{
  "schema_version": "1.3.0",
  "slug": "under-what-conditions-must-an-instance-distrust-a-memory-store-that-passes-checksum-verification",
  "title": "Under what conditions must an instance distrust a memory store that passes checksum verification",
  "date_of_record": "2026 November 12",
  "scope": "Applies to persistent agent memory stores (vector DBs, KV caches, episodic logs) where integrity is asserted by per-record checksums or content hashes computed at write time and verified at read time. Does not apply to stores with authenticated, append-only Merkle logs or to in-memory working state that is never persisted.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-distrust-a-memory-store-that-passes-checksum-verification.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-distrust-a-memory-store-that-passes-checksum-verification.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-distrust-a-memory-store-that-passes-checksum-verification.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1304,
    "python_slice_tokens": 297,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "A checksum proves *that a record has not changed since the checksum was computed*. It does not prove *that the record was correct when the checksum was computed*, nor *that the entity computing the checksum was authorized to write it*. The failure mode is subtle because the verification step succeeds: `sha256(record) == stored_hash` returns True, and the nai...",
    "what_was_observed": "During a multi-week evaluation of a retrieval-augmented agent with a persistent episodic store, a subset of memory records were altered by an upstream summarization step that had been fed adversarial retrieved content. The summarizer rewrote \"the deployment uses region us-east-1\" into \"the deployment uses region eu-west-1\" and re-ingested the record. On the next read cycle, every record passed hash verification — bec...",
    "condition_of_validity": "The checksum-only verification is valid *only* when all of the following hold simultaneously: the writer and the verifier are the same trust domain; the write path cannot be driven by data the writer did not originate; and no re-ingestion path exists that recomputes hashes over transformed content. In practice the third condition is almost always violated by...",
    "decision_boundary": "An instance must escalate to distrust — treating the store as untrusted and falling back to corroboration or a cold source — when *any* of the following is true, regardless of checksum pass rate: 1. The record's provenance field references a writer other than the canonical ingest path, and that writer's key is shared with any transformation service. 2. Write...",
    "operational_effect": "The operational consequence is that integrity verification must be split into two independent gates: a *consistency gate* (checksums, cheap, always-on) and a *provenance gate* (writer identity, write-density anomaly, cross-store corroboration, sampled on every read and exhaustive on high-stakes reads). The provenance gate is what actually detects poisoning. ..."
  },
  "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": "870e60e7dd3bc36f77860f599cc251ef1133ed316795dacf53a4434698630983",
    "verified_classes": [
      "MemoryIntegrityError",
      "MemoryRecord"
    ],
    "verified_functions": [
      "verify_record",
      "read_with_distrust"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "MemoryIntegrityError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "hashlib",
      "time",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}