and the drop-rollback row), receiver close/save arms + monotone
composition (both columns), and — pinned engine-side rather than as
suite rows, per the sqlite-engine-integration task's scoping call —
plain-path SQLite open and the watcher-cadence knob
(`open_tests.rs`; SQLite-scoped backlog rows).

**Wave 5's task set** (the gaps):

- Queue depth: the job-handle validity predicate, the ADR-010 depth
  properties (reclaim-eats-attempt, dead-letter moves, the
  no-stranded-rows sweep), and M-1's retention-failure pin
  (`suite-queue-depth-rows`).
- Scheduler: boundary fires, bounded catch-up, leadership discipline —
  with a documented extension of the suite's determinism posture to
  admit runner-driving rows (`suite-scheduler-rows`).
- Tx seam: `outbox_enqueue_tx` and `publish_with_key_tx`
  commit-atomicity, plus N-5's `with_tx` panic-disposition probe —
  the panic path pinned against real engines for the first time
  (`suite-tx-commit-atomicity-rows`).
- Streams: the cross-engine ordering-equivalence row and the full
  `trim_to` semantics row (`suite-stream-rows`).
- Locks: TTL/expiry re-acquisition and the concurrent-`try_lock`
  loser posture — the SQLite busy-path is the open question the row
  exists to answer (`suite-lock-rows`).
- Wakes: the pinned `WakeReceiver` shapes, tolerance-bounded
  (`suite-wake-rows`).
- Arithmetic equivalence: the backoff-curve row and the two
  wall-clock-adjacent opts-resolution legs the existing row deferred
  to this wave (`suite-opts-backoff-rows`).
- Engine-side hardening riding the window: the wave-3 review's
  deferred SQLite commit-error-arm coverage (`sqlite-commit-error-arm`)
  and F-1's defense-in-depth candidates — explicitly not load-bearing
  since `pg-fix-tx-wake` retired the flake's root cause
  (`pg-suite-infra-hardening`).
- The review gate (`review-wave-5`): the backlog discharge audit,
  stamp verification, green-on-both-engines, the parked-disposition
  audit — and the gate that flips `engine-sqlite.md` /
  `engine-postgres.md` to `stable`.

Judgment calls the decomposition parked in task Notes (the review
gate audits each): where the M-1 retention-failure pin, the
beyond-64-cap skip-forward leg, and the backoff 1-hour-cap leg land
when the public surface cannot express them (engine-side is the
expected answer, recorded per case); whether the scheduler rows
demand the pg fire-wake parity the wave-4 fix-batch gate recorded;
and what the SQLite lock busy-path actually returns under contention.

## Wave 6 — Mem engine

The third engine ([ADR-024](../architecture/decisions/024-mem-engine.md),
2026-10-10): a separate `alkstore-mem` crate implementing the full
contract v1 over guarded in-memory mechanisms — the honest-ephemeral
tier (no durability, single-process, ephemeral by design, never
fleet-valid), adopted for the wasm/sandbox and downstream-adapter
economics the consumer inventory's engine-tier row records
(operator-authority, 2026-10-10 — the row-first gate satisfied before
this wave was assumed). Release readiness moved to wave 7.

The wave's shape mirrors the engine waves' rhythm: constructor + tx
overlay → mechanisms in parallel → scheduler/outbox → suite
integration → review gate. What mem carries: the queue state machine
(visibility/reclaim/dead-letter/sweep), scheduler boundaries +
catch-up + leadership (trivially owned single-instance, still run —
engine-uniform per ADR-009 §4), streams with per-consumer offsets and
trim, TTL locks, wakes. What it does not carry: no pooling, no schema
bootstrap, no forwarder, no `spawn_blocking` seam, no reconnection
concept — the distributed machinery that made wave 4 build-heavy
doesn't exist here. The wave is estimated at pg-wave scale or
somewhat smaller.

The load-bearing artifact is the **tx overlay**: `*_tx` effects stage
in a handle-private overlay; commit merges it atomically and fires
the overlay's pending wakes; drop discards it — read-your-own-writes
easy, drop-=-rollback trivial, and *wake-at-commit* structural. That
last property is the seam review 002 found broken pg-side
(`pg-fix-tx-wake`); mem gets it pinned from birth by the suite's
existing tx-commit-atomicity rows.

Born pinned: [ADR-022](decisions/022-contract-suite-layout.md)'s
`StoreFactory` is reused verbatim as a third factory column wired
onto already-authored, version-stamped rows — no re-derivation. The
engine re-owns its own copies of the backoff curve, opts resolution,
and the `@every` parser ([ADR-012](decisions/012-forked-substrate-design.md)
§2's one-owner rule, third owner); the suite now pins that arithmetic
three-way.

