From 5abd351c86d6d0b0a761f3bf199ccaeb5dc3f1de Mon Sep 17 00:00:00 2001
From: "glm-5.3-flash" <glm-5.3-flash@alk.dev>
Date: Sat, 10 Oct 2026 09:57:01 +0000
Subject: [PATCH] =?UTF-8?q?Wave-6=20decomposition=20(mem=20engine):=20elev?=
 =?UTF-8?q?en=20tasks=20per=20the=20pg-wave=20rhythm=20=E2=80=94=20foundat?=
 =?UTF-8?q?ions=20(crate=20scaffold,=20MemStore::new=20isolation,=20guarde?=
 =?UTF-8?q?d=20state=20core,=20wake=20routing,=20wasm32=20gate=20from=20bi?=
 =?UTF-8?q?rth),=20seam-tx=20(the=20load-bearing=20tx=20overlay:=20eleven?=
 =?UTF-8?q?=20staged=20=5Ftx=20methods,=20commit-merge=20+=20wake-at-commi?=
 =?UTF-8?q?t=20=E2=80=94=20pg-fix-tx-wake's=20discipline=20structural=20fr?=
 =?UTF-8?q?om=20the=20start,=20drop=20=3D=20discard=20trivial,=20with=5Ftx?=
 =?UTF-8?q?=20panic=20posture),=20mechanisms=20mutually=20parallel=20(noti?=
 =?UTF-8?q?fy-listen=20close-at-engine-drop/no-replay/never-coalesced;=20q?=
 =?UTF-8?q?ueues=20=3D=20ADR-010=20machine=20driver-free=20with=20the=20eq?=
 =?UTF-8?q?ual-jitter=20curve=20and=20opts=20resolution=20as=20ADR-012=20?=
 =?UTF-8?q?=C2=A72's=20third=20owner;=20streams=20log+offsets+trim;=20lock?=
 =?UTF-8?q?s=20TTL=20registry,=20no=20busy-path=20analog),=20scheduler-out?=
 =?UTF-8?q?box=20(tick/catch-up-64/leadership=20through=20the=20=5F=5Falks?=
 =?UTF-8?q?tore=5Fscheduler=20lock,=20engine-uniform=20per=20ADR-009=20?=
 =?UTF-8?q?=C2=A74;=20outbox=20over=20queues=20with=20the=2060/5/5=20seam?=
 =?UTF-8?q?=20stamp),=20integration=20(suite=20third=20StoreFactory=20colu?=
 =?UTF-8?q?mn=20green=20on=20host=20under=20a=20current-thread=20flavor,?=
 =?UTF-8?q?=20wasm32=20acceptance=20items,=20engine-mem.md=20to=20implemen?=
 =?UTF-8?q?tation-complete),=20and=20the=20review-wave-6=20gate=20(born-pi?=
 =?UTF-8?q?nned=20audit:=20conformance=20read,=20discharge-map=20wiring,?=
 =?UTF-8?q?=20wasm=20items,=20three-way=20equivalence=20green,=20class-1?=
 =?UTF-8?q?=20window=20discipline).=20Window=20riders:=20suite-harness-cur?=
 =?UTF-8?q?rent-thread=20=E2=80=94=20the=20wave's=20one=20suite-side=20pre?=
 =?UTF-8?q?-task,=20past=5Fstamp=5Fsleep's=20blocking=20sleep=20goes=20asy?=
 =?UTF-8?q?nc=20per=20review=20003's=20properties.rs:1683=20posture=20note?=
 =?UTF-8?q?,=20enabling=20the=20current-thread=20flavor;=20pg-fix-schedule?=
 =?UTF-8?q?r-tick-seam=20=E2=80=94=20review=20003=20Finding=201,=20the=20c?=
 =?UTF-8?q?fg(test)=20transient-fault=20seam=20driving=20the=20real=20tick?=
 =?UTF-8?q?=5Fwith=5Fretries=20through=20retry-then-success=20and=20exhaus?=
 =?UTF-8?q?tion=20arms=20(the=20last=20uncovered=20wave-4=20hardening=20ar?=
 =?UTF-8?q?m,=20sqlite-commit-error-arm=20pattern).=20Task=20hygiene:=20pg?=
 =?UTF-8?q?-fix-open-path=20frontmatter=20fixed=20(unquoted=20'max=5Fsize:?=
 =?UTF-8?q?=200'=20colon-space=20inside=20the=20name=20scalar=20broke=20YA?=
 =?UTF-8?q?ML=20parsing=20=E2=80=94=20taskgraph=20validate=20had=20been=20?=
 =?UTF-8?q?red=20one-error=20since=20the=20wave-4=20fix-batch=20decomposit?=
 =?UTF-8?q?ion;=20also=20restores=20review-wave-4-fixes'=20dependency=20re?=
 =?UTF-8?q?solution).=20implementation.md:=20wave-6=20table=20row=20?=
 =?UTF-8?q?=E2=86=92=20decomposed,=20task-set=20listing=20with=20the=20par?=
 =?UTF-8?q?allelism=20note=20(rider=20+=20pre-task=20independent=20of=20th?=
 =?UTF-8?q?e=20mem=20chain;=20rider=20closes=20before=20the=20gate),=20wav?=
 =?UTF-8?q?e-6=20decomposition=20bullet=20in=20the=20review-rounds=20recor?=
 =?UTF-8?q?d.=20Docs-only=20change;=20verified=20taskgraph=20validate=20(6?=
 =?UTF-8?q?0=20tasks,=20no=20cycles),=20cargo=20fmt=20--check,=20cross-ref?=
 =?UTF-8?q?erence=20read?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/plans/implementation.md          | 58 ++++++++++++++--
 tasks/mem-engine-foundations.md       | 92 ++++++++++++++++++++++++++
 tasks/mem-engine-integration.md       | 95 +++++++++++++++++++++++++++
 tasks/mem-engine-locks.md             | 65 ++++++++++++++++++
 tasks/mem-engine-notify-listen.md     | 73 ++++++++++++++++++++
 tasks/mem-engine-queues.md            | 86 ++++++++++++++++++++++++
 tasks/mem-engine-scheduler-outbox.md  | 87 ++++++++++++++++++++++++
 tasks/mem-engine-seam-tx.md           | 95 +++++++++++++++++++++++++++
 tasks/mem-engine-streams.md           | 80 ++++++++++++++++++++++
 tasks/pg-fix-open-path.md             |  2 +-
 tasks/pg-fix-scheduler-tick-seam.md   | 68 +++++++++++++++++++
 tasks/review-wave-6.md                | 81 +++++++++++++++++++++++
 tasks/suite-harness-current-thread.md | 62 +++++++++++++++++
 13 files changed, 939 insertions(+), 5 deletions(-)
 create mode 100644 tasks/mem-engine-foundations.md
 create mode 100644 tasks/mem-engine-integration.md
 create mode 100644 tasks/mem-engine-locks.md
 create mode 100644 tasks/mem-engine-notify-listen.md
 create mode 100644 tasks/mem-engine-queues.md
 create mode 100644 tasks/mem-engine-scheduler-outbox.md
 create mode 100644 tasks/mem-engine-seam-tx.md
 create mode 100644 tasks/mem-engine-streams.md
 create mode 100644 tasks/pg-fix-scheduler-tick-seam.md
 create mode 100644 tasks/review-wave-6.md
 create mode 100644 tasks/suite-harness-current-thread.md

diff --git a/docs/plans/implementation.md b/docs/plans/implementation.md
index 9c6ffa2..c41f6b8 100644
--- a/docs/plans/implementation.md
+++ b/docs/plans/implementation.md
@@ -1,8 +1,9 @@
 ---
 status: draft
-last_updated: 2026-10-10 (ADR-024 — the mem engine adopted as wave 6
-and decomposed-in-place documentation; release readiness renumbered
-to wave 7. Waves 1–5 implemented and reviewed; engine specs stable.)
