3-lineage scrum on 434f466..0d4f033 surfaced one convergent finding
(Opus + Kimi) and 3 Opus-only real bugs. All actioned in this
commit. Two false positives (Kimi rollback misreading, Opus stale-
comment claim) verified + rejected — both required manual control-
flow inspection to refute, matching the documented Kimi-truncation
behavior in feedback_cross_lineage_review.md.
Convergent fix — DecodeIndex lost nil-meta items:
- Envelope version bumped 1 → 2.
- New v2 field: IDs []string carries the canonical ID set
explicitly, independent of meta map's nil-vs-{} sparseness.
- DecodeIndex accepts both versions: v2 reads from env.IDs; v1
falls back to meta-key inference (with the documented
limitation that nil-meta items are invisible — preserved for
backward-compat with already-persisted indexes).
- Encode emits v2 going forward.
- 2 new regression tests:
- TestEncodeDecode_NilMetaItemsSurviveRoundTrip: items added
with nil metadata MUST survive Encode → Decode and remain
visible to IDs(). Pre-fix would have yielded IDs() == [].
- TestDecodeIndex_V1BackwardCompat: hand-crafted v1 envelope
still decodes (proves the fallback path).
Opus-only fixes:
- handleMerge: non-ErrIndexNotFound errors at h.reg.Get(name) /
h.reg.Get(req.Dest) now return 500 + log instead of falling
through with nil src/dest pointers (which would panic on the
next deref). Real bug — only the sentinel error was handled.
- internal/drift/drift.go: mathLog wrapper removed; math.Log
inlined. Wrapper added no value (math was already imported).
- internal/distillation/audit_baseline.go: BuildAuditDriftTable's
bubble sort replaced with sort.Slice. Idiomatic + shorter.
Rejected after verification:
- Kimi WARN "missing rollback on partial merge": misread the
control flow. Code at cmd/vectord/main.go:404-414 does NOT
delete from src when dest.Add fails (continue before reaching
src.Delete). Only successful Adds trigger Deletes.
- Opus INFO "TimestampUnixNano comment references missing field":
field exists at scripts/multi_coord_stress/main.go:128. Opus
saw only the diff context, not the full file.
Deferred (no fired trigger):
- Opus WARN "no per-index lock during merge": no concurrent merge
callers today (operators run merge as deliberate one-shot job).
Worth a lock if/when matrixd or chatd start auto-triggering.
Disposition: reports/scrum/_evidence/2026-05-01/verdicts/post_role_gate_v1_disposition.md.
Build + vet + tests green; 2 new regression tests + all prior tests
unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Substantial wave addressing all 4 prior OPEN items. Three closed in
full, one partially (the speculative half deliberately deferred).
OPEN #1 — Periodic fresh→main index merge (FULL):
- POST /v1/vectors/index/{src}/merge with {dest, clear_source}
- Idempotent on re-runs (existing-in-dest items skipped)
- internal/vectord/index.go: new Index.IDs() snapshot method +
i.ids tracker field as canonical ID set, independent of meta
map's nil-vs-{} sparseness (was a real bug — IDs() backed by meta
alone missed items added with nil metadata)
- 4 cmd-level integration tests (happy path drain+clear, dim
mismatch, dest not found, self-merge rejection) + 1 unit test
- DecodeIndex backward-compat: old envelopes restore i.ids from
meta keys (best effort; new items going forward use the tracker)
OPEN #2 — Distillation SFT export (SUBSTRATE):
- internal/distillation/sft_export.go ports the load-bearing half:
IsSftNever predicate + ListScoredRunFiles (data/scored-runs/YYYY/
MM/DD walk) + LoadScoredRunsFromFile + partial ExportSft.
- Synthesis (instruction/input/response generation) deferred to a
separate wave — too big for this session, but the substrate
makes the next wave a port-not-design exercise.
