0064: Binding boundary error categories

Status: accepted for the 0.7 development SDK.

Decision

Python boundary failures use the public exception hierarchy and C error codes. Required unknown native tags or an incompatible ABI raise UnsupportedError. Known tags with inconsistent payloads, missing required outputs or invalid native text raise InternalError. Operations on closed owners or terminal edits raise InvalidArgumentError. Check ABI compatibility before configuring its operation signatures.

Ordinary Python type mistakes still raise TypeError; library discovery keeps its existing filesystem/configuration exceptions. Cleanup remains idempotent. The C++ decoder likewise rejects unknown closed tags with unsupported, including metadata, conflicts, jobs, resolution, artifact state and receipts. Open-world strings remain extensible. An inconsistent commit receipt fails after a terminal commit attempt; it must never be retried on that edit.

The native boundary remains authoritative for operation errors. Optional unknown vocabulary and authored external facts continue to round-trip.

Standards impact

No schema, standards mapping or serialized identity changes. The categories describe binding and ABI failures, not interpretation of external media facts.