The Rust interpreter remains the operational reference; versioned adapters expose Rust, LIL, and LIT through one fail-closed observation contract on their declared v1.5 surfaces.
Current guarantees
- Evaluation uses explicit outcomes, signals, and a trampoline instead of host unwind.
- Backend descriptors record interpreter kind, invocation protocol, artifact identity, supported axes, provenance, and resource profile.
- External admission is fail-closed. The joint receipt binds each of the 144 cases to executed Rust, LIL, and LIT product-runner artifacts, limits, observations, and replay.
- Vouch product capabilities are surface-specific: Native provides source identity, policy tooling, issuance, authentication, re-execution, a local gate, and inspection; npm provides source identity, policy tooling, authentication, inspection, and corpus replay; WASM and Playground evaluate without exposing Vouch.
Runner admission fields
| Field | Requirement | Rejection boundary |
|---|---|---|
| backend kind | interpreter | compiler kind rejected |
| invocation | versioned command/protocol with deterministic framing | malformed, duplicate, unsolicited, or version-drift response |
| artifact identity | executed binary/WASM/glue bytes identified | recorded identity differs from executed artifact |
| provenance | declared same-origin/external status | silent upgrade to independent witness |
| resource profile | named limits and report support | uniform-threshold overclaim |
| admitted scope | exact versioned corpus, implementation family, and host variant | silent widening from a bounded observation to a backend-wide or whole-language claim |
Boundaries
- A packaging or generated-code target is not automatically a separate implementation or independent witness.
- LIT interpreter, generated Rust, generated Python, and Web routes are host variants of one Topaz source. Their internal four-host agreement does not extend the 144-case joint receipt or establish source independence.