**Acceptance items** ([ADR-024](../architecture/decisions/024-mem-engine.md)
§5): the crate compiles clean for `wasm32-unknown-unknown` (target
already installed in the dev environment); workspace host gates stay
green; the suite's mem column passes on the host, run under a
**current-thread runtime flavor** — the test that keeps internals
wasm-clean (no `spawn_blocking`, tokio sync + time only). The
current-thread flavor rides one harness pre-task: the suite's
`past_stamp_sleep` blocking sleep (review 003's posture note at
`properties.rs:1683`) becomes an async sleep — the only suite-side
change the wave carries. Running the suite itself *on* the wasm
target is scoped out with a named collapse condition (a
wasm-bindgen-test adapter crate) — a scope decision recorded in
ADR-024 §5, not a pending-client hedge.

Deliverables beyond code: `engine-mem.md` (the spec — drafted with
this wave's adoption), the deployment matrix's mem rows (landed with
ADR-024), and the mem factory's suite wiring.

Riding the window: review 003's Finding 1 (the pg scheduler
transient-error retry loop, MEDIUM — engine-side, small,
mem-independent); Findings 2–3 follow their park recommendation into
wave 7's pre-release pass.

**Wave 6's task set** (the decomposition, 2026-10-10 — the pg wave's
rhythm: foundations → seam → mechanisms in parallel → scheduler/outbox
→ integration → review gate):

- `mem-engine-foundations` — crate scaffold (core + tokio sync+time
  only), `MemStore::new()` isolation, guarded state core, wake-routing
  substrate, clock accessor; the wasm32 compile gate starts here and
  stays green onward.
- `mem-engine-seam-tx` — the load-bearing task: the tx overlay (all
  eleven `*_tx` staged, commit-merge + wake-at-commit, drop =
  discard, `with_tx` panic posture) + the `Store` trait surface +
  entry-point numeric-domain guards (`suite-tx-commit-atomicity-rows`
  is what consumes it once integrated).
- `mem-engine-notify-listen` — channels wake substrate surface,
  three recv forms, close-at-engine-drop, no-replay, never coalesced;
  depends on the seam (tx-staged notify).
- `mem-engine-queues` — the ADR-010 state machine driver-free;
  equal-jitter curve and opts resolution as the third owner.
- `mem-engine-streams` — in-memory log, per-consumer offsets,
  `trim_to`, receiver arms.
- `mem-engine-locks` — TTL registry; the SQLite busy-path question
  has no mem analog (loser is a clean `None`).
- `mem-engine-scheduler-outbox` — tick/boundary/catch-up/leadership
  through the reserved scheduler lock; outbox over queues.
- `suite-harness-current-thread` — the wave's one suite-side pre-task
  (async `past_stamp_sleep`); engine-independent, required before the
  mem column's current-thread flavor.
- `mem-engine-integration` — full-surface wiring, the suite's third
  `StoreFactory` column green on host under the current-thread
  flavor, the wasm32 acceptance items, `engine-mem.md` to
  implementation-complete.
- `pg-fix-scheduler-tick-seam` — review 003 Finding 1, riding the
  window (engine-side, mem-independent; the last uncovered wave-4
  hardening arm).
- `review-wave-6` — the born-pinned gate: conformance read, third-
  column discharge audit, wasm acceptance audit, spec disposition;
  depends on integration + the rider so the window closes everything.

Parallelism note: the foundation task blocks the seam; the seam blocks
the mechanisms; the mechanisms are mutually parallel. The suite pre-task
and the Findings-1 rider are independent of the mem chain entirely and
can run any time in the window (the rider must close before the gate).

## Wave 7 — Release readiness

The original wave 6, renumbered when the mem engine inserted at wave
6 ([ADR-024](../architecture/decisions/024-mem-engine.md)): crate
docs, the deployment matrix final pass (across all three engines now),
the crate README (written last, honestly), publish prep, N-1's
growth-posture review — and the **fuzzing decision** (the
alksocks/alktty/alktunnels pattern), the one remaining
decided-at-implementation deferral. Decomposes after wave 6's review
gate, with review 003's Findings 2–3 riding the pre-release pass, and
the wave-5 gate's flake-watch flag carried
(`tasks/review-wave-5.md` §Notes 6 — the two unreproducible pg row
failures; if either reproduces, a dedicated investigative session
before any postulate-and-fix).

