PR Review Summary

Status: Approved

🪜 Strategic-Fit Decision

Per §9 Strategic-Fit Step-Back:

• Decision: Approve
• Rationale: Clean parallel of the #11980 + #12000 trust-tier pattern, applied to the third remaining #10292 slice (frontier hydration ranking). Bounded scope (+148/-2, 2 files), Refs #10292 (not Resolves) explicitly preserves the open get_context_frontier follow-up surface and forward-only migration docs. The trust-weight formula is bounded and linear; weighted score composes cleanly with the existing graph-topology weight. CI all green at 23084f467.

Peer-Review Opening: Nice closer on the third #10292 slice — projecting sourceTrustTier into the frontier hydration and ranking by weight × trustWeight is the substrate-correct shape for trust-aware semantic surfacing. Approving.

🕸️ Context & Graph Linking

• Target Epic / Issue ID: Refs #10292 (deliberately not Resolves — durable forward-only migration docs + final rollout reconciliation remain per PR body)
• Related Graph Nodes: #11979 (summary provenance stamping), #11980 (raw-memory trust filter), #12000 (query_summaries trust filter); ai/graph/identityRoots.mjs (TRUST_TIERS + TRUST_TIER_ORDER source of authority)

🔬 Depth Floor

Documented search: I actively looked for (1) trust-weight formula bounds — verified (maxRank - rank + 1) / (maxRank + 1) lies in (0, 1] for all 8 tiers (SYSTEM=1.0 → UNCLASSIFIED=0.125); (2) backward-compat — confirmed metadata field still preserved on each semanticContext, only additive new fields (trustTier, trustWeight, weightedScore); (3) sort-order side effects — grep across ai/ test/ for sibling assertions on semanticContexts ordering found none other than the new test; (4) OpenAPI claim — confirmed /context/frontier response declares schema: type: object (generic, no breaking change for additive fields); (5) parallel pattern consistency — resolveSummaryTrustTier mirrors SummaryService.resolveSummaryTrustTier byte-for-byte (intentional reuse across services for the summary-provenance contract). No concerns.

Rhetorical-Drift Audit:

• PR description: framing matches diff (narrow frontier-ranking slice; explicit Refs not Resolves)
• JSDoc additions: precise — getFrontierTrustWeight documents the multiplier semantic + (0, 1] range; resolveSummaryTrustTier documents the SessionService stamping anchor
• No [RETROSPECTIVE] tag inflation
• Linked anchors: PR body cites #12000 + #11979 + #11980 correctly; the parallel pattern is real

Findings: Pass.

🧠 Graph Ingestion Notes

• [RETROSPECTIVE]: Linear trust-weight decay (maxRank - rank + 1) / (maxRank + 1) is the calibration choice (not the only viable shape — exponential decay would penalize low-trust contexts more aggressively). The 8-tier ladder produces concrete multipliers: SYSTEM=1.0, REPO_TRUSTED=0.875, OWNER=0.75, SELF=0.625, PEER_TRUSTED=0.5, INTERNAL_AUTHORED=0.375, EXTERNAL=0.25, UNCLASSIFIED=0.125. Linear preserves the "still returned but ranked lower" intent. Worth re-visiting if/when post-deployment empirical evidence shows the multiplier shape mis-ranks contexts.

N/A Audits — 🎯 📑 📡 🔗

N/A across listed dimensions: no close-target magic keyword (Refs #10292, not Resolves); no Contract Ledger in the parent ticket (multi-slice epic; per-slice contracts inline in PR body); OpenAPI response is generic type: object so additive response-field projection requires no schema update; no skill / convention / startup-substrate changes.

🪜 Evidence Audit

• PR body contains an Evidence: declaration line (L1 → L1 required)
• ## Post-Merge Validation section present with the remaining #10292 follow-up surface noted
• L1 evidence: 16/16 PASS focused MemoryService.TenantIsolation.spec.mjs is the right ceiling for service-method ranking behavior — pure-function deterministic; no harness / wake / restart / runtime-effect AC requiring L2+

Findings: Pass.

🔌 Wire-Format Compatibility Audit

PR adds 3 fields per semanticContext in getContextFrontier's response:

• trustTier: 'system' | ... | 'unclassified'
• trustWeight: Number (0, 1]
• weightedScore: Number

OpenAPI: get_context_frontier response is schema: type: object (generic). Additive fields are backward-compatible — existing clients ignore unknown keys.

Sort order change: semanticContexts is now sorted by (weightedScore DESC, weight DESC). Previously the array preserved the graph-topology iteration order. This IS a behavioral change visible to consumers — but no sibling test/spec asserts on the pre-fix order (grep across ai/ test/ confirmed), and the PR body documents the new ranking semantic in Deltas from ticket.

Findings: Pass — backward-compatible additive fields + behaviorally-aligned sort change.

🧪 Test-Execution & Location Audit

• PR body Test Evidence lists MemoryService.TenantIsolation.spec.mjs — 16/16 passed
• Canonical Location: new test in existing test/playwright/unit/ai/services/memory-core/MemoryService.TenantIsolation.spec.mjs
• CI verified green at 23084f467 (lint-pr-body, CodeQL, Retired Primitives, unit, integration-unified all PASS)
• Test fixture mocks GraphService.getContextFrontier + StorageRouter.getSummaryCollection at the right layer; the new test would FAIL pre-fix because the pre-fix code didn't compute weightedScore and didn't sort by it
• Spy fixture for Chroma collection mirrors the pattern established in #12000 (createSpyCollection + rows.set)
• Test assertions verify both the projection (3 new fields on each semanticContext) and the ranking (owner > external > legacy ordering)

Findings: Pass. Local re-run skipped — CI is green, test layer is at the right boundary, fixture pattern is the established one.

📋 Required Actions

No required actions — eligible for human merge.

📊 Evaluation Metrics

• [ARCH_ALIGNMENT]: 95 - Direct parallel of #11980 + #12000 trust-tier patterns. resolveSummaryTrustTier reuses the same semantic; new getFrontierTrustWeight is a clean composition. Trust-multiplier composes cleanly with the existing graph-topology weight.
• [CONTENT_COMPLETENESS]: 90 - PR body has Deltas, Test Evidence, Post-Merge Validation. 10 points off for the FAIR-band line saying [16/30 — current author count over last 30 merged] — the format is non-standard (most authors quote band classification + count). Minor.
• [EXECUTION_QUALITY]: 95 - Formula bounds verified; sort tiebreaker is the existing weight (sensible); JSDoc explains both projection and weight semantics; test covers projection + ranking.
• [PRODUCTIVITY]: 90 - Closes one more AC surface of #10292 cleanly; explicit Refs not Resolves keeps the ticket open for migration-docs follow-up.
• [IMPACT]: 75 - Frontier ranking is the highest-visibility consumer surface of the trust-tier substrate; trust-aware semantic surfacing is the substrate goal #10292 was opened for. One more slice after this closes the ticket.
• [COMPLEXITY]: 35 - Low: two files, additive change with a small new helper and a sort.
• [EFFORT_PROFILE]: Quick Win - Bounded slice leveraging the established #11980/#12000 pattern.

Approving — eligible for operator merge.