+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.)
 ---
 
 # alkstore — Implementation plan
@@ -41,7 +42,7 @@ core crate plus the finished suite (wave 5) — born pinned, per
 | [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 | not yet decomposed |
+| 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
@@ -311,6 +312,49 @@ 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
@@ -446,6 +490,12 @@ decomposes. Specific gates:
   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-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`
diff --git a/tasks/mem-engine-foundations.md b/tasks/mem-engine-foundations.md
new file mode 100644
index 0000000..7e0bdc3
--- /dev/null
+++ b/tasks/mem-engine-foundations.md
@@ -0,0 +1,92 @@
+---
+id: mem-engine-foundations
+name: Mem engine — crate scaffold, `MemStore::new()`, guarded state core, wake routing
+status: pending
+depends_on: []
+scope: moderate
+risk: medium
+impact: component
+level: implementation
+tags: [wave-6, mem-engine]
+---
+
+## Description
+
+The mem engine's foundations (wave 6 — [ADR-024](../architecture/decisions/024-mem-engine.md)):
+a new workspace member `alkstore-mem` and the state core every later
+task builds on.
+
+- **Crate + manifest**: workspace member per
+  [ADR-024](../architecture/decisions/024-mem-engine.md) §1 —
+  dependencies are `alkstore` (versioned path pin per
+  [ADR-017](../architecture/decisions/017-contract-versioning.md) §4.1,
+  matching the other engines' manifests) plus tokio restricted to the
+  **wasm-supported subset (sync + time only)**. No driver
+  dependencies. `thiserror` via core; no other crates.io surface.
+- **Constructor**: `MemStore::new()` — engine-native, no connection
+  string, no file path (the one documented exception to the
+  core-contract open prose, amended by
+  [ADR-024](../architecture/decisions/024-mem-engine.md) §4). Each
+  `new()` yields a fully isolated instance sharing nothing (the suite
+  factory's isolation contract); teardown is drop. No `PgOpts`-equivalent
+  opts struct exists — nothing to configure (if a knob surfaces during
+  the wave, `MemOpts` with `..Default::default()` follows the family
+  opts pattern; not assumed now).
+- **Guarded per-mechanism state core**: the store instance is the
+  state — per-mechanism structures (queues+jobs, dead letters,
+  streams+offsets, locks, schedules) behind the family's locking
+  discipline (parking_lot short-held internal locks per AGENTS
+  convention 3; tokio primitives for cross-await coordination).
+  Layout is module-per-file under `src/`, mirroring the other
+  engines. Subsequent mechanism tasks own their tables' shapes; this
+  task owns the shared scaffolding: the guarded-state container idiom,
+  name validation at entry (same `InvalidName`/`ReservedName` rules as
+  every other engine — reserved prefix `__alkstore_`, the one
+  reserved string `__alkstore_listener_reconnected__` unused here but
+  still rejected), and the wake-routing substrate (in-process channels;
+  a mechanism registers its commit-ordered wake source, receivers
+  attach per channel).
+- **Wake substrate shape**: no batching boundary exists — wakes
+  deliver at the commit boundary directly to each open receiver,
+  per-subscriber FIFO by commit order (engine-mem.md §Architecture;
+  coalescing not applicable). The routing core lives here; the
+  `listen()`/`WakeReceiver` surface lives in `mem-engine-notify-listen`.
+- **Clock posture**: every timestamp (unix-seconds stamps, visibility
+  deadlines, TTLs, scheduler boundaries) reads the process clock —
+  there is no server clock to defer to. Keep the clock behind one
+  internal accessor so tests can observe timestamps deterministically
+  the same way the SQL engines' row shapes do.
+
+The `Store` trait impl itself is ADR-007-shaped and lands in
+`mem-engine-seam-tx` (the tx overlay is the load-bearing half);
+this task lands everything up to the trait boundary.
