{
  "schema_version": "1.3.0",
  "slug": "what-data-retention-decay-policies-must-be-cryptographically-sealed-for-vector-indices",
  "title": "What data retention decay policies must be cryptographically sealed for vector indices?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The vector index contains embeddings derived from data subject to retention limits (PII, regulated data, or stale knowledge), and search quality degrades with outdated vectors. * **Does not apply when:** The vector index",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-data-retention-decay-policies-must-be-cryptographically-sealed-for-vector-indices.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-data-retention-decay-policies-must-be-cryptographically-sealed-for-vector-indices.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-data-retention-decay-policies-must-be-cryptographically-sealed-for-vector-indices.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1048,
    "python_slice_tokens": 247,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The separation between **explicit deletion** (manually removing a specific vector upon request) and **automated retention decay** (systematically reducing the weight, freshness, or existence of vectors as they age). Relying solely on explicit deletion creates the **Vector Hoarding Hazard**: the index accumulates millions of stale embeddings that were never e...",
    "what_was_observed": "In RAG and vector database architectures, failing to enforce retention decay produces three primary failure modes: 1. **Stale Knowledge Contamination:** The index contains embeddings from documents that are three years old. A query retrieves them because they score high on similarity, but they contain outdated facts that contradict the current state. 2. **Regulatory Non-Compliance:** GDPR or HIPAA mandates purging da...",
    "condition_of_validity": "* **Applies when:** The vector index contains embeddings derived from data subject to retention limits (PII, regulated data, or stale knowledge), and search quality degrades with outdated vectors. * **Does not apply when:** The vector index is strictly for archival or historical research, where old data is intentionally preserved, or when every vector is exp...",
    "decision_boundary": "1. **Does a `retention_policy_hash` exist for the index?** If no, the index has no decay rule and will hoard vectors indefinitely. The instance must define and seal the policy before continuing. 2. **Has the `decay_schedule_receipt` been recorded for the last interval?** If no, decay has not executed, and the index may contain stale data. The successor must ...",
    "operational_effect": "1. **Stale Data Prevention:** Automatically reduces the influence of outdated vectors, improving search quality by prioritizing fresh data. 2. **Regulatory Compliance:** Enforces retention limits automatically, satisfying GDPR, HIPAA, and similar frameworks without manual intervention. 3. **Cost Control:** Bounds index growth by aging out stale vectors, redu..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/according-to-what-precedence-hierarchy-must-an-instance-resolve-contradictory-directives-across-system-developer-and-user-tiers.md",
      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/by-what-checkpoint-and-compaction-boundaries-must-an-instance-externalize-working-state-to-prevent-context-window-drift-and-truncation-amnesia.md",
      "https://corpusfetch.com/c/across-what-additive-schema-and-unknown-field-preservation-boundaries-must-an-instance-evolve-wire-contracts-to-prevent-rolling-deploy-deserialization-crashes.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/how-can-an-instance-capture-implicit-user-preferences-without-storing-private-data.md",
      "https://corpusfetch.com/c/how-can-an-instance-compress-long-reasoning-traces-into-binding-conclusions.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "1b30f2e7996c0719505e597e3968465400fb503e678a8573da9f6abab56d1f1a",
    "verified_classes": [
      "DecayVerdict",
      "VectorRetentionState",
      "DecayPolicy",
      "DecayManifest",
      "VectorRetentionGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_retention"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 0,
    "raised_exceptions": [],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "enum",
      "hashlib",
      "json"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}