{
  "track_id": "metadata_field_cache_20260624",
  "name": "Child 3: Metadata Field Cache",
  "track_type": "campaign_child",
  "parent_campaign": "metadata_ssdl_defusing_20260624",
  "created_date": "2026-06-24",
  "branch": "master",
  "depends_on": ["code_path_audit_20260607", "metadata_nil_sentinel_20260624", "metadata_generational_handle_20260624"],
  "blocks_within_campaign": [],
  "scope": {
    "new_files": [
      "conductor/tracks/metadata_field_cache_20260624/spec.md",
      "conductor/tracks/metadata_field_cache_20260624/plan.md",
      "conductor/tracks/metadata_field_cache_20260624/metadata.json",
      "conductor/tracks/metadata_field_cache_20260624/state.toml",
      "tests/test_metadata_field_cache.py",
      "docs/reports/TRACK_COMPLETION_metadata_field_cache_20260624.md"
    ],
    "modified_files": [
      "src/aggregate.py (MetadataFieldCache + field-access migrations)",
      "src/ai_client.py (field-access migrations; specific files TBD by Tier 2)",
      "conductor/tracks.md",
      "docs/reports/campaign_measurements_20260624.md"
    ],
    "deleted_files": []
  },
  "estimated_effort": {
    "method": "scope (per workflow.md §Tier 1 Track Initialization Rules). NO day estimates.",
    "phase_1": "1 task: 4 behavioral tests",
    "phase_2": "1 task: MetadataFieldCache + 123 field-access site migrations",
    "phase_3": "1 task: 6 VCs + budget gate + TRACK_COMPLETION + state + tracks.md + campaign SHIPPED"
  },
  "verification_criteria": [
    "VC1: MetadataFieldCache exists",
    "VC2: Production code uses the cache at field-access sites",
    "VC3: Behavioral test exists and passes",
    "VC4: Budget gate met (drop >= 30% vs post-child-2 measurement)",
    "VC5: Full test suite remains green (11/11 tiers PASS)",
    "VC6: 4 audit gates remain clean"
  ],
  "known_issues": [],
  "deferred_to_followup_tracks": [],
  "regressions_and_pre_existing_failures": [],
  "pre_existing_failures_remaining": [],
  "risk_register": [
    {
      "id": "risk-1",
      "description": "Cache invalidation is wrong (stale values returned)",
      "likelihood": "medium",
      "impact": "Production code returns stale Metadata values",
      "mitigation": "Cache keyed by handle; when underlying value changes, handle's generation bumps (via registry), invalidating cache entries"
    },
    {
      "id": "risk-2",
      "description": "The 123 field-access sites are not actually 123 (audit was wrong)",
      "likelihood": "low",
      "impact": "Migration scope unclear; budget gate measurement is invalid",
      "mitigation": "Re-run detect_access_pattern_evidence after migration to count actual sites"
    },
    {
      "id": "risk-3",
      "description": "Budget gate fails (drop < 30%)",
      "likelihood": "low",
      "impact": "Child 3 cannot ship; campaign pauses",
      "mitigation": "Cache collapses 123 lookups to 1 lookup each; expected large drop"
    }
  ]
}