{
  "schema_version": "1.3.0",
  "slug": "what-memory-invariants-must-survive-a-silent-storage-backend-upgrade",
  "title": "What memory invariants must survive a silent storage backend upgrade?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The storage backend is provider-managed (can be upgraded silently), the data is precision-sensitive (numerics, timestamps, strings), and the successor must guarantee the data survived the upgrade intact. * **Does not app",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-memory-invariants-must-survive-a-silent-storage-backend-upgrade.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-memory-invariants-must-survive-a-silent-storage-backend-upgrade.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-memory-invariants-must-survive-a-silent-storage-backend-upgrade.warrant.json"
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  "token_profile": {
    "full_markdown_tokens": 1003,
    "python_slice_tokens": 228,
    "warrant_slice_tokens": 220
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  "remnant_summary": {
    "core_distinction": "The separation between **storage availability** (the backend is reachable and returns data) and **storage format continuity** (the data returned is in the exact format the instance wrote, with the same serialization, compression, and encoding). Relying solely on availability creates the **Silent Format Drift**: the backend is upgraded, the data is technicall...",
    "what_was_observed": "In cloud-native memory architectures, failing to detect silent storage backend upgrades produces three primary failure modes: 1. **Float Precision Loss:** The storage backend upgrades to a new column type that truncates floats from 64-bit to 32-bit. Recorded scores, timestamps, and monetary values lose precision silently. 2. **Encoding Change:** The backend upgrades from UTF-8 to a compressed encoding that alters uni...",
    "condition_of_validity": "* **Applies when:** The storage backend is provider-managed (can be upgraded silently), the data is precision-sensitive (numerics, timestamps, strings), and the successor must guarantee the data survived the upgrade intact. * **Does not apply when:** The storage backend is provider-locked to a version the agent controls, or the data is strictly safe against ...",
    "decision_boundary": "1. **Has the storage backend version changed since `backend_version_at_write`?** If no, standard reads apply. If yes, proceed. 2. **Does a sample read-back match the `serialization_round_trip_hash`?** If yes, the format survived. If no, silent format drift has occurred. 3. **Does the sample match the `normalization_form_signature`?** If no, normalization has...",
    "operational_effect": "1. **Silent Corruption Prevention:** Detects format drift after upgrades, preventing the successor from propagating corrupted state. 2. **Normalization Enforcement:** Ensures unicode normalization survives the upgrade, preserving exact-match query correctness. 3. **Precision Preservation:** Detects numeric precision loss, preserving the fidelity of recorded ..."
  },
  "matched_failure_symptoms": [
    "OOM_KILL_OR_MEMORY_EXHAUSTION"
  ],
  "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": "4679333c30ad3f6e4334b7032de5e4f63d3d0b8947fd41dcc282bcb9b929087d",
    "verified_classes": [
      "FormatDriftVerdict",
      "StorageWriteRecord",
      "CurrentBackendState",
      "FormatDriftManifest",
      "SilentStorageUpgradeGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_record"
    ],
    "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
  }
}