Status: accepted

Accepted — merged with intent to implement.

RFC 0124: Require an explicit rule-set declaration in every source representation

Resolution

Accepted as drafted by the UWMD maintainers on 2026-10-22 (fourth set). Require UW Lite to declare uw_version. Retain the owner-confirmed RFC 0111 implementation decisions: RCP-13 for receipt/record rule-set disagreement and refusal of a model naming no kept rule set. This implementation closes Lite's implicit 3.0 selection; it does not authorize a release or add a second rule set.

Contract

UW Lite frontmatter MUST contain a non-null uw_version naming a rule set the reader/verifier keeps. The existing Format scalar version semantics apply. The Lite bridge MUST carry that declared version into the envelope and MUST NOT choose the current version or 3.0 when the field is absent. uw_lite_version names the representation grammar and cannot select the financial rule set.

A missing, null, malformed or unsupported declaration uses the existing typed UNSUPPORTED_FORMAT_VERSION refusal consistently across Lite parsing/compilation, validation, canonicalization, receipts, registered-source readers and standalone adapters. Do not author a declaration merely by reading or converting a source. Creation tools may write an explicit version when producing a new record.

Retain refusal of an API model naming no kept rule set, rather than validating it under a default. A verifier selects from the record, never the receipt. A receipt rule_set mismatch remains failed/RCP-13 before pack/backend/math indeterminacy, with no engine-identity escape. A subject that cannot canonicalize because its declaration is unsupported remains RCP-09 at the receipt boundary.

This supersedes only RFC 0081 D12's undeclared-Lite fallback. It adds no old- version reader, retention obligation for prelaunch documents or repair path. RFC 0111's already accepted post-launch rule-set retention remains separate.

Decisions

Question	Recommendation	Precedent
Undeclared Lite pins old rules or drifts to current?	Neither; require uw_version	Accepted resolution; RFC 0111 selects rules from the record
Keep RCP-13?	Yes, including existing precedence	Owner confirmed the subject-identity comparison
Model without a kept rule set?	Typed refusal	Owner confirmation; no implicit financial behavior
Representation version selects rules?	No	Format/representation versions are distinct contracts

Implementation and conformance

Update UW Lite 3/7, Format representation notes, Protocol rule-set selection, Receipt 5.2.2, frontmatter schema descriptions and executable mirrors together. Remove the bridge fallback and update current Lite creation examples/fixtures to state uw_version explicitly. Add portable controls for missing/null/malformed/ unsupported declarations, explicit supported declarations through each reader, model API refusals and receipt RCP-13/RCP-09 precedence. Update the independent Python Lite adapter and shared cases. The independent Python source reader already requires the declaration. It has no Lite financial compiler/capability; source-level refusal controls are added without claiming one.