---
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