# XZBT-NGN Step 6.7 — Closure Report

**Status: accepted.** As of 2026-09-15, Step 6.7 is closed and
`f163de264388f1e411cf9e54f26f72a254888afd` is frozen as the accepted Contract
5.3 baseline by the annotated tag `contract-5.3-accepted-baseline`. The full
automated suite, the SciFi surface smoke suite, packaged standalone verification,
and the live eight-point NGN verification have all passed. *(Note: Step 6.8 was
subsequently completed and accepted, and Step 6 is closed at Step 6.10; see the
[Step 6.10 closure report](XZBT-NGN-Step6.10-Closure-Report.md).)*

- Step 6.7A (design, no code): [architecture report](../architecture/XZBT-NGN-Step6.7A-SciFi-Observation-Surface.md)
- Step 6.7B (implementation): [implementation report](XZBT-NGN-Step6.7-SciFi-Surface-Adaptation.md)
- Packaging evidence: [step6.7-packaging.txt](../../test-fixtures/evidence/step6.7-packaging.txt)
- Fixture provenance: [PROVENANCE.md](../../test-fixtures/PROVENANCE.md)

## 1. What this report closes

Three items were outstanding when the 6.7B session ended; all three are now
closed:

1. The five failing `tests/postmessage-interop.test.js` tests (the "handshake
   gating mismatch") — resolved 2026-09-15, committed in `745912e` (§3).
2. The packaged standalone-build verification (6.7B report §K.14) — performed
   2026-09-15 (§4).
3. Source/fixture provenance for the SciFi-XZBT fixture — re-verified, and
   extended with the packaging record (§5).

The final two fixture-level presentation corrections are included in the
accepted baseline: the embedded Observation surface owns its NGN pane geometry,
and an orphaned Observation URL presents an inert waiting state without
creating authority.

## 2. Step 6.7 delivery summary

SciFi-XZBT remains one document with two boot modes (`js/surface-mode.js`),
advertising a Contract 5.3 Observation presentation surface as a query-mode
view of its own `index.html` (`?surface=observation&xi=<instanceId>`, the
§31.4 form that keeps the surface inside the single-file build). Console mode
owns the single Contract 5.3 session, the one authoritative SciFi state, and
an instance-scoped `BroadcastChannel` bridge (`js/surface-bus.js`); an
Observation document attaches to that authority and never creates a second
one. Two new canonical targets (`view.pillars`, `view.warp-flight`) carry the
surface control path, and the heavy subsystems (WebLLM/Kokoro experience,
visualizer, control bus, contract adapter, hotkeys, sleep timer) remain
console-only, guarded by `isConsoleMode`.

NGN `src/**` was not modified by Step 6.7B: NGN renders whatever surface
catalog `describe()` advertises, generically. New focused coverage from 6.7B
is `tests/scifi-surfaces.test.js` (24 tests) and `tests/local-surfaces.test.js`
(20 tests, one driving SciFi's real descriptors); both are part of the
full-suite run recorded in §7.

## 3. Handshake defect: root cause and correction

**Root cause.** `js/contract-adapter.js`'s `_setupWindowBridge` admitted
inbound messages only when the advisory envelope field matched exactly:
`… e.data.xzbt !== '5.2'` → return. NGN's host stamps outgoing envelopes
`xzbt: '5.3'` (`src/host.js`, since Step 6.3). The adapter therefore silently
dropped the host's `hello` and every message after it; NGN's request timeout
produced four `hello timed out` interop failures. The fifth failure was the
existing static regression guard doing its job: an exact-string comparison
against the advisory field existed in a maintained file.

**Contributing defect.** The same adapter advertised `contractMinor = 2` and
product version `'5.2.0'` while already implementing the Contract 5.3-only
`surfaces` field in `describe()`, so the two interop assertions expecting
`contract.minor === 3` could not pass either.

**Correction** (in `G:/.vibe/SciFi-XZBT/js/contract-adapter.js`, then copied
verbatim into the fixture): the inbound filter now checks only the advisory
field's presence and type (`typeof e.data.xzbt !== 'string'`) — matching the
host's own envelope validation — and the adapter advertises
`contractMinor = 3` / `version = '5.3.0'`. Four lines in one file changed:
the header comment, `version`, `contractMinor`, and the filter. The outbound
advisory `xzbt: '5.2'` stamps were deliberately left unchanged (advisory
only; no receiver gates on the value; SciFi's own browser harness reads the
envelope as-is).

**Coverage.** The fix's behavior is pinned by `tests/postmessage-interop.test.js`'s
static guard ("no maintained bridge source gates on exact equality against the
advisory `xzbt` field") plus its two behavioral regression tests that
negotiate an *unexpected* advisory tag — the same tests that were failing.
No test was added or weakened for this correction.

