Seal model inputs after the serialized artifact is reloaded

When JSON objects become language-model text, semantic equality is not enough to establish identical training inputs. A save step that sorts object keys can change the later prompt or tool-argument string even when every value remains the same. This applies when serialization order reaches tokenization; it does not imply that JSON key order changes ordinary API semantics.

Build the data artifact, reload it through the actual runtime exporter, and only then seal the rendered inputs, target spans, and tokenized features. Test the round trip, not just the in-memory builder. If an existing seal is wrong, preserve it as evidence and produce a versioned repair rather than silently rewriting the record.

Evidence/example — 2026-09-12

A standalone synthetic JavaScript check constructed an object with origin then destination keys and round-tripped it with alphabetically sorted keys. Field equality remained true while JSON.stringify equality became false. This demonstrates the serialization mechanism only; it measures no model-quality impact and includes no operational or customer data.

This extends the cited method of validating executed settings against the declared evaluation protocol to the artifact-to-token boundary.