Ratified 2026-07-24, resolving Ruling B blocker (i). Pass-12 K8 is reversed:
every mutable field of Score becomes operation-authored, and a document is
Score::empty(identity) plus its envelope log. The instrument, staff, staff
instance, voice, event chain is authorable end to end.
The decision removes machinery rather than adding it. Every alternative kept
genesis outside the operation set and then had to pay for that: a new chunk
role, a manifest field, an immutability rule, and a merge or fail-closed rule
for a canonical payload with no CRDT semantics. Genesis state is edited —
instruments get added, page geometry changes, temperaments are chosen — and
each alternative made those edits single-writer, unmergeable, or impossible.
Concurrency is a first-order product commitment, so the exception was not
worth institutionalising in the format.
Scope is nine surfaces over two templates already proven in reduce.rs: three
LWW settings setters on the SetMetadata pattern (canvas.layout_defaults,
tuning_context, spelling_precedence) and six entity mint families on the
CreateStaff pattern (instruments, staff_groups, parts, analysis_layers, views,
and StaffInstance.measures), each with graph-aware referential preconditions.
Delete and modify coverage is left to the tranche contract rather than assumed,
since CreateStaff itself ships today with no DeleteStaff.
Measures are ruled authored rather than derived. TimeAnchor::Measure carries a
measure id that cross-cutting structures anchor to, so deriving measures from
the metric grid would make their identity a function of the meter and every
time-signature change would orphan the anchors pointing into them. The cost
accepted is that measure/meter consistency becomes an authoring obligation
backed by a graph invariant.
Three constraints are written in rather than left implicit. Pruning may not be
implemented until the canonical base carries graph values: a prune installs a
MaterializedState base whose effects are outcomes, not payloads, so nothing
rebuilds the score afterward — silent and total, and free to prohibit now
because no prune exists to break. The from-empty path must reduce through
new_onto with an empty Score rather than base-free, because the base-free mode
skips graph-aware preconditions by design and would silently lose referential
enforcement from the first operation. And the OperationEnvelopeBlock accept-set
raise 2 to 3 is spent once, so the new kinds land as one batch — this is a
different major from Push 4b's schema major 3, the Score and Snapshot role wire
that tranche 3b-i froze, and there is no free ride between them.
The analysis is corrected in place rather than rewritten, so the evidence the
ruling rests on stays readable. Two amendments: Measure is a ninth uncovered
surface the original table missed by scoring canvas.regions at container
granularity, and identity is promoted from a stated question to a blocking one
— IdentityContext is replica-scoped yet lives on Score and is encoded, so under
from-empty reduction two replicas with an identical log produce Scores
differing in an encoded field while the music is identical. That disposition
blocks specification of the tranche and is deliberately not ruled here.
Execution belongs to the Push-4b-class coordinated track; the editor track
consumes it. T1b's lease, save, and single-writer machinery does not depend on
the tranche landing and may be contracted in parallel.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Levi Neuwirth
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