## Decided points

- **Contract-suite layout — option (a)**: a small internal
  `alkstore-contract-suite` crate (not published) exposing property
  tests parameterized over a `Store` factory; each engine crate takes
  it as a dev-dependency. One normative owner per property, mirroring
  ADR-012 §2's one-owner rule. This discharges ADR-017 §4.2's
  "decided at implementation" deferral; recorded as ADR-022 by the
  scaffold task.
- **Engine tests vs. contract suite**: each engine wave carries its own
  mechanism tests (does the engine work); wave 5 carries the
  cross-engine *equivalence* properties (do the engines agree). The
  verification-backlog rows are mostly equivalence-shaped, so this
  split keeps wave 5 from re-testing engine internals.
- **CI**: none, deliberately. CI and publishing are run manually
  (self-hosted Gitea; supply-chain posture). No CI-wiring task exists;
  the merge gates (`cargo test`, `cargo clippy --all-targets --
  -D warnings`, `cargo fmt --check`) are run coordinator-side.
- **Mem engine** (ADR-001 §4): **decided 2026-10-10, pre-decomposition
  ([ADR-024](../architecture/decisions/024-mem-engine.md))** — a
  separate `alkstore-mem` crate, full contract v1, honest-ephemeral
  posture, wasm32 compile-clean acceptance; wave 6, with release
  readiness renumbered to wave 7. The deferral discharged: its
  collapse condition ("implementation time") was reached early via
  the consumer pause + the wasm/sandbox motivation, with the row-first
  gate satisfied by the consumer inventory's engine-tier row
  (operator-authority, 2026-10-10).
- **Fuzzing adoption** (the alksocks/alktty/alktunnels pattern):
  remains the one decided-at-implementation deferral, recorded here
  so it surfaces as an explicit decision point in wave 7 (per
  AGENTS.md's no-fuzzing posture, revisit only if a task or ADR
  introduces it). Renumbered from wave 6 together with the mem
  decision's move.

## Review gates

Each wave ends in a review task (`review-wave-N`) before the next wave
decomposes. Specific gates:

- **Wave 1 review** — the trait surface is versioned contract surface
  from the first release (ADR-017); a shape error found here is cheap,
  found in wave 5 it is a migration. Review checks the code against the
  pinned ADR text line by line.
- **Wave 2 review** — diff reviewability against the honker lineage
  (ADR-012 §3's fidelity posture), provenance register completeness
  (ADR-018), floor tests green.
- **Wave 3/4 reviews** — engine-vs-contract conformance; the backlog
  columns each engine owns.
- **Wave 5 review** — the suite as compatibility instrument: every
  backlog row present, version-stamped, green on both engines; this is
  the gate that flips the engine specs to `stable`.
- **Wave 6 review** — mem-engine-vs-contract conformance (the
  born-pinned gate): the suite's third column green on the host, the
  wasm32 compile gate clean, the current-thread-flavor column run
  (harness pre-task disposed), the engine's own mechanism tests, and
  the `engine-mem.md` spec read against the pinned ADR-024 text —
  the gate that flips the mem spec toward `stable`.