- TestSftNever_PinsExpectedSet locks the contamination firewall
set: if a future commit adds/removes from SftNever, this test
fails — forcing the change through review.
- 5 new tests; firewall fires end-to-end through the partial port.
OPEN #3 — Distribution drift via PSI (FULL):
- internal/drift/drift.go: ComputeDistributionDrift via Population
Stability Index. Standard finance/risk metric, well-defined
verdict tiers (stable < 0.10, minor 0.10–0.25, major ≥ 0.25).
- Equal-width bucketing over combined min/max so neither dist
falls outside; epsilon-clamping for empty buckets so log doesn't
blow up. Per-bucket breakdown for drilldown.
- Pairs with the existing ComputeScorerDrift: scorer drift is
categorical, distribution drift is continuous. Different shapes,
same package.
- 7 new tests covering identical-is-stable, hard-shift-is-major,
moderate-detected-not-stable, empty-inputs-safe, all-identical-
safe, bucket-counts-conserved, num-buckets-clamping.
OPEN #4 — Ops nice-to-haves (PARTIAL — wall-clock done, others
deferred):
- (a) Real-time wall-clock for stress harness: per-phase elapsed
time logged to stdout as it runs (`[stress] phase NAME starting
(T+12.3s)` + `[stress] phase NAME done — 8.5s (T+20.8s)`).
Output.PhaseTimings + Output.TotalElapsedMs in JSON.
- (b) chatd fixture-mode S3 mock + (c) liberal-paraphrase
calibration: not actioned — no fired trigger, would be
speculative. Documented as deferred-until-need rather than
ignored. Per the project's discipline ("don't add features
beyond what the task requires").
OPEN list now empty / steady-state. Future items will land as
production triggers fire.
Build + vet + tests green; 18 new tests across the 4 closures.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
PRD's 5-loop substrate names "drift" as loop 5: quantify when
historical decisions stop matching current reality. Distinct from
the rating+distillation loop because drift is MEASUREMENT, not
LEARNING. The learning loop says "this match worked, remember it";
the drift loop says "this 4-month-old playbook entry — does it
still match what the substrate would surface today?"
First-shipped drift shape: SCORER drift. When the deterministic
scorer's ScorerVersion bumps, historical ScoredRuns may no longer
match what the current scorer produces on the same EvidenceRecord.
internal/drift/drift.go:
- ScorerDriftInput — (EvidenceRecord, persisted_category) pair
- ScorerDriftEntry — one mismatch with current reasons attached
- CategoryShift — (from, to, count) cell in the shift matrix
- ScorerDriftReport — summary + sorted shift matrix + optional entries
- ComputeScorerDrift(inputs, includeEntries) — pure function;
re-runs ScoreRecord over each input and reports mismatches
Why this matters: without a drift quantifier, a scorer-rule change
silently invalidates the historical training data feeding the
learning loop. With drift quantification, a rule change surfaces
a concrete number ("847 of 4701 historical ScoredRuns now
disagree") that triggers a re-score-and-retrain cycle rather than
letting the substrate quietly rot.
Tests (6/6 PASS):
- No-drift: all 3 inputs match → 100% matched
- Shift detected: 5 inputs, 3 drift cases, drift_rate=0.6,
shift matrix shows accepted→partially_accepted x3
- Multiple shifts sorted by count desc
- includeEntries=false skips the per-mismatch list
- Empty input → all-zero report (no division-by-zero)
- ScorerVersion stamped on every report
Future drift shapes (deferred to follow-ups, named in package doc):
- PLAYBOOK drift: re-run playbook queries through current
matrix-search; recorded answer not in top-K = drift
- EMBEDDING drift: KS-test on vector distribution at T1 vs T2
- AUDIT BASELINE drift: matches Rust audit_baselines.jsonl
longitudinal signal
Pure compute. Materialization layer (read scored-runs jsonl + their
matching evidence jsonl + feed into ComputeScorerDrift) lands with
the distillation materialization commit.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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