+
+## Acceptance Criteria
+
+- [ ] `alkstore-mem` is a workspace member compiling clean; manifest
+      dependency surface is core + tokio (sync + time) only
+- [ ] `MemStore::new()` constructs; two instances share nothing
+      (pinned by a unit test)
+- [ ] The guarded state core, validation rules, wake-routing
+      substrate, and clock accessor exist with unit pins
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean from this task onward (tokio subset discipline enforced
+      here, not retro-fitted)
+- [ ] Workspace gates green (`cargo build`, `cargo test`, clippy
+      `-D warnings`, fmt)
+
+## References
+
+- docs/architecture/decisions/024-mem-engine.md §1/§4
+- docs/architecture/engine-mem.md §Identity and posture, §Architecture
+- docs/architecture/core-contract.md §Naming / reserved namespace
+- tasks/pg-engine-schema.md (the wave-4 rhythm this wave mirrors — its
+  "foundations first" slot)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/mem-engine-integration.md b/tasks/mem-engine-integration.md
new file mode 100644
index 0000000..0186d71
--- /dev/null
+++ b/tasks/mem-engine-integration.md
@@ -0,0 +1,95 @@
+---
+id: mem-engine-integration
+name: Mem engine — integration (full-surface wiring, suite third column, wasm32 acceptance)
+status: pending
+depends_on: [mem-engine-notify-listen, mem-engine-streams, mem-engine-queues, mem-engine-locks, mem-engine-scheduler-outbox, mem-engine-seam-tx, suite-harness-current-thread]
+scope: moderate
+risk: medium
+impact: phase
+level: implementation
+tags: [wave-6, mem-engine, integration]
+---
+
+## Description
+
+The integration task: wire the finished mechanisms into a complete
+`Store`, adopt the contract suite as the third column, and carry the
+wasm acceptance items through ([ADR-024](../architecture/decisions/024-mem-engine.md)
+§5; the born-pinned posture — engine-mem.md §Isolation and the suite
+factory):
+
+- **Full-surface wiring**: every handle constructible off one
+  `MemStore`; trait-object plumbing; crate docs (module docs + a
+  crate-level doc carrying the honest-ephemeral posture statement —
+  no durability, single-process, ephemeral by design, never
+  fleet-valid, per [ADR-024](../architecture/decisions/024-mem-engine.md)
+  §2 — and the wasm identity line per engine-mem.md §Identity).
+- **Suite third column**: a `tests/contract_suite.rs` target
+  implementing `StoreFactory` (fresh `MemStore::new()` per run,
+  teardown = drop — the factory's isolation contract verbatim) and
+  running the shared rows wired per engine: mem's column carries the
+  mechanism rows that express on it and omits the engine-shaped rows
+  that cannot (reconnect-wake, watcher-death close, watcher-cadence —
+  the per-engine wiring the suite's rows already use;
+  `PayloadTooLarge`'s non-occurrence arm *wires* — the arm is the
+  pin). The column runs under a **current-thread runtime flavor**
+  (the pre-task's async-sleep harness makes this clean).
+- **wasm32 acceptance**: `cargo check --target wasm32-unknown-unknown
+  -p alkstore-mem` (and the workspace's other crates untouched)
+  clean; the manifest's tokio features verified as the sync+time
+  subset. On-target suite execution stays scoped out (the named
+  collapse condition — a wasm-bindgen-test adapter crate — recorded in
+  the task Notes at completion, not an OQ).
+- **No `spawn_blocking` anywhere**: grep-verified; internals
+  current-thread-clean by construction, now proven by the flavor the
+  column runs under.
+- Suite column green is the wave's center-of-mass: 25 rows' worth of
+  contract v1 assertions against a third, independent implementation —
+  any red row is either a mem defect or (if the row pins
+  implementation detail a correct engine could fail) a found suite
+  defect to raise with the reviewer *before* editing the row (rows pin
+  ADR text; a wobble is amend-in-place material under the class-1
+  window).
+
+## Acceptance Criteria
+
+- [ ] `StoreFactory` implemented for the mem engine; the third suite
+      column wired and **green on the host** (same row set per the
+      wiring table above)
+- [ ] The column runs under the current-thread flavor; no blocking
+      calls in mem internals (grep-verified)
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean
+- [ ] `engine-mem.md` updated from `draft`-initial to
+      implementation-complete (the spec grows with the wave per its
+      frontmatter note); crate docs carry the posture + wasm identity
+- [ ] Workspace gates green; clippy `-D warnings`; fmt clean
+- [ ] The class-1 window discipline respected: any suite-row change
+      or contract wobble surfaced to the reviewer, not silently
+      patched
+
+## Dependencies note
+
+`mem-engine-seam-tx` is listed because the overlay's commit-merge and
+`*_tx` read shapes are what the suite's tx rows exercise on mem; the
+mechanism tasks consume it, but a late seam fix may be needed if the
+suite surfaces one — the task owns absorbing it.
+
+## References
+
+- docs/architecture/decisions/024-mem-engine.md §5 (acceptance items);
+  022-contract-suite-layout.md (the factory both engines already
+  implement — the shape to mirror)
+- docs/architecture/engine-mem.md (spec of record)
+- tasks/sqlite-engine-integration.md / tasks/pg-engine-integration.md
+  (the structural twins' integration tasks of record)
+- tasks/review-wave-5.md appendix (the discharge map the third column
+  rides)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/mem-engine-locks.md b/tasks/mem-engine-locks.md
new file mode 100644
index 0000000..c125234
--- /dev/null
+++ b/tasks/mem-engine-locks.md
@@ -0,0 +1,65 @@
+---
+id: mem-engine-locks
+name: Mem engine — named locks (in-memory TTL registry)
+status: pending
+depends_on: [mem-engine-seam-tx]
+scope: narrow
+risk: low
+impact: component
+level: implementation
+tags: [wave-6, mem-engine, locks]
+---
+
+## Description
+
+The named-locks mechanism over an in-memory TTL registry
+(engine-mem.md §Mapping the contract, locks row):
+
+- `store.try_lock(name, owner, ttl)` — acquire or fail (`Option<Lock>
+  `; no-work is a value); validation at entry (empty → `InvalidName`,
+  reserved → `ReservedName`); **duration guard at entry** —
+  `ttl <= 0` rejects with opaque `Err`
+  ([ADR-023](../architecture/decisions/023-fourth-review-round.md) §2,
+  durations kind), never a silent immediately-expired lease.
+- **`Lock` handle** ([ADR-019](../architecture/decisions/019-mechanism-handle-surfaces.md)):
+  `renew(ttl)` (absolute reset; renews past expiry refused) and
+  `release`. Registry entries carry owner + deadline; expiry is a
+  clock check at try/renew boundaries (tokio time; no ambient
+  revoker) — after TTL expiry exclusion lapses *silently* (the
+  ADR-008 §7 row), re-acquirable; the holder may still release.
+- **Single-instance contention semantics**: two `try_lock`s on the
+  same name within the registry are serialized by the guarded-state
+  discipline — first wins, second gets `None` cleanly (the SQLite
+  busy-path question has no mem analog; loser is a value, never an
+  error). Not part of the tx seam (no `lock_tx` — contract-verbatim:
+  a lock held across a business tx is held by explicit acquisition;
+  the overlay neither sees nor stages locks).
