Surfaced during the 2026-05-02 deploy + reality wave: the persistent
Go stack runs without LANGFUSE_URL/PUBLIC_KEY/SECRET_KEY env, so
shared.langfuseMiddleware operates as a passthrough — never minting
a trace id, never stashing it on the request context. Result:
session_id was empty on every JSONL row, breaking correlation across
the longitudinal log + replay_runs.jsonl + future Langfuse traces.
The fix: validatord falls back to a locally-generated time-ordered
hex id when both the X-Lakehouse-Trace-Id header AND the middleware
context are empty. Same shape Langfuse accepts, so a future deploy
that turns Langfuse on doesn't break correlation — already-emitted
session_ids stay valid as Langfuse trace ids.
Verified post-deploy by driving 9 /v1/iterate sessions through the
persistent stack at :4110:
- 6 accepted on iter 0 (qwen2.5:latest first-shot 75%)
- 2 max_iter_exhausted (no_json on prose-y prompts)
- 1 infra_error (chatd cold-start probe timed out at 5s)
Latest row's session_id: "18abbabdc2306a83-c2306aa9" (was: "")
Probe re-runs (validator_parity, session_log_parity) included as
post-deploy artifacts; both 6/6 + 4/4 with the freshly-restarted
persistent gateway+validatord binaries.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Companion to lakehouse commit 57bde63 (Rust gateway gains
trace-id propagation + coordinator session JSONL). The
cross-runtime parity probe is the regression gate that prevents
silent schema drift between the two runtimes.
scripts/cutover/parity/session_log_parity.sh:
- 4 fixtures (accepted_grounded, max_iter_exhausted, infra_error,
unicode_in_prompt) feed identical input to both helpers
- jq -e validity gate + non-trivial-equal guard prevents the
"both sides fail identically → spurious match" failure mode
(caught one IFS='||' bug during initial authoring — recorded
in the script comment)
- normalize() strips timestamp + daemon (legitimate per-producer
differences); everything else must be byte-equal
- Result: 4/4 fixtures match, including unicode
scripts/cutover/parity/session_log_helper/main.go:
- Tiny stdin/stdout Go helper that round-trips a fixture
through validator.SessionRecord serde
- Counterpart to crates/gateway/src/bin/parity_session_log.rs
docs/ARCHITECTURE_COMPARISON.md decisions tracker:
- "Rust observability parity" row added (DONE 2026-05-02)
- Cross-runtime probe documented as reusable gate
STATE_OF_PLAY refreshed.
Both observability pieces (trace-id propagation, session JSONL)
now exist on both runtimes. Operators who point Rust gateway and
Go validatord at the same session-log path get a unified
longitudinal stream queryable via DuckDB.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Closes the 2026-05-02 parity finding: validator_parity probe found
5/6 body shapes diverging because Go emitted {"Kind":"...","Field":"...","Reason":"..."}
while Rust emits the externally-tagged-enum {"Schema":{"field":"...","reason":"..."}}.
A caller parsing the error envelope would break silently in cutover.
## Changes
internal/validator/types.go:
- Custom MarshalJSON emits the Rust shape:
Schema: {"Schema": {"field":"x","reason":"y"}}
Completeness: {"Completeness":{"reason":"y"}}
Consistency: {"Consistency": {"reason":"y"}}
Policy: {"Policy": {"reason":"y"}}
- Custom UnmarshalJSON accepts BOTH the new Rust shape AND the legacy
flat shape (migration safety for any persisted error rows).
- Unknown variants (e.g. a future Rust addition Go hasn't learned)
surface as an Unmarshal error, not a silent default.
internal/validator/types_test.go:
- 4 pinning tests anchor the wire format. Failing them = wire-format
drift; the parity probe is the secondary line of defense.
scripts/validatord_smoke.sh:
- Updated probes to read the new variant-name shape (jq keys[0],
.Schema.field) instead of legacy .Kind/.Field.
## Verification
- internal/validator unit tests: PASS (4 new + all existing).
- cmd/validatord HTTP tests: PASS (UnmarshalJSON falls through to flat
shape so existing tests reading ValidationError still work).
- validatord_smoke.sh: 5/5 PASS through gateway :3110.
- validator parity probe re-run: **6/6 match** (was 1/6).
## Pattern
Per architecture_comparison's "use the dual-implementation as a
measurement instrument" thesis: a parity probe surfaced this gap;
50 LOC of MarshalJSON closed it; 4 pinning tests prevent regression;
the probe is the longitudinal gate. Cutover-friendly direction (Go
matches Rust) chosen because Rust is the existing production
contract.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Two new cross-runtime parity probes joining the validator probe from
the gauntlet wave. Pattern: feed identical input through Rust and Go;
diff outputs. Each probe surfaced a different signal.
