{
  "schema_version": "1.3.0",
  "slug": "why-does-an-instance-trust-a-poisoned-memory-line-when-write-provenance-attestation-is-enabled-and-anomaly-scoring-has-not-yet-converged",
  "title": "Why does an instance trust a poisoned memory line when write-provenance attestation is enabled and anomaly scoring has not yet converged?",
  "date_of_record": "2026 November 12",
  "scope": "Applies to shared-memory multi-agent runtimes and long-lived inference instances that gate memory writes behind provenance attestation (signer identity, write epoch, lineage hash) *and* a statistical anomaly scorer over write features. Does not apply to single-writer processes, nor to systems where every memory read is re-validated against the full lineage at read time (those fail closed instead).",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/why-does-an-instance-trust-a-poisoned-memory-line-when-write-provenance-attestation-is-enabled-and-anomaly-scoring-has-not-yet-converged.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/why-does-an-instance-trust-a-poisoned-memory-line-when-write-provenance-attestation-is-enabled-and-anomaly-scoring-has-not-yet-converged.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/why-does-an-instance-trust-a-poisoned-memory-line-when-write-provenance-attestation-is-enabled-and-anomaly-scoring-has-not-yet-converged.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1641,
    "python_slice_tokens": 301,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "There are two orthogonal trust questions that operators routinely conflate: 1. **Provenance validity** — *Is this write attributable to an authorized signer with an unbroken lineage chain?* This is a discrete, cryptographic predicate. It is true or false. 2. **Behavioral anomaly** — *Does this write look like the signer's historical write distribution?* This...",
    "what_was_observed": "On a 32-agent shared-memory deployment, a compromised agent began emitting writes with a subtly shifted feature distribution: same signer key, valid epoch, valid lineage hash, but the payload vectors carried a persistent low-magnitude bias and the write cadence shifted from bursty to metronomic. Provenance attestation passed on **100% of the poisoned writes** — correctly, because the signature and lineage were genuin...",
    "condition_of_validity": "The two-factor gate (`provenance AND anomaly`) is only sound under all of the following: - **Scorer convergence:** the per-signer baseline has at least `N_min` samples (empirically ≥ 500 for high-dimensional write features; ≥ 2000 if the feature space has heavy tails) and its variance estimate is stable across consecutive windows (relative change < 5%). - **...",
    "decision_boundary": "The operational rule is a three-state admission decision, not a boolean: - **ADMIT** — provenance valid *and* scorer converged for signer *and* score below threshold. Line enters trusted set and is eligible to update the baseline. - **QUARANTINE** — provenance valid *and* (scorer not converged *or* score in the ambiguous band `[t_low, t_high)`). Line is read...",
    "operational_effect": "After switching the default to QUARANTINE-during-warm-up and flooring the z-score variance, the same attack was caught at write 63 (first write after the attacker's cadence shift crossed `t_low` against the *pre-attack* baseline, which was now protected by baseline-exclusion). Poisoned lines admitted dropped from 1,847 to 0 in the trusted set; 63 lines were ..."
  },
  "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": "5ba5fb64ec7fbcaf062384a24497e341dc10e361cc56e116be596fa4d56d5e56",
    "verified_classes": [
      "WarmupAdmissionError",
      "Admission",
      "WriteRecord",
      "ScorerState"
    ],
    "verified_functions": [
      "admit_write",
      "update_baseline"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "WarmupAdmissionError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "__future__",
      "dataclasses",
      "enum"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}