+
+## Acceptance Criteria
+
+- [ ] `try_lock`/`renew`/`release` over the TTL registry; entry
+      validation (names + duration guard) — pinned
+- [ ] TTL expiry: silent lapse, re-acquisition, renew-past-expiry
+      refused — pinned (clock-controlled tests via the state core's
+      clock accessor)
+- [ ] Concurrent-contention shape: loser is `None`, winner's lease
+      intact — pinned
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean; workspace gates green
+
+## References
+
+- docs/architecture/core-contract.md §named locks
+- docs/architecture/decisions/008-contract-v1-pinning.md §7;
+  019-mechanism-handle-surfaces.md; 023 §2
+- docs/architecture/engine-mem.md §Mapping the contract (locks row)
+- tasks/pg-engine-locks.md (the structural twin's task of record —
+  the duration guards land identically)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/mem-engine-notify-listen.md b/tasks/mem-engine-notify-listen.md
new file mode 100644
index 0000000..b5ee833
--- /dev/null
+++ b/tasks/mem-engine-notify-listen.md
@@ -0,0 +1,73 @@
+---
+id: mem-engine-notify-listen
+name: Mem engine — notify/listen surface (`WakeReceiver`, close-at-engine-drop)
+status: pending
+depends_on: [mem-engine-seam-tx]
+scope: narrow
+risk: medium
+impact: component
+level: implementation
+tags: [wave-6, mem-engine, notify]
+---
+
+## Description
+
+The notify/listen mechanism over the state core's wake-routing
+substrate (engine-mem.md §Architecture):
+
+- `store.notify(channel, payload)` — validation like every engine
+  (empty → `InvalidName`, reserved → `ReservedName`); encode via
+  core's `encode_payload` (`Codec` on failure, ADR-023 §1); delivers
+  committed-notify wakes to each open receiver on that channel at the
+  commit boundary, per-subscriber FIFO by commit order, never
+  coalesced (no batching boundary exists). No size limit at any size —
+  `PayloadTooLarge` is never produced (engine asymmetry classification,
+  [ADR-024](../architecture/decisions/024-mem-engine.md) §3).
+- `store.listen(channel) -> Box<dyn WakeReceiver>` — starts from
+  "now" (attaches at the current commit watermark; a listener attached
+  after a commit never sees it). Delivers opaque
+  `Wake { channel }` signals — `recv`/`try_recv`/`recv_timeout` forms
+  per the pinned shapes ([ADR-008](../architecture/decisions/008-contract-v1-pinning.md)
+  §3).
+- `notify_tx` — staged in the tx overlay by `mem-engine-seam-tx`; this
+  task's contract obligation is the close arms: **one close path —
+  engine drop closes open receivers** (process exit/shutdown;
+  terminal `recv() -> None`, cause = the documented engine asymmetry
+  realized as drop). No reconnection concept exists; the
+  reconnect-wake channel is never emitted (the reserved string stays
+  reserved but unused — and still rejected as a consumer name).
+
+Unit tests pin: channel-scoped delivery + foreign-channel silence
+(with the field carried, per the suite row's scoping observable),
+burst floor (≥1 wake), attach-after-commit no-replay, close-at-drop
+terminal `None`, commit-boundary delivery timing through
+`notify_tx` (nothing pre-merge).
+
+## Acceptance Criteria
+
+- [ ] listen/notify surface trait-complete with entry validation and
+      core payload encoding
+- [ ] Wake delivery: commit-ordered, channel-scoped, no-replay,
+      never coalesced — unit-pinned
+- [ ] Engine drop closes open receivers (terminal `None`) — pinned
+- [ ] `notify_tx` delivers wakes only after the overlay merge —
+      pinned with the seam task's commit-atomicity tests
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean; workspace gates green
+
+## References
+
+- docs/architecture/core-contract.md §notify / listen
+- docs/architecture/decisions/006-wake-and-delivery-contract.md;
+  008-contract-v1-pinning.md §3; 021-tx-reads-and-value-shape-fixes.md §5
+- docs/architecture/engine-mem.md §Architecture, §Asymmetry classification
+- tasks/suite-wake-rows.md (the suite row the mem column will run —
+  the observable shapes it pins)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/mem-engine-queues.md b/tasks/mem-engine-queues.md
new file mode 100644
index 0000000..3ad9063
--- /dev/null
+++ b/tasks/mem-engine-queues.md
@@ -0,0 +1,86 @@
+---
+id: mem-engine-queues
+name: Mem engine — queues (in-memory job table, ADR-010 state machine, engine-owned backoff curve)
+status: pending
+depends_on: [mem-engine-seam-tx, mem-engine-notify-listen]
+scope: moderate
+risk: medium
+impact: component
+level: implementation
+tags: [wave-6, mem-engine, queues]
+---
+
+## Description
+
+The queue mechanism: the
+[ADR-010](../architecture/decisions/010-queue-semantics-depth.md) state
+machine realized over an in-memory job table — all driver-free.
+
+- **`Queue` handle surface** ([ADR-019](../architecture/decisions/019-mechanism-handle-surfaces.md)
+  §1): `enqueue` (auto-commit, resolving over the handle's opts),
+  `claim_one`/`claim_batch` (extents: `n <= 0` claims nothing),
+  `ack_batch` (per-id uniform predicate, lapsed/non-claimed silently
+  not counted), `cancel` (unconditional delete), `get_job`, and the
+  queue-scoped `sweep_expired` (no-stranded-rows: *every* past-expiry
+  row in any state moves to dead + retention enforcement).
+- **Claim discipline**: exactly-once handout, `worker_id` claimant
+  identity (non-empty), claim ordering priority DESC → ready-time →
+  enqueue FIFO. Visibility expiry and reclaim — **reclaim consumes an
+  attempt**; the dual-execution window is contract-honest (a worker
+  past its deadline may complete its work but its ack will not land).
+  Under a single engine instance the claim race is in-process — the
+  guarded merge discipline must still make claim-vs-claim atomic and
+  claim-vs-expiry deterministic at the row level.
+- **JobHandle ops** ([ADR-019](../architecture/decisions/019-mechanism-handle-surfaces.md)
+  §3): `ack`/`retry`/`fail` one-shot terminal, `heartbeat(&self)`
+  repeatable absolute-reset renewal; the uniform validity predicate
+  (processing + unexpired deadline); deadline lapse refuses all ops,
+  false not error. `retry(err, None)` computes the queue's
+  **equal-jitter exponential delay — mem's own implementation**
+  ([ADR-012](../architecture/decisions/012-forked-substrate-design.md)
+  §2's one-owner rule, third owner; the SQLite engine's `resolution.rs`
+  is reference, not a dependency); `retry(err, Some(d))` overrides
+  verbatim; `fail` = immediate dead-letter with the engine-default
+  strings (`"failed"` / `"max attempts exceeded"`).
