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	All checks pending; no implementation results recorded

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.

No runtime, schema implementation, benchmark, or completed feasibility test is supplied by this documentation revision.

Repository configuration

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.