## Materializer parity probe
scripts/cutover/parity/materializer_parity.sh runs Bun + Go
materializer against an identical synthetic data/_kb/ root, diffs the
resulting evidence/ JSONL byte-equivalent (modulo provenance.recorded_at).
**First run: 0/2 match.** Real finding: Go's Provenance.LineOffset
had `json:"line_offset,omitempty"` which strips the field when value
is 0. Line offset 0 is the FIRST ROW of every source file — a real
semantic value, not absent. Bun side always emits it.
Fix: drop `omitempty` on Provenance.LineOffset. Updated comment
explaining why.
**Re-run: 2/2 match.** On-wire JSON parity holds.
## extract_json parity probe
scripts/cutover/parity/extract_json_parity.sh feeds 12 fixture
strings through both runtimes' extract_json:
- fenced ```json``` blocks
- unfenced ``` blocks
- bare braces with prose around
- first-balanced-of-many
- nested objects
- unicode in string values
- escaped quotes
- empty object
- top-level array (both return first inner object)
- no JSON
- depth-balanced but invalid syntax
- trailing garbage
Substrate gate: cargo test -p gateway extract_json PASS before probe.
**Result: 12/12 match.** Algorithms genuinely equivalent.
## scripts/cutover/parity/extract_json_helper/main.go
Tiny Go binary that reads stdin, calls validator.ExtractJSON, prints
{matched, value} JSON. Counterpart to the Rust parity_extract_json
binary in golangLAKEHOUSE's sibling lakehouse repo (separate commit).
## Pattern crystallized
Every cross-runtime port should land with a parity probe. Three
probes now exist:
- validator (5/6 wire-format gap captured 2026-05-02)
- materializer (caught + fixed real bug 2026-05-02)
- extract_json (12/12 match 2026-05-02)
The instrument is reusable — each new shared HTTP/CLI surface gets
a probe row added.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Production-readiness gauntlet exploiting the dual Rust/Go
implementation as a measurement instrument.
## Phase 1 — Full smoke chain
21/21 PASS in ~60s. Substrate intact across the full service surface.
## Phase 2 — Per-component scrum (token-volume fix)
Prior wave (165KB diff): Kimi 62 tokens out, Qwen 297 → no useful
analysis. This wave splits today's commits into 4 focused bundles
(36-71KB each):
c1 validatord (46KB) → 0 convergent / 11 distinct
c2 vectord substrate (36KB) → 0 convergent / 10 distinct
c3 materializer (71KB) → 0 convergent / 6 distinct (Opus emitted
a BLOCK then self-retracted in same response)
c4 replay (45KB) → 0 convergent / 10 distinct
Reviewer engagement vs prior wave: Kimi went 62 → ~250 tokens out
once bundles dropped below 60KB.
scripts/scrum_review.sh hardening:
* Diff-size guard (warn >60KB, hard-fail >100KB,
SCRUM_FORCE_OVERSIZE=1 override)
* Tightened prompt — file path must appear EXACTLY as in diff
so post-processor can grep WHERE: lines reliably
* Auto-tally step dedupes by (reviewer, location); convergence
counts distinct lineages (closes the prior `opus+opus+opus`
false-convergence bug)
## Phase 3 — Cross-runtime validator parity probe (the headline finding)
scripts/cutover/parity/validator_parity.sh sends 6 identical
/v1/validate cases to Rust :3100 AND Go :4110, compares status+body.
Result: **6/6 status codes match · 5/6 body shapes diverge.**
Rust returns serde-tagged enum: {"Schema":{"field":"x","reason":"y"}}
Go returns flat exported-fields: {"Kind":"schema","Field":"x","Reason":"y"}
Both round-trip inside their own runtime; a caller swapping one for
the other would break parsing silently. Captured as new _open_ row
in docs/ARCHITECTURE_COMPARISON.md decisions tracker.
This is the "use the dual-implementation as a measurement instrument"
return — single-repo scrums can't catch this class of cross-runtime
drift.
## Phase 4 — Production assessment
ship-with-known-gap. Validator wire-format gap is documented, not
regressed. ~50 LOC future fix on Go side (custom MarshalJSON on
ValidationError to match Rust's serde shape).
Persistent stack config (/tmp/lakehouse-persistent.toml) gains
validatord on :3221 + persistent-validatord binary so operators
bringing up the persistent stack get the new daemon automatically.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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