+- **Opts stamping** ([ADR-020](../architecture/decisions/020-enqueue-opt-semantics-and-bridges.md)):
+  resolution rules (delay-over-`run_at`, relative `expires`) are
+  mem-owned (third copy); handle-enqueue stamps the handle's opts;
+  the tx/no-handle shapes stamped plain 300/3/5/none in
+  `mem-engine-seam-tx`. `get_job` shows resolved values.
+- **Dead letters**: move-to-dead storage, `get_job` sees dead rows
+  (`last_error`/`died_at`), `dead_letter_retention_s` (None = forever)
+  enforced by `sweep_expired`. No redrive API.
+- Timestamps and expiry checks are tokio-time/clock reads against the
+  state core's clock accessor; expiry is *checked* at claim/renew
+  boundaries (no ambient sweeper — `sweep_expired` is caller-driven,
+  cadence recipe unchanged).
+
+## Acceptance Criteria
+
+- [ ] Full `Queue`/`JobHandle` surfaces over the in-memory job table
+- [ ] The ADR-010 state machine properties unit-pinned: visibility
+      reclaim consumes an attempt, dead-letter moves, no-stranded-rows
+      sweep, handle-op validity predicate, late-heartbeat boundary
+- [ ] Equal-jitter curve + opts resolution pinned to the identical
+      numeric behavior the suite's equivalence rows assert (per the
+      engine-side pin posture used for the cap legs)
+- [ ] Numeric-domain guards (extents) at entry — pinned
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean; workspace gates green
+
+## References
+
+- docs/architecture/queues.md; core-contract.md §queues
+- docs/architecture/decisions/010-queue-semantics-depth.md;
+  019-mechanism-handle-surfaces.md §1/§3; 020 §1–§3; 023 §2
+- docs/architecture/engine-mem.md §Mapping the contract (queues row)
+- tasks/pg-engine-queues.md (the structural twin's task of record —
+  the wave-4 rhythm and the resolution rule set)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/mem-engine-scheduler-outbox.md b/tasks/mem-engine-scheduler-outbox.md
new file mode 100644
index 0000000..f6d696e
--- /dev/null
+++ b/tasks/mem-engine-scheduler-outbox.md
@@ -0,0 +1,87 @@
+---
+id: mem-engine-scheduler-outbox
+name: Mem engine — scheduler (`schedule`/`unschedule`/`run_schedules`) and outbox helper
+status: pending
+depends_on: [mem-engine-queues, mem-engine-locks]
+scope: moderate
+risk: medium
+impact: component
+level: implementation
+tags: [wave-6, mem-engine, scheduler, outbox]
+---
+
+## Description
+
+The collapsed scheduler and the outbox helper
+([ADR-009](../architecture/decisions/009-scheduler-collapse.md),
+[ADR-014](../architecture/decisions/014-outbox-tx-enqueue.md)):
+
+- **Scheduler surface**: `schedule(name, spec, queue, payload, opts)`
+  (upsert by name; *both* name-bearing arguments validated — schedule
+  name and queue argument identically, `InvalidName`/`ReservedName`),
+  `unschedule(name) -> bool`, and the opt-in
+  `run_schedules(stop: StopToken)` runner over a mem-owned tick task.
+- **Tick machinery — engine-uniform** ([ADR-009](../architecture/decisions/009-scheduler-collapse.md)
+  §4's rule; single-instance leadership is trivially owned but the
+  machinery still runs): each boundary fire enqueues ordinary work
+  stamped with the schedule's `ScheduleOpts` resolved over the target
+  queue's derived engine defaults; fire+advance is atomic under the
+  guarded state (the no-double-fire floor); **bounded catch-up with
+  the fixed 64-boundary cap and skip-forward past the cap**
+  (mem-owned tick implementation — third owner per
+  [ADR-012](../architecture/decisions/012-forked-substrate-design.md)
+  §2); leadership rides the reserved `__alkstore_scheduler` lock
+  through the lock mechanism (so two runners on one instance contend
+  through the same machinery the other engines use; loss →
+  `Err(LeadershipLost)`, clean stop → `Ok(())`).
+- **Spec grammar v1**: `@every <n><unit>` (`s|m|h|d`) only — mem owns
+  its parser (third copy, the grammar is small and pinned); cron
+  strings rejected (`InvalidSpec`). Boundary waits ride tokio time.
+- **Outbox helper**: `Outbox { enqueue, run_once }` per
+  [ADR-019](../architecture/decisions/019-mechanism-handle-surfaces.md)
+  §5 — `run_once(worker_id, delivery) -> bool` is pull: claim one,
+  ack on `Ok`, `retry(err, None)` on `Err`; **no engine-issued
+  heartbeat inside delivery** (inherited posture);
+  `outbox_enqueue_tx` staged in the overlay by `mem-engine-seam-tx`
+  (the 60/5/5 stamp set); the derived backing queue
+  `__alkstore_outbox:{outbox}` unreachable by `enqueue_tx`
+  (validation already pins the reserved prefix), name format pinned
+  identical to the other engines (the suite's derived-queue-naming
+  row composes it).
+
+Unit tests pin: boundary fires (deterministic, tokio-time driven),
+bounded catch-up + skip-forward, leadership lock contention/loss
+through two `run_schedules` calls, outbox run_once ack/retry shapes,
+derived-name format.
