# XZBT 0.1 Verification Gates

**Status:** Phase 0 shared-contract preparation complete before Phase 1. GC1 direct-file feasibility and GC2–GC5 shared contracts are verified; subsystem integration gates remain in their assigned later phases.
**Related resources:** [PRD](../XZBT_0-1_MVP_Product_Requirements_Document.md), [decisions](XZBT_0-1_Gap_Closure_Decisions.md), [format specification](XZBT_0-1_Format_Specification.md)

A separate Phase 0 probe has been created and its JavaScript/JSON syntax checked. The agent's direct-file navigation was blocked by browser tool policy; see the [attempt record](evidence/phase0/2026-09-04-feasibility.md). The [user's manual run](evidence/phase0/2026-09-04-user-run.md) reports successful import, saves, and context unlock, but worklet loading failed. Version 2 separates the tests and records better diagnostics; its two stubbed regression tests pass, not its browser gate. Mark a check complete only with linked evidence; a partial result does not pass a compound acceptance check.

The [second user run](evidence/phase0/2026-09-04-user-run-v2.md) confirmed cache restoration between page loads, a heard tone, and audio suspend/resume, but Blob worklet loading failed. The [version 3 user run](evidence/phase0/2026-09-04-user-run-v3.md) verified the embedded-data-URL fix. The subsequent [manual restart test](evidence/phase0/2026-09-04-user-restart.md), supplied after the explicit full-exit procedure, restored edited activity and volume with zero new saves. The [directory fallback observation](evidence/phase0/2026-09-05-user-directory-fallback.md) confirmed graceful error handling and state preservation when directory access is cancelled/denied; GC1 is fully passed. GC2 schema/semantic validation and its 12-case matrix are verified in the [GC2 evidence](evidence/phase0/2026-09-05-gc2-format-contracts.md). GC3–GC5 shared resolution, clock/PRNG, and ownership/failure contracts and deterministic traces are verified in the [combined contract evidence](evidence/phase0/2026-09-05-gc3-gc5-contracts.md).

## Phase 0 and later gates

The [implementation plan](XZBT_0-1_Implementation_Plan.md) is complete and Phase 1 may begin. GC1 and the shared portions of GC2–GC5 are satisfied. Early GC6 measurements still precede expensive subsystem optimization decisions. Full production conformance and real-duration soak results remain later requirements.

Subsystem-specific format details can be completed in dependency order as planned tasks. Do not require the finished engine or eight-hour soak before creating the plan.

| Gap | Decision | Evidence status | Gate placement |
| --- | --- | --- | --- |
| GC1 | Recorded | Passed; all 10 direct-file feasibility checks verified with linked empirical evidence | Phase 0, before deployment architecture commitment |
| GC2 | Recorded; shared contracts complete | Shared document, types, ValueSpec, ConditionSpec, schema, validator, and 12-case fixture suite verified; subsystem contracts in dependency order | Shared contracts in Phase 0; subsystem contracts before their implementation |
| GC3 | Recorded; shared transition rules complete | Deterministic resolver traces pass | Shared resolver contract complete; repeat with Phase 2 implementation |
| GC4 | Recorded; shared clock/audio mapping/PRNG complete | Deterministic clock, unlock-decision, and stream tests pass | Clock contract complete; real synchronization tests in audio integration |
| GC5 | Recorded; shared lifecycle rules complete | Deterministic ownership/failure traces pass | Ownership contract complete; repeat with real actions/audio/scenarios |
| GC6 | Recorded; thresholds provisional | Measurement protocol and schedule defined; reference setup/benchmark results pending | Early combined-load prototype; development and release acceptance |
| GC7 | Recorded; identity/update/build boundary complete | Milestone map complete; implementation checks pending | Planning complete; then library/build integration |

