# T16 closure roadmap — full coverage with correct behaviours

**Goal state.** Every spec'd cross-stack scenario green in suite-mode
sweeps, asserting its full design intent (no soft-passes, no vacuous
threshold loosening), with CI gating live and stable.

**Where we are.** The merged `claude/cross-stack-interop-test-XAbYB`
branch ships 22 of 23 spec'd scenarios; each passes individually.
Suite-mode runs hit a residual moq-relay 0.10.x routing race on a
specific subset (~40-60% flake rate). Five scenarios soft-pass the
listener side as a known-flake mitigation. CI is intentionally
unwired pending stability.

This roadmap takes the suite from "passes individually" to "passes
in suite + CI" through three sequential plans. None should be
parallelized — each unblocks the next.

## Priority 1 — `2026-05-07-moq-relay-routing-investigation.md`

**Why first.** The race is the root cause of every soft-pass and
the reason CI isn't wired. Without resolving it, downstream plans
mask flake rather than catch regressions.

**What lands.**
- Either an upstream moq-relay version bump that closes the bug,
  OR a documented relay configuration tweak that does.
- Or, if neither: a filed `kixelated/moq` issue with reproducer +
  trace pair, plus a documented decision to keep CI unwired until
  upstream resolves.

**Acceptance bar.** 5/5 sweep BUILD SUCCESSFUL on the existing
HangInteropTest + BrowserInteropTest with their CURRENT soft-pass
assertions intact. (The next step tightens those.)

## Priority 2 — `2026-05-07-tighten-cross-stack-assertions.md`

**Why second.** Once the suite is stable, every soft-pass that
returned vacuous-pass on listener-side 0-frame outcomes is now
HIDING regressions instead of side-stepping flakes. Replace each
with a hard floor.

**What lands.**
- Five BrowserInteropTest scenarios get hard sample-count + FFT
  floors (or tightened existing ones).
- Gap matrix updated to reflect hard-pass coverage.

**Acceptance bar.** 5/5 sweep AGAIN, this time with hard
assertions. If anything fail-flakes, the routing investigation
isn't really done — loop back.

## Priority 3 — `2026-05-07-cross-stack-interop-ci-gating.md`

**Why third.** Stability + hard-asserts in place → CI is now a
net positive (catches regressions, doesn't burn maintainer time
on false reds).

**What lands.**
- Re-add `hang-interop` job (was at commit `6829ab727`'s parent;
  `git show 6829ab727 -- .github/workflows/build.yml` reverse
  gives the exact diff).
- Re-add `browser-interop` job (same pattern, plus bun +
  Playwright caches).
- Documentation update across the results plan + gap matrix.

**Acceptance bar.** 10/10 sweep before merge; ≥ 95% CI green
rate over the first 2 weeks. If lower, the upstream race isn't
fully closed — pull the jobs.

## Independent track — `2026-05-07-framespergroup-production-rerun.md`

This one **doesn't block the closure roadmap**. It can run any
time after Priority 1 is done; it settles whether the test pin
(5) and production default (50) can converge, or whether they
must remain different. Either outcome is shippable.

**What lands.**
- Logcat data from a fresh two-phone field test against current
  nostrnests production at multiple `framesPerGroup` values.
- A data-driven decision on whether to change the production
  default, the test pin, or neither.

**Why it's parallelizable.** Doesn't gate the test suite or CI;
it gates a one-line code change to `NestMoqLiteBroadcaster`'s
default constant.

## After all four close — what remains

Two open items, both genuinely upstream:

1. **I7 post-reconnect listener cliff** —
   `2026-05-07-i7-post-reconnect-cliff-investigation.md`. The I7
   reverse scenario passes its 2.5 s threshold but a regression
   test of "all post-reconnect data arrives" would require the
   moq-relay 0.10.x per-broadcast forward queue fix. Same upstream
   class as the routing race.

2. **I12 GOAWAY** — only re-emerges if an IETF moq-transport
   target lands (currently moq-lite-03 only). Tracked in
   `2026-05-06-cross-stack-interop-test-results.md`.

Beyond those: T16 reaches "full coverage with correct behaviours"
when this roadmap closes.

## Estimated wallclock

- Priority 1: 1–2 days (depends on whether upstream version bump
  fixes it, or we have to file + wait for upstream).
- Priority 2: 0.5 day (mechanical replacement of soft-passes
  with floors, plus rerun verification).
- Priority 3: 0.5 day (re-add CI jobs, run the 10× sweep, merge).
- Independent track (framesPerGroup): 0.5 day (needs prod-rig
  access).

Total: 2.5–3.5 days of focused work to take T16 from "infra
shipped" to "fully closed".

## Plan files

- `2026-05-07-moq-relay-routing-investigation.md`
- `2026-05-07-tighten-cross-stack-assertions.md`
- `2026-05-07-cross-stack-interop-ci-gating.md`
- `2026-05-07-framespergroup-production-rerun.md`
- (this file) `2026-05-07-t16-closure-roadmap.md`