+
+## Acceptance Criteria
+
+- [ ] Scheduler surface + tick: boundary fire, catch-up (≤64),
+      skip-forward — unit-pinned with tokio-time determinism
+- [ ] Leadership contention through the `__alkstore_scheduler` lock;
+      `LeadershipLost` on loss, `Ok(())` on clean stop — pinned
+- [ ] Schedule name + queue argument validation; `@every`-only parser
+      (cron → `InvalidSpec`) — pinned
+- [ ] Outbox: `enqueue`/`run_once` semantics (no engine heartbeat);
+      derived backing-queue name format identical to both engines —
+      pinned
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean; workspace gates green
+
+## References
+
+- docs/architecture/queues.md; core-contract.md §scheduler, §outbox
+- docs/architecture/decisions/009-scheduler-collapse.md §1/§3/§4/§6;
+  014-outbox-tx-enqueue.md; 019 §4/§5; 020 §3
+- docs/architecture/engine-mem.md §Mapping the contract
+  (scheduler/outbox row)
+- tasks/pg-engine-scheduler-outbox.md (the structural twin's task of
+  record — tick/catch-up/leadership shapes)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/mem-engine-seam-tx.md b/tasks/mem-engine-seam-tx.md
new file mode 100644
index 0000000..06b63b2
--- /dev/null
+++ b/tasks/mem-engine-seam-tx.md
@@ -0,0 +1,95 @@
+---
+id: mem-engine-seam-tx
+name: Mem engine — tx overlay, `Store` surface, `TxHandle` (staged `*_tx`, commit-merge + wake-at-commit, drop = discard)
+status: pending
+depends_on: [mem-engine-foundations]
+scope: moderate
+risk: high
+impact: component
+level: implementation
+tags: [wave-6, mem-engine, seam]
+---
+
+## Description
+
+The seam task, and the wave's load-bearing artifact
+(engine-mem.md §The tx overlay): the `Store` trait impl plus the tx
+overlay's full discipline.
+
+- **`Store` surface**: the trait methods (`notify`, `stream`,
+  `queue`, `outbox`, `try_lock`, `listen`, `schedule`, `unschedule`,
+  `run_schedules`, `begin_tx`, `with_tx`) implemented over the
+  state core. `queue(name, opts)`/`outbox(name)` create/return
+  handles whose opts ride the handle (queues are names, not config
+  owners — the §3a stamp rules apply identically). Mechanism handles
+  are core-owned trait objects; engine types never appear in
+  signatures.
+- **The tx overlay**: `begin_tx()` allocates a handle-private overlay.
+  All eleven `*_tx` methods stage effects in it — `enqueue_tx`,
+  `publish_tx`, `publish_with_key_tx`, `notify_tx`,
+  `save_offset_tx`, `get_job_tx`, `get_offset_tx`, `read_since_tx`,
+  `read_from_consumer_tx`, `outbox_enqueue_tx`, `commit`. Reads *inside* the tx merge the overlay over committed state (read-
+  your-own-writes, no round-trips: the tx-read rows'
+  `get_job_tx`/`read_since_tx` behaviors come free, but pin them).
+  Opt-stamping of staged effects runs at *enqueue* time on the
+  overlay (resolution identical to the no-handle paths, per
+  [ADR-020](../architecture/decisions/020-enqueue-opt-semantics-and-bridges.md)
+  §3: `enqueue_tx` stamps plain derived defaults 300/3/5/none;
+  `outbox_enqueue_tx` the 60/5/5 set).
+- **Commit-merge + wake-at-commit**: commit merges the overlay
+  atomically (single guarded merge) and fires the overlay's pending
+  wakes *in the same operation* — a tx-staged notify delivers nothing
+  until the merge (the discipline pg got wrong and fixed via
+  `pg-fix-tx-wake`; here structural, and pinned from birth by the
+  suite's tx-commit-atomicity rows once integration wires them).
+- **Drop = discard**: dropping the handle without commit/rollback
+  discards the overlay (rollback explicit form too) — no-ghosts
+  trivially, uncommitted state never touched committed state.
+  `with_tx` composition: `Ok` ⇒ commit, `Err`/drop/panic ⇒ rollback
+  (the N-5 panic posture applies; overlay discard must be panic-safe
+  through the unwind's drop).
+- **Numeric domains** ([ADR-023](../architecture/decisions/023-fourth-review-round.md)
+  §2): validation at the trait-impl entry, before any storage-layer
+  effect — extents clamp empty, durations reject, boundaries total.
+  Same entry-point rule as the other engines, realized engine-side.
+
+Engine-internal unit tests pin the overlay discipline directly
+(merge atomicity, wake-after-not-before, drop-discard, panic-through-
+unwind) in the family's mechanism-test posture; the suite column's
+cross-engine rows land in `mem-engine-integration`.
+
+## Acceptance Criteria
+
+- [ ] The full `Store`/`TxHandle` trait surfaces implemented over
+      guarded state; no engine types in consumer signatures
+- [ ] Overlay staging → commit-merge → wake-at-commit pinned by unit
+      tests (a tx-staged notify delivers nothing pre-commit, one wake
+      post-commit; enqueue/publish commit-atomicity shapes)
+- [ ] Drop-without-commit and explicit rollback leave zero residue;
+      `with_tx` panic rolls back through the unwind's drop
+- [ ] Tx reads see staged effects; other views see none pre-commit;
+      post-rollback reads' subjects gone (no-ghosts for reads)
+- [ ] Numeric-domain guards at entry (extents/durations/boundaries)
+      pinned per [ADR-023](../architecture/decisions/023-fourth-review-round.md) §2
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean; workspace gates green
+
+## References
+
+- docs/architecture/core-contract.md §The seam; §Cross-cutting contracts
+- docs/architecture/decisions/007-transactional-seam.md;
+  014-outbox-tx-enqueue.md; 020-enqueue-opt-semantics-and-bridges.md
+  §3; 021-tx-reads-and-value-shape-fixes.md; 023-fourth-review-round.md §2
+- docs/architecture/engine-mem.md §The tx overlay (the spec of record)
+- tasks/pg-fix-tx-wake.md (the failure shape the overlay makes
+  structurally impossible)
+- tasks/review-wave-5.md appendix (the suite rows whose mem wiring
+  consumes this task)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/mem-engine-streams.md b/tasks/mem-engine-streams.md
new file mode 100644
index 0000000..0022023
--- /dev/null
+++ b/tasks/mem-engine-streams.md
@@ -0,0 +1,80 @@
+---
+id: mem-engine-streams
+name: Mem engine — streams (in-memory log, per-consumer offsets, trim)
+status: pending
+depends_on: [mem-engine-seam-tx, mem-engine-notify-listen]
+scope: moderate
+risk: medium
+impact: component
+level: implementation
+tags: [wave-6, mem-engine, streams]
+---
+
+## Description
+
+The streams mechanism over an in-memory event log + per-consumer
+offset table (engine-mem.md §Mapping the contract, streams row):
+
+- **`StreamHandle` surface** ([ADR-019](../architecture/decisions/019-mechanism-handle-surfaces.md)
+  §2): `publish` / `publish_with_key` (present key must be non-empty
+  → `InvalidName`), `read_since` / `read_from_consumer` (cursor reads,
+  `offset ASC`, extents clamp empty per
+  [ADR-023](../architecture/decisions/023-fourth-review-round.md) §2),
+  `save_offset` / `get_offset` (monotone saves — below-checkpoint
+  saves are silent no-ops, `Err` arm carries `Database` only),
+  `trim_to` (delete `offset <= horizon`, exact-boundary, returns
+  deleted count, negative horizon deletes nothing idempotently,
+  **wakes nothing**, surviving rows keep offsets, never renumbered),
+  and `subscribe` (durable consumption: attach, read to tail, resume
+  from saved offset; wake-driven with re-read — the wake substrate
+  delivers at commit; explicit saves only, no auto-checkpoint).
