XZBT is a self-contained browser runtime for declarative procedural audiovisual exhibits. XZBT.html provides capabilities; .xzbt documents define experiences.

Reading order and authority

Resource	Purpose	Status
MVP Product Requirements Document	Product scope, user behavior, delivery requirements, and release acceptance	Document revision 0.2; format version remains 0.1
Format Specification 0.1	Runtime semantics, contract inventory, and required authoring examples	Partial specification; identified contracts still require completion
Gap Closure Decisions	Decisions and rationale for the seven pre-implementation gaps	Decisions incorporated for planning; feasibility is not yet verified
Verification Gates	Evidence required before architecture commitment, subsystem work, and release	Worklet, audio, and user-performed restart persistence passed; GC1 incomplete
Implementation status	Current phase, stop reason, saved work, and resume prerequisites	Phase 0: worklet loading passed; remaining manual checks pending

The PRD is authoritative for product requirements. The format specification is authoritative for runtime semantics where a contract is explicitly defined. The decision record explains those choices; the verification gates define how to check them. These documents must be updated together when a decision changes. An unresolved conflict is a specification defect, not permission for an implementation to choose silently.

The earlier ChatGPT discussion, Discuss Application Vision (conversation 6a9b5c32-1ffc-83e8-a219-fa8113167f03), is historical design input. Its proposals must be reconciled into these local resources before they become implementation contracts. It is not a second source of executable instructions.

Planning entry point

Begin the implementation plan with Phase 0 from the verification gates. Complete the launch-model prototype and shared semantic contracts before committing dependent architecture and detailed estimates. Carry workload measurements and release soak tests as later explicit gates; they are not prerequisites for drafting a plan.

The full PRD completion criteria remain the 0.1 release target. Early integrated demonstrations are milestones, not completed MVPs. Reference exhibits develop alongside the engine; Phase 9 completes and audits the suite.

Phase 0 has begun with a separate feasibility probe and fixtures. The version 3 user-run result verifies embedded data-URL worklet loading. The subsequent user-performed restart test restored edited activity and volume. The directory-permission/unavailability fallback check remains pending; the agent cannot perform direct-file navigation through its browser tool. No production runtime, completed schema implementation, benchmark result, or completed GC1 gate is supplied yet.

Repository configuration

The storage-failure evidence additionally confirms session settings changes, directory import, and heard native playback during injected write failures. The user also confirmed the visible session-only warning; the injected-storage-failure check passed.

Copy .env.example to .env for local repository configuration. .env and its variants are ignored by Git; never commit real credentials. The example contains placeholders only.

The repository's existing LICENSE is preserved.