Transcript compatibility and evolution

Part of the termverify.transcript/v1 protocol.

termverify.transcript/v1 readers must reject a different protocol value.

Whether the protocols are frozen is a governance decision, not a property of this page: the current stage, its rationale, and its exit criterion are recorded in prototyping-stage-protocol-governance.md.

While the prototyping stage lasts, the in-place amendment policy applies to every TermVerify protocol and registry (termverify.transcript/v1, termverify.key/v1, termverify.key-encoding/v1, and the JSONL control protocol): reviewed contract corrections — including incompatible ones — update the current version in place rather than creating fictional compatibility history. No version bump, compatibility shim, or per-change exception decision is required. Existing repository fixtures are migrated in the same reviewed change, and the protocol pages are updated in the same change. No backward compatibility is owed to any artifact, including the published 0.1.0; version identifiers such as /v1 name the current shape so readers can reject foreign input, and are not stability promises.

The prototyping stage ends only by an explicit recorded owner decision that TermVerify is usable by external clients — not by any release or publication event. After that boundary, only optional x- extensions are additive within a version, and new generic semantics, member types or meanings, canonicalization, ordering rules, or stable error codes require a new protocol version; the same applies to termverify.key/v1 membership, spelling, component roles, modifier ordering, and chord validity, for which ambient toolkit or host registry growth never changes a published version.

A v1 transcript without subject is invalid and no tool may guess its identity from ambient or undocumented out-of-band context. A caller with the required stable selectors may explicitly reconstruct a current v1 transcript; automatic migration is outside the codec. A future new version supplies its own fixtures and migration/replay policy. A reader may preserve unknown x- members when rewriting a transcript, but must not manufacture or interpret them.