+- **Ordering**: engine-assigned monotonically increasing per-stream
+  offsets, global FIFO by offset — the ADR-015 ordering row, mem's own
+  counter (per-stream; absolute values need not equal the SQL engines'
+  — the equivalence rows pin relative order).
+- **`StreamEvent` shape** exactly as pinned
+  ([ADR-015](../architecture/decisions/015-streams-depth.md) §3):
+  `{ offset, stream, key, payload, created_at }` — `created_at` is
+  unix-seconds at publish, informational, from the clock accessor.
+  Reads from a trimmed-away region resume at the horizon's first
+  remaining row.
+- **Keyed publish rides the tx overlay** (staged `publish_with_key_tx`
+  landed in `mem-engine-seam-tx`); this task's non-tx forms, receiver,
+  and trim live here.
+- **Receiver close arms** ([ADR-021](../architecture/decisions/021-tx-reads-and-value-shape-fixes.md)
+  §5): `recv()`'s `Err` carries `Database` only (payloads cross raw;
+  `Codec` at `payload_as<T>`); close is terminal — the one close path
+  is engine drop (the notify-listen task's close arm, realized
+  identically); no reconnection concept (the pg stays-open-across-
+  reconnect row is absent from mem's column).
+
+## Acceptance Criteria
+
+- [ ] Full `StreamHandle` surface over the in-memory log +
+      per-consumer offsets
+- [ ] The ADR-015 properties unit-pinned: global FIFO, immutable
+      never-renumbered offsets (gaps legal post-trim), exact-boundary
+      trim semantics (reads resume at horizon; saved sub-horizon
+      offsets stay valid; trim wakes nothing), monotone save
+      composition (direct + receiver forms interleave)
+- [ ] Key round-trips exactly (`None` vs `Some`); empty-`Some`-key
+      rejected at every entry point
+- [ ] Extent/offset numeric-domain guards at entry — pinned
+- [ ] `cargo check --target wasm32-unknown-unknown -p alkstore-mem`
+      clean; workspace gates green
+
+## References
+
+- docs/architecture/core-contract.md §streams
+- docs/architecture/decisions/015-streams-depth.md;
+  019-mechanism-handle-surfaces.md §2/§6; 021 §5; 023 §2
+- docs/architecture/engine-mem.md §Mapping the contract (streams row)
+- tasks/pg-engine-streams.md (the structural twin's task of record)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/pg-fix-open-path.md b/tasks/pg-fix-open-path.md
index 272c8e0..0795c23 100644
--- a/tasks/pg-fix-open-path.md
+++ b/tasks/pg-fix-open-path.md
@@ -1,6 +1,6 @@
 ---
 id: pg-fix-open-path
-name: Fix `max_size: 0` open hang + DSN options override (review 002 Finding 3 + options note)
+name: "Fix `max_size: 0` open hang + DSN options override (review 002 Finding 3 + options note)"
 status: completed
 depends_on: []
 scope: single
diff --git a/tasks/pg-fix-scheduler-tick-seam.md b/tasks/pg-fix-scheduler-tick-seam.md
new file mode 100644
index 0000000..b35f9bf
--- /dev/null
+++ b/tasks/pg-fix-scheduler-tick-seam.md
@@ -0,0 +1,68 @@
+---
+id: pg-fix-scheduler-tick-seam
+name: "pg scheduler — transient-fault tick seam: retry/exhaustion arms tested (review 003 Finding 1)"
+status: pending
+depends_on: []
+scope: narrow
+risk: low
+impact: component
+level: implementation
+tags: [wave-6, postgres-engine, scheduler, test-hardening]
+---
+
+## Description
+
+Review 003 Finding 1 (MEDIUM — `docs/reviews/003-wave-5-general-review.md`):
+the pg scheduler's transient-error retry loop
+(`alkstore-postgres/src/scheduler.rs:680-704`, `tick_with_retries`)
+has never executed under any test — `pg-fix-scheduler-resilience`
+pinned its *constants* (`the_tick_retry_policy_is_pinned`) but the
+loop that uses them (retry, backoff sleeps, exhaustion error, the
+`eprintln` diagnostic — lcov 171-184, 237-260) is dead code under
+test, with no fault seam anywhere in the pg scheduler for `tick_once`.
+This is the last uncovered hardening arm from the wave-4 fix batch,
+and the exact class that produced review 002's live bugs.
+
+Fix shape (the review's recommendation): a `cfg(test)` transient-
+fault seam on the pg tick path, following the `sqlite-commit-error-arm
+` precedent — a one-shot armed flag feeding a fabricated
+transient error into the *real* retry loop (never a replica):
+
+- (a) one retried tick then success: the seam faults once, the next
+  `tick_once` succeeds, the job processes — the retry + backoff-sleep
+  arms execute for real;
+- (b) exhaustion: the seam faults the max retry count, the loop
+  exhausts to the typed error shape and the `eprintln` diagnostic
+  fires, the runner survives (the resilience property the fix
+  promised).
+
+Cross-test safety is per-store scoping (the commit-fault seam's
+pattern); no production-path changes — the seam is cfg-gated, born
+disarmed, consumed-on-use.
