Invariant 20 has nine non-success paths, not the three P13-S18 recorded. Only
three are abstentions: agreement-Indeterminate, boundary-Indeterminate, and an
incomputable boundary delta. Two are delegated to invariant 10, two are vacuous,
one is inapplicable, one is P13-S19's pickup deferral. The entry had been
counting all of it as gap.
Delegation is proved, not asserted. Deleting invariant 10's per-measure arm
leaves the condition unreported by the entire workspace suite except by the two
tests that name it; the same holds for the instance-local-grid arm. A delegation
nobody discharges would have been an abstention with a better name.
Every abstention cell carries a paired positive control, because silence is the
same observation for all nine paths. Each test asserts zero violations on the
fixture that takes the claimed path, then changes only that path's dependency
and asserts the clause decides with the expected witness. The control has to
observe the clause the cell names: S8's first version restored the governing
search by moving prev, which broke prev<->x comparability and left the boundary
silent for a second reason, signing the cell by inference. Moving the grid edge
instead keeps both measures c4-comparable and the boundary clause itself fires.
S2 has no such option -- a WallClock delta is never computable -- so its control
legitimately observes prev's agreement, and that exception is S2's alone.
Three shapes claimed a clause pair no single measure exhibited: m0 carried a
resolving signature at index 0 and m1 carried None, so the pair was really
A4+B1 on one measure and A1+B4 on the other. A boolean over the whole invariant
cannot see that, which is how it survived the first pass.
No behaviour change. check_measure_meter_consistency's executable body is
byte-identical to f33673d at 4871 bytes, verified by brace-matching from the
signature rather than a sentinel; every red observation came from fixture data or
from invariant 10, never from invariant 20's own logic.
P11-C5 was never this residue's gate -- it is a re-anchoring proximity metric.
P13-S23 is filed for the real dependency: placing anchor pairs on a common
timeline and measuring musical distance wherever c1-c5 do not already yield
both. It owns two disjoint deficiencies, since c3 and c5 order without
supplying any delta.
Executed against spec/CONTRACT_P13S18_MATRIX.md, 18 cells and 10 mutations.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
PreconditionFailureReason 14 (AcousticRealizationPinned) and 15
(TranspositionOutOfRange) entered the vocabulary at Push 4a and reached this
document at neither place that owed them. The bounded enumeration ran 13 straight
to G3b's 16, and Push 4a's own history row recorded only OperationKind 30 while
saying nothing about the two reasons it appended in the same epoch. The Operation
Catalog documented both at its 0.8.0 and effect.rs has carried both throughout;
only the wire specification was silent.
This is P13-S20's specification-side twin, and it is why that decoder could stop
at 13 unchallenged: an implementer reading only the wire specification would have
built exactly that decoder and been right. No version bump and no new history
row -- this records an assignment normative since Push 4a rather than making one.
The regression test checks both sites, each bounded to its own longtable row,
because either alone is satisfiable by the wrong thing: the G3b row and the
enumeration both discuss PreconditionFailureReason at length, and an unbounded
search would go green the moment any row mentioned the names. Each half was
observed red alone while the other stayed green. The Push 4a row is located by a
version-free separator marker, per the file's standing rule against encoding a
document version number anywhere in it.
The epoch-12 evidence hash is e64a4b7, not this rung's parent. G3b landed across
six commits, and the chain records introducing commits -- the commit where
kind/tag 39 enters payload.rs and reasons 16-18 enter effect.rs -- exactly the
distinction the 2026-07-28 correction draws between 7df5ca1 and 55eff00 for G2a.
d58eee8 completes the rung and introduces no discriminant; both are named, with
their roles stated, in the plan and in the contract's pin 15.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
Kind 39 CreateMeasure and precondition reasons 16-18 reach the Binary Format's
kind table, tag table, payload layout, and reason table; graph invariant 20
reaches the core specification's enumeration, which now says twenty in all three
places it counts. Both normative listings in that document gain CreateMeasure --
earlier drafts of the contract named only the invariant, and prose fails silently.
Every version surface moves in pairs. Binary Format 0.15.0 -> 0.16.0, Operation
Catalog 0.12.0 -> 0.13.0, each with a changelog entry beside the title bump. The
Text Projection companion needed only the changelog: packet 1 bumped its header to
0.13.0 and stopped there, leaving the document claiming a version its own history
did not record. That was live from e64a4b7 until now, and no gate could see it.
Two public hooks exist that would otherwise look like leaks. epiphany-ops depends
on epiphany-core and never the reverse, so invariant 20 implements pin 6/6b's
comparable relation and musical delta a second time over the graph alone. Both
DECISIONS records name the divergence hazard that forces the duplication, name the
cross-crate agreement test as the hooks' only sanctioned use, and say so from each
side.
The monotonicity evidence chain gains only vocabulary-introducing events -- G2b
13c3d2f, G3a 6c5e69f, G3b -- and excludes G-minor and P13-S17 with the reason
stated: neither introduced an additive variant. The 2026-07-29 tie between G2b and
G3a is broken by ancestry, not timestamp.
P13-S18 (invariant 20's abstention residue) and P13-S19 (the pickup deferral) are
filed open by design. P13-S20 is recorded RESOLVED.
The genesis ladder G1 -> G2a -> G-minor -> G2b -> G3a -> G3b is CLOSED.
Executed against spec/CONTRACT_GENESIS_G3B_MEASURE.md rows 14a and 26-36,
mutation M71, which is now the contract's own guard: deleting the G3b Revision
History row fails the history test even though "genesis tranche G3b" still appears
twice in neighbouring prose.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
Kind and tag 39 at schema-minor epoch 12, in both unaligned discriminant
spaces. Measure is schema major 0 -- struct_codec! is a plain walk and
TimeAnchor's Codec has no version branching -- so schema_major() gains no arm
and OperationEnvelopeBlock stays at 3.
CreateMeasure is a nested-container mint following CreateStaffInstance, not
G3a's root-level shape: it carries the owning StaffInstanceId beside the
value, and measure_values carries that parent because Measure has no
back-pointer and the graph-removal arm will need it. Append-only, with
referential preconditions on the parent, the signature, and every non-wall-clock
start referent.
The comparable relation is five exact shapes with an identical boundary
selector; ordering across Start/End is unsound while measure length is
unresolved, so it stays unverifiable. Boundary distance needs a musical delta,
which only same-referent same-selector Musical offsets supply. The effective-grid
oracle reconstructs inheritance from metric_grid_chain and meter_change_chain by
write recency -- not by always overlaying per-key on whole-grid -- folds in
prospective overrides, and runs identically in both reduction modes, so an
instance_grid ledger keeps base-free reduction honest.
Three precondition reasons at 16-18. Repairs a live bug found in review: the
materialized-effect decoder stopped at 13, so reasons 14 and 15 already encoded
without decoding, and the generator drawing below(14) could not see them.
Executed against spec/CONTRACT_GENESIS_G3B_MEASURE.md, mutations M1-M33,
M64-M66, M67-M70. text_projection.tex moved into this packet: four tests read
it live, so the companion bump cannot be split from the grammar.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
Levi Neuwirth