## 1. GC1: Direct-file feasibility

- [x] Record OS, browser version/profile, launch path, and storage mode. The preceding environment records and [regular-Chrome confirmation](evidence/phase0/2026-09-04-user-import-environment.md) establish Windows, Chrome 152, direct-file launch, and IndexedDB in a regular non-Incognito profile.
- [x] Open the artifact directly from disk with network unavailable. The [follow-up capture and user confirmation](evidence/phase0/2026-09-04-user-offline-audio.md) verify restoration, tone, and worklet with browser-scoped Offline mode enabled. The changed mobile user agent on Win32 does not establish physical Android support.
- [x] Import two exhibits with the ordinary file picker and activate each. [The user confirmed ordinary import and selection of both fixtures worked](evidence/phase0/2026-09-04-user-import-environment.md).
- [x] Save exhibit definitions, per-exhibit parameters, selection, and master volume to IndexedDB. See the version 1 saves and subsequent restored snapshots, including edited values in the restart record.
- [x] Close the browser fully, reopen the same HTML, and restore the cached library and settings without selecting source files again. Passed as user-performed evidence following the explicit full-exit procedure; see the restart record for provenance and limits.
- [x] Verify user-initiated audio unlock and resumed playback. Native tone heard in versions 2/3; AudioContext suspend/resume states observed in version 2. This is not full audio-engine conformance.
- [x] If needed by the audio design, load engine-owned AudioWorklet code from the single-file artifact. Verified with the data-URL module in the version 3 user run.
- [x] Test renamed and moved HTML files; record observed storage behavior and the support boundary. The user confirmed restoration from both copies; see [file-location evidence and limits](evidence/phase0/2026-09-04-user-file-locations.md).
- [x] Test unavailable/failed storage; session playback works and the UI explains lack of persistence. [Injected-failure evidence](evidence/phase0/2026-09-04-user-storage-failure.md) confirms settings changes, import, and heard native playback remain operational with zero successful writes; the user subsequently confirmed the visible session-only warning. Passed using application fault injection, not real browser permission denial.
- [x] Test directory import/remembered handles where available and ordinary-picker fallback where unavailable or permission is denied. Directory import completed in the injected-failure run and ordinary import/activation passed separately. Directory cancellation/denial fallback is verified with preserved session state; see [directory fallback evidence](evidence/phase0/2026-09-05-user-directory-fallback.md). Remembered handles are optional and not implemented in this probe; verification is required if implemented in the runtime.

**Evidence:** prototype artifact, reproducible steps, environment record, observed results. If ordinary-mode persistence fails, reopen decision 1 before dependent architecture commitment.

## 2. GC2: Format contract completeness

- [x] Complete shared document, type, reference, ValueSpec, ConditionSpec, time, and ownership contracts. Formalized in [Format Specification Rev 0.2](XZBT_0-1_Format_Specification.md).
- [x] Fill the format-specification contract register in subsystem dependency order. Document/schema and Values/conditions completed.
- [x] Implement an internal structural schema plus separate semantic validation. Schema authored in [schema/xzbt-0.1.schema.json](../schema/xzbt-0.1.schema.json), validator implemented in [tools/validate-exhibit.mjs](../tools/validate-exhibit.mjs).
- [x] Provide complete valid and invalid fixtures with expected diagnostics. See [test/fixtures/gc2/](../test/fixtures/gc2/) and [GC2 evidence](evidence/phase0/2026-09-05-gc2-format-contracts.md).
- [x] Reject unsupported versions, unknown behavior fields, invalid reference types, recursive components, illegal graph cycles, and excessive resources. Verified with 12/12 passing automated test matrix in [test/gc2-runner.test.mjs](../test/gc2-runner.test.mjs).
- [ ] Produce two contrasting complete audiovisual exhibits early; expand toward all PRD challenge cases. Minimal and full feature test fixtures created; full audiovisual reference exhibits belong to Phase 1/Phase 9.
- [x] Reconcile prior conversation proposals into the local documents; resolve conflicts explicitly. Reconciled into local format specification Revision 0.2.

**Evidence:** versioned specification/schema/fixtures and validation results in [2026-09-05-gc2-format-contracts.md](evidence/phase0/2026-09-05-gc2-format-contracts.md). Naming a node or behavior does not close its contract.

## 3. GC3: Resolution semantics

- [x] Record exact target capabilities, override defaults, smoothing, and interrupted transition rules.
- [x] Define expected traces for a bound bus gain receiving a direct override.
- [x] Define expected traces for a parameter override feeding a binding.
- [x] Verify stored user edits during masking and release toward the updated lower value.
- [x] Verify priority ties and competing duration/scenario overrides.
- [x] Verify automation continues while masked and permitted modulation applies after an override.
- [x] Verify numeric clamps and unsupported target/stage diagnostics.
- [x] Reject conflicting bindings and dependency cycles without introducing undocumented delays.

**Evidence:** [GC3–GC5 shared contract evidence](evidence/phase0/2026-09-05-gc3-gc5-contracts.md), executable resolution model, normative JSON traces, and deterministic resolver tests. Production resolver conformance repeats in Phase 2.

