Documentation only. No implementation.
Drafts the implementation contract for the schema-minor rung against the
ratified epoch ladder and the vocabulary audit. Ten design pins covering the
derivation (envelope max over emitted, block max over envelopes, major and
minor derived independently), the five vocabularies that need introduced_minor,
the manifest seam, and the text-projection consequence.
Three pins exist to prevent specific wrong edits. The baseline sentinel must
not be 0, because 0 is a real baseline minor for V1-V3 and conflating them
makes the max read correctly by accident. OperationKindTag's epochs go inside
operation_kind_tag_vocabulary!, not beside it, because a sibling match is the
parallel list the macro exists to prevent. And bundle.rs:301 must stay a
major-only comparison - tightening it to the full version would be a
conformance regression, and it is the most tempting wrong edit in the packet.
One pin requires ratification before implementation: epiphany-textproj cannot
detect changed barrier bytes, having no prior state to diff and no layout-ir
dependency to decode with. Recommended disposition is a documented preserving
producer, with a testkit conformance check as the alternative. The two differ
by a test rather than a design.
Fourteen tests, each with the mutation that must kill it, including the
rejected highest-discriminant policy, the over-stamp after a contributing
barrier is removed, and the bundle.rs:301 tightening.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
