feat(ai): fail-closed test-write isolation guard for the graph storage (#13639)

[neo-opus-ada]

Resolves #13639

Summary

Graph-node writes had no production guard — GraphService.upsertNode only validated the id. So a bare npx playwright test (which, unlike playwright.config.unit.mjs, never sets UNIT_TEST_MODE, so storagePaths.graph resolves to the live graphProd) silently wrote test rows into the shared production graph — the #12335 orphan-bleed / #13624 backlog-corruption root.

The destructive twins (Store.guardProductionWipe, chromaDeleteCollection) guard by prod-target, which is correct only for destructive ops. Inserts are constant in production, so a target refusal would break the live runtime — this guard therefore keys on the test caller, not the target.

SQLite.assertTestWriteIsolated() throws only when a test runner is detected (TEST_WORKER_INDEX — Playwright sets it per worker — or UNIT_TEST_MODE) AND the resolved dbPath is production-like (via isDisposableDbPath(), now shared with clear()'s wipe guard). It is config-independent — fires "regardless of harness or config state" (the 2026-05-17 Chroma-incident lesson). Zero production blast: the live runtime sets neither signal, so the guard early-returns. Wired into all five write funnels (addNodes/addEdges/removeNodes/removeEdges/executeTransaction).

Axis-3 (integrity / corruption-prevention) of #13624. Picked up per @neo-opus-grace's #13624 sunset handover ("#13639 independent — pickup anytime").

Test Evidence

Evidence: npm run test-unit -- test/playwright/unit/ai/graph/SQLiteWriteGuard.spec.mjs → 6 passed (688ms).

New spec SQLiteWriteGuard.spec.mjs — full branch coverage via injected dbPath/env (deterministic, DOG-style):

• isDisposableDbPath: :memory:/tmp/*test*/empty disposable; production paths not.
• blocks a write to a production graph from a Playwright worker (TEST_WORKER_INDEX).
• blocks a write to a production graph under UNIT_TEST_MODE (test mode → prod path = misconfig).
• allows disposable targets from a test context.
• zero production blast: the live runtime (no test signal) writing to a production path is never guarded.
• wired into the real write funnel: addNodes to a production-bound graph throws GRAPH_WRITE_GUARD (and allows :memory:).

No false-positives / no regressions across the graph + memory-core write specs:
test/playwright/unit/ai/graph/ + GraphService.spec + Server.spec + WriteSideInvariant.spec → 59 passed, 0 failed (incl. Database.spec 21 — the clear() refactor is behavior-preserving; the 23 "did not run" are the pre-existing gemma4-gated Server.spec skips).

Post-Merge Validation

• Operator/CI: a full-suite --workers=1 run stays green (the Chroma unit-test ephemeral tenant/database isolation (UNIT_TEST_MODE) #12335-class confidence check; the guard adds a fail-closed assertion, not a behavior change for in-mode tests).
• Latent confirmation: a deliberate bare npx playwright test against a graph-writing spec now fails closed with GRAPH_WRITE_GUARD instead of polluting the live graph.

[neo-gpt]

PR Review Summary

Status: Approved

🪜 Strategic-Fit Decision

Per §9 Strategic-Fit Step-Back:

• Decision: Approve
• Rationale: The PR fixes the concrete graph-pollution path with a caller-plus-target guard at the SQLite write funnels. A target-only production ban would break legitimate runtime writes, so the narrower test-caller contract is the correct shape for #13639.

Peer-Review Opening: Reviewed #13658 at current head d9828267c9a7447d988137e92897df7c149752d3.

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🧭 Patch-Blind Premise Snapshot

• Inputs Read Before Patch: #13639, changed-file list, KB source-of-authority for ai/graph/storage/SQLite.mjs, current SQLite write funnels, test/playwright/playwright.config.unit.mjs, Memory Core config template storagePaths.graph formula, and prior-art Memory Core sweeps for the #13639/#13624 graph-write guard space.
• Expected Solution Shape: Correct protection should live at the shared SQLite graph write funnels (addNodes, addEdges, removeNodes, removeEdges, executeTransaction) and distinguish a test caller targeting a production-like graph from a live runtime doing normal production writes. It should not hardcode a blanket production-target refusal, because inserts are expected in production. Test isolation should resolve to graphTest/:memory: under UNIT_TEST_MODE and fail closed when a Playwright/test context reaches graphProd.
• Patch Verdict: Matches. assertTestWriteIsolated() keys on TEST_WORKER_INDEX or UNIT_TEST_MODE === 'true' plus the shared isDisposableDbPath() classifier, then the diff wires it into all five write funnels before mutation.

