Architect drift review over 02fe891..f37b2a3 (firing-policies-and-merge):
drift_found, all medium/low, no contract violation. Invariants hold: C1 (the
merge is a deterministic linear scan, strict < on (timestamp, source-index) gives
C4 tie-break by declaration order; only per-call allocs), C3 (one merge at
ingestion), C5/C6 (both rails proven with worked vectors; sample-and-hold falls
out of the push model), C7 (type-erased edges, no dyn-Any/Rc/RefCell — purity grep
clean). Resolved the 0003 forward-note: cycle_id is now a real read field (the
freshness epoch, fresh_at == cycle_id), not write-only.
Resolved [med] (test gap): the barrier's timestamp token was proven only for the
multi-source same-timestamp case; C6's within-source diamond rejoin (one source,
two unequal-latency paths rejoining at a barrier) was claimed by the spec but
untested. Added `within_source_diamond_rejoin_barrier_fires`
(source -> {SMA(2), SMA(4)} -> BarrierSum): once SMA(4) warms at cycle 4, both
paths emit each cycle at the same timestamp and the barrier fires
(15+13, 17+15, 19+17). The code was already correct — every push in a cycle
stamps last_ts = that cycle's timestamp (source pushes and produced-edge forwards
alike) — so this closes the coverage gap, not a bug.
Resolved [med] (glossary record-reality): the run-count entry claimed it "drives
freshness-gated recompute", now false — the engine's firing gate reads the
per-wiring-slot cycle epoch (fresh_at), not Column::run_count. Sharpened the entry
to record reality: run-count is the node-visible per-column push counter;
fresh_at is the engine's per-slot freshness epoch. Not redundant (different
levels); both are maintained consistently on every push.
Resolved [low] (ledger silent on the barrier token): added a C6 "Realization
(cycle 0004)" note recording the load-bearing decision — barrier token is the
timestamp not cycle_id (forced by C4's same-timestamp-tie rule), firing tagged
per input with Firing::{Any, Barrier(u8)}, a mode-A input being its own trivial
group (so "per input group" and the per-input tag coincide).
Carry-on forward notes (next-cycle owners, not fixes now):
- [low] cycle_id is materialized internally (the freshness epoch) but not yet
surfaced in run output (run returns Vec<Option<Scalar>>). Its first observable
consumer is a sink / clock node (C18) or a timestamped trace — materialize the
surfacing then.
- [low] all join fixtures declare lookback 1; a test guarding C8's "a node never
reads beyond its declared lookback" for a depth>1 join is still owed (the
substrate already enforces it via Window bounds, so this is confirmation, not a
hole).
Regression gate: profile regression list empty — architect is the sole gate, now
clean (31 tests: aura-core 19 + aura-std 3 + aura-engine 9; clippy -D warnings
clean; purity grep clean). Cycle 0004 is drift-clean. NOT a milestone close: the
walking-skeleton milestone still needs its end-to-end fieldtest (ingest -> signal
-> backtest -> position table -> broker -> pip-equity), of which this cycle
delivers the firing/merge layer.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Brummel
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