## 4. GC4: Time and reproducibility

- [x] Define logical tick ordering, maximum work per turn, long-stall behavior, audio lookahead, and audio unlock alignment.
- [x] Define PRNG algorithm, seed normalization, and stream derivation for the runtime version.
- [x] Compare simulation traces at different render frequencies using the same logical inputs.
- [x] Simulate hide/restore and explicit pause/resume; no missed wall-clock work is replayed. Repeat with the Phase 1 runtime in a browser.
- [x] Verify in the clock model that visibility restoration does not undo an explicit pause.
- [x] Verify audio suspend/resume in the GC1 browser probe and verify pre-unlock one-shot suppression in the deterministic scheduling model. Repeat combined behavior during audio integration.
- [x] Verify manual SAMPLE does not perturb cadence/scenario random streams.
- [x] Use deterministic signal fixtures for audio-reactive decision tests.
- [x] Distinguish accelerated logical tests from real-time audio behavior and soak tests.

**Evidence:** [GC3–GC5 shared contract evidence](evidence/phase0/2026-09-05-gc3-gc5-contracts.md), clock/PRNG model and known vectors, logical traces, deterministic signal fixture, plus the earlier GC1 browser audio observations. This closes the Phase 0 contract gate, not later real-time synchronization or soak gates. No cross-device pixel or waveform equality claim is required.

## 5. GC5: Ownership and failure

- [x] Define hook ordering, allowed hook actions, failure propagation, cleanup deadlines, deferred expiry/order, and dispatch-budget behavior.
- [x] Start resources through nested events and confirm inherited scenario ownership.
- [x] Verify duration overrides terminate with their owner and bounded releases eventually dispose.
- [x] Verify persistent state mutations survive a later critical failure.
- [x] Inject failures into startup, ordinary actions, and termination hooks; cleanup still completes.
- [x] Verify condition triggers require a false condition before rearming.
- [x] Verify at most one pending deferred request per definition, expiry, and eligibility recheck.
- [x] Exercise event/scenario feedback and show bounded dispatch with diagnostics.
- [x] Repeat completion/cancellation/failure cycles; counters return to baseline after releases finish.

**Evidence:** [GC3–GC5 shared contract evidence](evidence/phase0/2026-09-05-gc3-gc5-contracts.md), lifecycle oracle, resource-count assertions, and failure-injection tests. Repeat with subsystem-owned resources during Phases 3–6.

## 6. GC6: Performance and audio acceptance

- [ ] Record CPU/GPU/RAM, OS, browser version, 1920 x 1080 viewport, device-pixel ratio, sample rate, and relevant power settings.
- [ ] Fix benchmark exhibit/version/seed and counts for particles, links, trails, effect passes, audio nodes, and concurrent voices.
- [ ] Prototype combined visual/audio load early and record supported limits.
- [x] Define warm-up duration, measurement window, frame interval sampling, and retained-memory sampling method before collecting acceptance data. See the implementation plan; no benchmark result is claimed yet.
- [ ] Check the provisional p95 frame interval threshold of less than 33.3 ms and report progress toward the 60 FPS target.
- [ ] Record active resource baselines and verify expected return after repeated lifecycle operations.
- [ ] Specify and test digital output peak ceiling, numerical tolerance, finite samples, release behavior, and unavoidable master routing.
- [ ] Stress overlapping recipes and listen for clicks, clipping, and objectionable release artifacts.
- [ ] Run a two-hour development soak and an eight-hour release soak; record retained-memory trends, resource counts, frame intervals, audio glitches, and scheduler growth.

**Evidence:** fixed workload, environment, measurement method, results, and investigated anomalies. Any threshold revision must be recorded before rerunning acceptance; do not silently change the benchmark to produce a pass.

## 7. GC7: Scope, updates, and build

- [x] Map all PRD completion criteria and challenge cases to milestones and evidence.
- [ ] Integrate two contrasting exhibits early; make Phase 9 the completion/audit phase for all five reference exhibits.
- [x] Define import equality and parameter compatibility precisely.
- [ ] Verify identical imports are no-ops and changed same-ID content requires an explicit replacement choice.
- [ ] Verify invalid refreshes leave the last valid definition and configuration intact.
- [ ] Verify compatible parameter preservation, numeric bound changes with notice, removed/new parameters, and incompatible-type/enum resets.
- [ ] Validate and prepare a candidate without observable playback before stopping the working exhibit.
- [ ] Inject activation failure; dispose of the candidate and attempt a fresh restart of the previous exhibit with saved settings.
- [ ] Build separate source modules into one self-contained HTML artifact reproducibly.
- [ ] Test the delivered artifact directly and offline; no external runtime scripts, modules, assets, fonts, or CDN requests are required.

**Evidence:** implementation-plan coverage, library failure tests, build instructions, and artifact verification.

## Evidence record template

For each result, record gate/check ID, date, specification revision, implementation revision or artifact hash, environment, fixture/seed, procedure, expected result, actual result, pass/fail/not-applicable status, linked logs or measurements, and unresolved limitations. A not-applicable result requires a reason. Do not prefill results from intended behavior.