## 4. Packaged standalone verification (this pass)

`tools/package.ps1` was run against the SciFi-XZBT source tree
(`powershell -ExecutionPolicy Bypass -File .\tools\package.ps1 -Force`, exit
code 0). It regenerated `dist/SciFiAmbientDisplay_V179b9db.html`, replacing a
pre-6.7B build (SHA-256
`B441820627D3FB23994D129B7425D781797E705867AC02967F96846B243435D4`; a
byte-identical copy of that pre-6.7B content is retained as
`dist/SciFiAmbientDisplay_Va723f46=1.html`). The new artifact:

- 920,730 bytes; 12 script blocks + 1 style block inlined
- SHA-256 `DFD9A91CB04CABD7BD6AAA53DA0FA7A641DBB21E3B3E11FAF3EC75946D6FA271`
- mirrored verbatim into `test-fixtures/reference-exhibits/scifi/dist/`
  (both copies byte-identical)

Verification performed on the regenerated artifact:

- **Inlining** (6.7B report risk R7: inlining failure is silent): every one of
  the 13 inputs is present as a contiguous byte-identical block after newline
  normalization; the built file contains zero `<script src=`, `<link href=`,
  or `<img src=` references; the two 6.7B scripts are inlined in `index.html`
  order; the corrected handshake filter is present and no exact advisory
  comparison remains anywhere in the file.
- **Standalone boot (`file://`)**: loads complete with 12 inline scripts
  (none with `src`), zero `<link>` elements, and one inlined stylesheet; the
  console UI renders (universe selector, 7 preset buttons, themed layout,
  canvases); `window.xzbtContractAdapter` advertises contract 5/3, version
  `5.3.0`, and the two-entry surface catalog.
- **Handshake over the served path**: served from
  `http://127.0.0.1:4173/test-fixtures/reference-exhibits/scifi/dist/…` — the
  same origin and tree NGN serves fixtures from — a same-origin host
  simulation stamped `xzbt: '5.3'` completed `hello` → `describe` →
  `state.get`: contract `{major: 5, minor: 3}`, exhibit version `5.3.0`,
  63 targets, both surfaces, and a state snapshot. This is precisely the
  exchange the pre-fix build silently dropped.
- **Boundary observed**: from `file://` the same probe gets no reply, because
  the adapter's origin guard rejects it (Chrome reports `e.origin` as
  `"null"` for `file://` documents). That is the designed same-origin/self
  safety filter — NGN attaches exhibits over `http://` only — not a defect,
  and it was not changed.

Filename caveat: the artifact's name carries SciFi-XZBT's HEAD commit
`179b9db`, but the build reads the working tree, which is ahead of that
commit (that repo's contract work, including the adapter correction, is still
uncommitted there — §9). The artifact is a snapshot of the working tree, not
of a single commit.

Environmental note: an `npm start` server was already running on
`http://127.0.0.1:4173` and served the artifact; this pass neither started
nor stopped a server.

Raw outputs: [step6.7-packaging.txt](../../test-fixtures/evidence/step6.7-packaging.txt).

## 5. Source/fixture provenance check

Re-verified after the packaging pass:

- `test-fixtures/reference-exhibits/scifi/` and `G:/.vibe/SciFi-XZBT/` are
  file-set identical for the deployable surface: the 13 `js/` + `css/` files
  and `index.html`, no extras and no omissions, every file byte-identical
  (per-file SHA-256 comparison).
- The regenerated `dist/` artifact is mirrored byte-identically (§4).
- The handshake correction is present in the authoritative adapter and the
  fixture copy alike; the one-directional source → fixture flow, including
  this packaging pass, is recorded in
  [PROVENANCE.md](../../test-fixtures/PROVENANCE.md).
- One cosmetic artifact is mirrored along with the content: `index.html`
  carries trailing whitespace on four script lines added by 6.7B. It predates
  this pass, is byte-identical in both trees, and was left unchanged to
  preserve that byte-identity.

## 6. Contract-policy confirmation

- Maintained contract: **major 5, minor 3**. NGN's host stamps the advisory
  `xzbt: '5.3'` and admits exhibits on the negotiated contract fields
  (`supportedContractMajors`, `contract.major`, integer `contract.minor`).
- The advisory `xzbt` field is **not** a compatibility gate anywhere in
  maintained paths: a repo-wide static scan for exact comparisons against it
  returns zero hits in `src/`, `tests/`, `public/`, `server/`, and the
  maintained reference exhibit sources (generated `dist/` builds and the
  git-ignored `test-fixtures/local/` copies excluded; the retained pre-6.7B
  artifact still contains the old comparison but is a build, not a maintained
  source path).
- Maintained exhibits advertise 5/3: the shared `contract-core.js` default,
  Museum Gallery, and SciFi-XZBT. Aquarium, Haunted House, and Planetarium
  declare no surface catalog (optional per §31; unchanged by 6.7).
- Compatibility with a genuine 5.2 exhibit remains the contract's own §28.2
  guarantee and was not altered; no maintained exhibit is pinned to 5.2.