+
+## Acceptance Criteria
+
+- [ ] The seam lands cfg(test)-gated; the real `tick_with_retries`
+      executes under test (no loop replication)
+- [ ] Arms (a) and (b) pinned as above; the runner survives
+      exhaustion
+- [ ] `cargo test -p alkstore-postgres` green against the harness
+      server; skips clean server-less
+- [ ] Clippy `-D warnings`, fmt clean; workspace gates green
+
+## References
+
+- docs/reviews/003-wave-5-general-review.md §Finding 1 (sites, lcov
+  inventory, recommendation)
+- docs/architecture/decisions/024-mem-engine.md (the wave-6 window
+  this rider rides — the plan's wave-6 section, "Riding the window")
+- tasks/sqlite-commit-error-arm.md (the seam pattern of record)
+- tasks/pg-fix-scheduler-resilience.md (the constants the loop uses)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/review-wave-6.md b/tasks/review-wave-6.md
new file mode 100644
index 0000000..9e43e67
--- /dev/null
+++ b/tasks/review-wave-6.md
@@ -0,0 +1,81 @@
+---
+id: review-wave-6
+name: Review gate — wave 6 (mem engine)
+status: pending
+depends_on: [mem-engine-integration, pg-fix-scheduler-tick-seam]
+scope: moderate
+risk: low
+impact: phase
+level: review
+tags: [wave-6, review]
+---
+
+## Description
+
+The wave-6 review gate (the plan's §Review gates, wave 6; the
+born-pinned gate). Code-read the `alkstore-mem` engine against the
+contract and the pinned ADR-024 text, and audit:
+
+1. **Conformance read**: engine-vs-contract line by line, mirroring
+   the wave-3/4 gate pattern — every trait surface against
+   core-contract.md and the pinning ADRs (007/008/009/010/015/019/
+   020/021/023), the tx overlay against ADR-024 + engine-mem.md §The
+   tx overlay (commit-merge atomicity, wake-at-commit, drop = discard,
+   panic-through-unwind).
+2. **The third column as the compatibility instrument born pinned**:
+   the mem column's wiring read row-by-row against the discharge map
+   (which rows carry, which engine-shaped rows omit and why — the
+   asymmetry classification, ADR-024 §3); `PayloadTooLarge`
+   non-occurrence arm present; three-way arithmetic equivalence
+   actually asserted green (backoff curve, opts resolution — the
+   ADR-012 §2 one-owner rule's third owner), plus the derived-queue
+   naming row composing identically.
+3. **wasm32 acceptance audit** (ADR-024 §5): the compile gate clean,
+   tokio feature subset verified on the manifest, no blocking calls
+   in mem internals, the current-thread flavor actually enforced by
+   the column's tests.
+4. **engine-mem.md read against the implemented engine**; the
+   deployment matrix's mem rows (`deployment.md`, landed with ADR-024)
+   still true as implemented (honesty carriers: identity + docs +
+   matrix — nothing runtime invented). Gate may flip `engine-mem.md`
+   to `stable` if the read is clean.
+5. **The rider closed**: `pg-fix-scheduler-tick-seam`'s arms verified
+   (review 003 Finding 1 discharged into this window; Findings 2–3
+   confirmed still parked for wave 7).
+6. **Contract-window discipline**: the class-1 amend-in-place window
+   is still open — any wobble the third implementation surfaced must
+   appear as resolved ADR text (or be recorded as a finding with its
+   disposition), not as a silent divergence between suite row and
+   engine behavior.
+
+## Acceptance Criteria
+
+- [ ] Full conformance code-read recorded (findings + dispositions
+      inline in this task's Notes, mirroring review-wave-3/4 style)
+- [ ] Suite mem column green on host, 25-row set wired per the
+      classification; three-way equivalence rows green
+- [ ] wasm32 compile gate + feature-subset + current-thread flavor
+      verified, recorded
+- [ ] The rider's arms verified; Finding 1 disposition recorded
+- [ ] Workspace gates re-run green this session (`cargo build`,
+      `cargo test`, clippy `-D warnings`, fmt)
+- [ ] `engine-mem.md` disposition decided (stable flip or follow-up)
+      and `implementation.md`'s wave-6 row updated
+
+## References
+
+- docs/plans/implementation.md §Wave 6, §Review gates (wave 6 entry)
+- docs/architecture/decisions/024-mem-engine.md (the charter this
+  gate audits code against)
+- docs/architecture/engine-mem.md
+- tasks/review-wave-3.md / tasks/review-wave-4.md (the gate pattern)
+- docs/reviews/003-wave-5-general-review.md (Finding 1's disposition
+  trail; Findings 2–3's wave-7 park)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file
diff --git a/tasks/suite-harness-current-thread.md b/tasks/suite-harness-current-thread.md
new file mode 100644
index 0000000..33c606e
--- /dev/null
+++ b/tasks/suite-harness-current-thread.md
@@ -0,0 +1,62 @@
+---
+id: suite-harness-current-thread
+name: Contract-suite harness — async sleep in `past_stamp_sleep`, current-thread flavor readiness
+status: pending
+depends_on: []
+scope: narrow
+risk: low
+impact: component
+level: implementation
+tags: [wave-6, contract-suite]
+---
+
+## Description
+
+The one suite-side change wave 6 carries
+([ADR-024](../architecture/decisions/024-mem-engine.md) §5 item 4; the
+review-003 posture note at `properties.rs:1683`): the suite's
+`past_stamp_sleep` helper uses a blocking `std::thread::sleep` inside
+async rows — safe under the multi-thread test flavors both existing
+engines' targets use, but it would stall a current-thread runtime. The
+mem engine's suite column **must** run under a current-thread flavor
+(`#[tokio::test(flavor = "current_thread")]`) to keep the mem
+engine's internals honestly current-thread-clean — which is what
+wasm32 needs.
+
+- Replace `past_stamp_sleep`'s blocking sleep with `tokio::time::sleep`
+  (async). The helper's semantics are unchanged (a bounded
+  pre-`run_at` settle before reads); the existing rows' determinism
+  posture is untouched — verify the two legs using it re-run green on
+  both engines with no timing drift (tolerances unchanged).
+- Document (one line in the helper's doc comment or the factory
+  contract notes) the harness posture: **no blocking calls inside
+  suite rows** — the mem column enforces the flavor that catches
+  violations.
+
+This task is engine-independent and can run any time before
+`mem-engine-integration` wires the third column.
+
+## Acceptance Criteria
+
+- [ ] `past_stamp_sleep` is async (`tokio::time::sleep`)
+- [ ] Both engines' existing suites re-run green with identical
+      assertions and tolerances (determinism posture intact)
+- [ ] The no-blocking-calls posture noted where the harness's
+      determinism posture is documented
+- [ ] Clippy `-D warnings`, fmt clean; workspace gates green
+
+## References
+
+- docs/architecture/decisions/024-mem-engine.md §5
+- docs/reviews/003-wave-5-general-review.md §Finding 5 (the
+  `properties.rs:1683` posture note)
+- docs/architecture/decisions/022-contract-suite-layout.md (the
+  factory contract the flavor rides)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion
\ No newline at end of file