## Review rounds so far

- **Wave 1 review gate** (`review-wave-1`) — trait surface vs pinned
  ADR text; validation coverage fixes landed.
- **Wave 2 review gate** (`review-wave-2`) — lineage diff clean, one
  re-derivation defect found and fixed (D-27).
- **General review, waves 1–2** (2026-10-08,
  `docs/reviews/001-waves-1-2-general-review.md`) — M-1 fixed
  inline (sweep savepoint scope); M-2/N-2/N-4/N-6 resolved as ADR-023
  pre-decomposition; lint removal + suite adds folded into waves 3/5;
  N-1 recorded for release readiness (now wave 7).
- **Wave 3 review gate** (`review-wave-3`) — engine-vs-contract
  conformance code-read clean; two findings fixed inline (the
  `open_writer_connection` boundary move out of `substrate/mod.rs`;
  the writer-slot error-arm stranding in
  `with_writer`/`begin`/`commit`); two minor notes deferred to
  wave 5/6 (reader-pool close path, commit-error-arm coverage).
- **Wave 4 review gate** (`review-wave-4`) — engine-vs-contract
  conformance code-read clean (0 findings); the flagged
  `tx_publishes_compose_with_the_handle` flake reproduced twice and
  recorded as F-1 (test-infra, wake-subscription under load — root
  cause unresolved at gate time; candidate dispositions in the task's
  Notes for wave 5's suite hardening); three no-action notes
  (F-2..F-4). F-1's root cause was later found engine-side by the
  general review below and retired by `pg-fix-tx-wake`.
- **General review, wave 4** (2026-10-09,
  `docs/reviews/002-wave-4-general-review.md`) — two live-proven
  consumer-facing bugs (the forwarder's permanent death after one
  failed reconnect — an untested failure arm the gate's test never
  covered; the tx enqueue/publish paths' missing `pg_notify` wake —
  F-1's root cause, engine-side), a `max_size: 0` open-hang, two
  narrow robustness gaps, doc mismatches, decode-duplication smells.
  Fixes recommended before wave 5 decomposes. The tx-wake fix landed
  (`pg-fix-tx-wake`, 2026-10-09): the tx producer paths now wake
  commit-atomically, retiring F-1's engine arm (record updated in
  `tasks/review-wave-4.md`) and making `tx_publishes_compose_with_the_handle`
  deterministic (20 consecutive solo runs green); the remaining fixes
  ride the wave-4 fix-batch decomposition below.
- **Wave 5 review gate** (`review-wave-5`, 2026-10-10) — the suite as
  compatibility instrument, gate passed: the backlog discharge map
  verified row-by-row against the pinning tests (all 25 mechanism rows
  per column stamped, wiring confirmed in both engines' suite targets;
  the engine-side pins — SQLite open row, watcher-cadence knob, M-1
  sweep-rollback (SQLite trigger seam + the pg frame's code-read),
  beyond-64 skip-forward, cap-curve — read and confirmed); stamps
  cross-checked against the cited ADR § texts (the
  `enqueue_opts_resolution` amendment accumulation rides ADR-023 §2 per
  the convention); parked dispositions audited (all six recorded;
  scheduler fire-wake parity left as-is, the lock busy-path answered
  with no divergence); green on both engines (SQLite server-less; pg
  vs the harness server, three full runs incl. one concurrent with the
  SQLite column, plus focused stress). Engine specs flipped to
  `stable`. Two unreproducible pg row failures from development were
  recorded in the task's Notes (both rows' assertions are
  state-outcome-shaped; flagged for watch, not blocking the gate) —
  see `tasks/review-wave-5.md` §Notes.
- **Wave 5 decomposition** (2026-10-10) — audit-first: the engines'
  backlog columns already discharge most of the §Verification backlog
  (map recorded in `tasks/review-wave-5.md`'s appendix for the gate to
  verify); the wave fills the gaps with seven suite-row tasks grouped
  by mechanism, two engine-side hardening tasks, and the gate. See the
  Wave 5 section.
- **Wave 4 decomposition** (2026-10-08) — shaped as wave 3's
  structural twin; wave-3 outcomes absorbed (constructors exist;
  arithmetic re-owned per engine; per-engine `@every` parser;
  SQLite-scoped deferred notes stay put). See the Wave 4 section.
- **Wave 6 decomposition** (2026-10-10) — ADR-024 adopted the mem
  engine the same day the wave-5 gate closed; the task set follows the
  pg wave's rhythm with the tx overlay as the load-bearing task, the
  suite's third column as the born-pinned deliverable, the harness's
  async-sleep pre-task, and review 003 Finding 1 riding the window.
  See the Wave 6 section.
- **Wave-5 residue decomposition** (2026-10-10) — the wave-5 review's
  outstanding items audited post-gate: the one recorded "for a later
  task" gap (scheduler fire-wake latency parity) decomposed as
  `pg-fix-scheduler-fire-wake` (pre-wave-6, standalone); the flake-watch
  flag carried into the wave-7 section above; review 003's Finding 1
  already decomposed (`pg-fix-scheduler-tick-seam`, the wave-6 rider)
  and Findings 2–3 already parked to wave 7. See the Wave 7 section for
  the watch carriage.
- **Wave-5 residue closure** (2026-10-10) — the remaining
  "recorded for a later task" item landed: `pg-fix-scheduler-fire-wake`
  closed the scheduler fire-wake latency-parity gap (the tick's
  in-tx fires now issue their commit-atomic `pg_notify` wake, one
  coalesced wake per firing schedule per tick); the three gap records
  (`review-wave-4-fixes`'s recorded-for-later note, `suite-scheduler-rows`'s
  disposition note + Notes bullet, `review-wave-5` §Notes 4's audit row)
  retired with pointers, keeping the mem engine's fire posture written
  against a closed gap before wave 6.
- **Wave-4 fix-batch decomposition** (2026-10-09) — the general
  review's findings decomposed into seven `pg-fix-*` tasks + a
  `review-wave-4-fixes` gate: Finding 1 → `pg-fix-forwarder-reconnect`
  (with the failed-connect test seam the gate's blind spot demands),
  Finding 2 → `pg-fix-tx-wake` (retires F-1's engine arm), Finding 3
  + the DSN-options note → `pg-fix-open-path`, Finding 4 →
  `pg-fix-stale-unlisten`, Finding 5 + the scheduler doc fix →
  `pg-fix-scheduler-resilience`, the decode-duplication smell + small
  cleanups → `pg-fix-dedupe-cleanup`, the TLS/QueueOpts doc
  alignments → `pg-fix-docs-alignment`. Sequencing per the review's
  recommendation: **wave 5 decomposes after the two HIGH fixes land**
  (the suite's wake-driven rows would otherwise inherit a hang-shaped
  false failure); 3–7 may trail into wave 5's window if the
  fix-batch gate judges them wake-independent.