## 7. Verification totals (2026-09-15)

| Check | Result |
| --- | --- |
| NGN full suite (`node --test`) | **154 / 154** pass, 0 fail, 0 skipped |
| `tests/postmessage-interop.test.js` | **7 / 7** (was 2 / 7) |
| `tests/scifi-surfaces.test.js` (inside the full run) | 24 / 24 |
| `tests/local-surfaces.test.js` (inside the full run) | 20 / 20 |
| SciFi Observation surface smoke suite | **24 / 24** pass |
| SciFi-XZBT contract harness | 21 / 21 |
| SciFi-XZBT real-adapter suite | 32 / 32 |
| `python devlog_editor.py --validate` | devlog is valid |
| `git diff --check` | clean for this pass's files |
| Packaged artifact, structural + runtime | §4 above |

## 8. Files changed by this closure pass

Documentation, evidence, and generated artifacts only (left uncommitted; no
commit was requested):

- `test-fixtures/PROVENANCE.md` — packaging record added; two stale statements
  corrected (the resync's version-bump claim; the "dist/ not regenerated" note)
- `README.md` — Step 6.7 status line added; the SciFi surface declaration
  corrected (it now declares two surfaces)
- `docs/reference/XZBT-NGN-Step6.7-SciFi-Surface-Adaptation.md` — dated status
  updates in the header, §H, §J, §M, and the verdict
- `docs/reference/XZBT-NGN-Step6.7-Closure-Report.md` — this report
- `test-fixtures/evidence/step6.7-packaging.txt` — raw verification outputs
- `test-fixtures/reference-exhibits/scifi/dist/SciFiAmbientDisplay_V179b9db.html`
  — regenerated (git-ignored artifact)
- `G:/.vibe/SciFi-XZBT/dist/SciFiAmbientDisplay_V179b9db.html` — regenerated
  (outside this repository)

The handshake correction that this report closes was committed earlier as part
of `745912e` ("Steps 6.4-6.7B …"), pushed to `origin/main`.

## 9. Accepted live verification

The final live NGN verification passed these eight points:

1. The SciFi fixture connected and synchronized as Contract 5.3 with its expected target catalog and two-surface descriptor set.
2. The Observation pane opened into the current universe and preset, filled its NGN pane at the intended presentation geometry, and retained visible controls.
3. The pane showed no return controls, stayed inert to background clicks, and did not black out the console or change `view.observation`.
4. The seven presentation targets converged across console and pane with advancing `stateRevision`.
5. Reload and close/reopen returned the pane to current state without participant-count ratcheting.
6. WATCH EXPERIENCE affected only the console overlay; the separate Observation pane remained independent.
7. The Observation frame remained non-authoritative: no WebLLM/Kokoro activity, `window.generativeExperience`, or `AudioContext` was created there.
8. Transient activity events appeared on console and pane at the same moment; disconnect/reconnect gave clean pane release and rediscovery; standalone two-window attachment (`index.html?surface=observation&xi=<real id>` with no NGN present) mirrored correctly; and the orphan URL (`?surface=observation&xi=nonexistent`) showed the inert waiting state and created no local authority.

The console's existing 16:9-lock checkbox behavior is pre-existing presentation
behavior, not a Contract 5.3 or Observation-surface authority defect. The
accepted embedding correction is deliberately scoped to prevent that console
overlay behavior from escaping into the embedded NGN pane.

Acceptance above is not gated on §10: none of the deferred items bear on
Contract 5.3 compliance, surface authority, or the correction this report
closes.

## 10. Deferred operator verification (non-blocking)

Four checks from the 6.7B report §15 acceptance procedure call for sustained
human observation (audio quality, felt timing) rather than a scripted pass/fail,
and were not exercised in this pass. They do not block Contract 5.3 acceptance
above and are tracked here to be performed separately by an operator:

1. **Packaged single-file/offline behavior** — open the packaged `dist/`
   artifact directly (`file://`, no server) and interact with it directly:
   hotkeys, WATCH EXPERIENCE, and audio playback (report §15, steps 11 and 14).
   Only the packaged boot and structural inlining were verified in this pass
   (§4); direct offline interaction was not.
2. **Audible sound duplication/quality** — with the Observation pane open
   alongside the console, confirm audio is not audibly duplicated between the
   two and that playback quality is unaffected by the pane's presence.
3. **Generated AI announcement timing** — confirm AI-generated announcements
   remain acceptably timed (not delayed or overlapping) as they appear on both
   console and pane (report §15, step 9 covered simultaneity; felt timing
   quality was not separately assessed).
4. **Longer-running ambient-event coexistence** — over a longer session than
   this pass exercised, confirm ambient/transient events continue to
   coexist correctly across console and pane without drift, duplication, or
   missed events.

*(Note: Step 6.8 was subsequently completed and accepted with an unreproduced
session renegotiation tracked as non-blocking follow-up; Step 6 is closed at
Step 6.10.)* The retained pre-6.7B artifact
`dist/SciFiAmbientDisplay_Va723f46=1.html` should not be distributed.