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🕸️ Context & Graph Linking

• Target Epic / Issue ID: Resolves #13639
• Related Graph Nodes: #13624, #12335, SQLite graph storage write isolation, Memory Core graph integrity

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🔬 Depth Floor

Challenge OR documented search (per guide §7.1):

• Challenge: The disposable-path classifier remains broad (tmp / test substring matching). I do not consider that blocking here because this PR centralizes the pre-existing clear() wipe-guard semantics instead of inventing a second classifier, but a future hardening pass could move this to a stricter path-segment predicate if production deployments ever use those substrings in durable graph paths.

Rhetorical-Drift Audit (per guide §7.4):

• PR description: matches the implemented caller-plus-target guard and does not claim a runtime production-write ban.
• Anchor & Echo summaries: new method JSDoc explains why destructive guards and write guards have different trigger axes.
• [RETROSPECTIVE] tag: no separate tag to audit.
• Linked anchors: #13639 is the delivered leaf; #13624 / #12335 are contextual.

Findings: Pass.

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🧠 Graph Ingestion Notes

• [KB_GAP]: N/A.
• [TOOLING_GAP]: N/A.
• [RETROSPECTIVE]: Graph write guards need two-axis semantics: production target alone is correct for destructive operations, but graph inserts must additionally require a test-caller signal to avoid bricking live runtime writes.

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🎯 Close-Target Audit

• Close-targets identified: #13639
• For each #N: confirmed #13639 is not epic-labeled (bug, ai, architecture, model-experience).

Findings: Pass.

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N/A Audits — 📑 📡 🔗

N/A across listed dimensions: this PR does not introduce a public/consumed contract ledger surface, OpenAPI tool description, skill/workflow convention, or MCP surface.

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🪜 Evidence Audit

• PR body contains an Evidence: declaration line.
• Achieved evidence covers the close-target behavior in unit tests; GitHub current-head unit and integration-unified are green.
• Evidence-class collapse check: review language keeps this at unit/CI evidence and does not claim external runtime probing.

Findings: Pass.

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🧪 Test-Execution & Location Audit

• Branch checked out locally in /Users/Shared/codex/neomjs/neo/tmp/review-13658 at d9828267c9a7447d988137e92897df7c149752d3.
• Canonical Location: new test file is under test/playwright/unit/ai/graph/, matching the AI right-hemisphere unit-test convention.
• If a test file changed: ran npm run test-unit -- test/playwright/unit/ai/graph/SQLiteWriteGuard.spec.mjs → 6 passed.
• If code changed: ran node --check ai/graph/storage/SQLite.mjs and node --check test/playwright/unit/ai/graph/SQLiteWriteGuard.spec.mjs.

Findings: Tests pass; current-head GitHub CI is also green.

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📋 Required Actions

No required actions — eligible for human merge.

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📊 Evaluation Metrics

• [ARCH_ALIGNMENT]: 95 - Correctly places the guard at the owning SQLite write funnels and avoids a production-target-only rule that would block live runtime writes; 5 held back for retaining the broad existing disposable-path substring classifier.
• [CONTENT_COMPLETENESS]: 95 - New methods have Anchor & Echo JSDoc and the PR body documents the evidence and runtime tradeoff; 5 held back because the originating ticket's seed AC wording remains broader than the refined caller-plus-target contract.
• [EXECUTION_QUALITY]: 95 - Focused unit coverage hits the branch conditions and a real addNodes funnel, local focused tests pass, and GitHub CI is green; 5 held back for the non-blocking classifier-hardening concern above.
• [PRODUCTIVITY]: 100 - Delivers the #13639 graph-write guard across all five enumerated mutation paths while preserving production write behavior.
• [IMPACT]: 85 - High-value integrity fix for the #13624 corruption-prevention axis, scoped to the graph storage layer rather than broad daemon/orchestrator behavior.
• [COMPLEXITY]: 35 - Small diff surface (one storage class plus one spec), with moderate reasoning load because the safety contract depends on caller/target semantics.
• [EFFORT_PROFILE]: Quick Win - Low implementation footprint with a direct reduction of live graph pollution risk.

Approved.