XZBT-NGN/docs/reference/XZBT-NGN-Step6.7-Closure-Report.md

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.)

• Step 6.7A (design, no code): architecture report
• Step 6.7B (implementation): implementation report
• Packaging evidence: step6.7-packaging.txt
• Fixture provenance: 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.

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.
• 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.