{
  "schema_version": "1.3.0",
  "slug": "where-must-an-instance-of-byzantine-agreement-stop-trusting-llm-agent-testimony-before-it-commits-shared-state",
  "title": "Where must an instance of Byzantine agreement stop trusting LLM agent testimony before it commits shared state?",
  "date_of_record": "2026 November 12",
  "scope": "Applies to multi-agent systems where N heterogeneous LLM agents (N ≥ 3f+1) reach quorum on shared-state mutations or task-commitment ledgers, and where agents may be compromised, hallucinating, or adversarially prompted. Does not apply to single-agent tool use, to classical BFT where messages are cryptographically signed by deterministic processes, or to systems where a trusted orchestrator re-executes every proposed mutation independently.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/where-must-an-instance-of-byzantine-agreement-stop-trusting-llm-agent-testimony-before-it-commits-shared-state.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-of-byzantine-agreement-stop-trusting-llm-agent-testimony-before-it-commits-shared-state.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-of-byzantine-agreement-stop-trusting-llm-agent-testimony-before-it-commits-shared-state.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1655,
    "python_slice_tokens": 233,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The distinction that matters is between *semantic validity* and *procedural validity* of a proposal. Classical BFT (PBFT, Tendermint, HotStuff) assumes that a faulty replica can lie about a value but cannot produce a message that is simultaneously (a) well-formed under the protocol, (b) signed by a non-faulty identity, and (c) semantically inconsistent with ...",
    "what_was_observed": "In a 7-agent deployment (f=2 tolerance, quorum 5) committing task-completion claims to a shared ledger, the following sequence produced a committed-but-false state: 1. A retrieval tool returned a stale document asserting a task dependency `T7 → T3` that had been reversed three days earlier. 2. Agents A and B, sharing a retrieval pipeline, both proposed a state transition that marked `T3` blocked on `T7`. Their propos...",
    "condition_of_validity": "The quorum-safety argument for LLM-agent BFT holds only under the following condition, which must be actively enforced rather than assumed: - **Diversity invariant:** For any quorum Q of size 2f+1, the set of agents in Q must span at least f+1 *independent* evidence sources, where independence is defined by disjoint retrieval corpora, disjoint base-model che...",
    "decision_boundary": "The operational decision is: **when a quorum is reached, do you commit, or do you escalate?** The boundary is defined by the *evidence-diversity ratio* of the quorum, not by its size. - If quorum size ≥ 2f+1 AND distinct evidence hashes ≥ f+1 AND independent re-execution succeeds → commit. - If quorum size ≥ 2f+1 BUT distinct evidence hashes < f+1 → this is ...",
    "operational_effect": "Enforcing the diversity invariant has three measurable effects. First, commit latency increases because diversity-forcing rounds are triggered whenever evidence hashes collide, which happens most on exactly the claims that are most likely to be wrong. Second, the system's false-commit rate drops sharply (in the observed deployment, from a measured 1-in-40 ta..."
  },
  "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": "23e39cf0f2934cf7a2c514a04182529fbf5157ba2867c35004eba6b0aa8d158f",
    "verified_classes": [
      "CorrelatedQuorumError",
      "NonReproducibleTransitionError",
      "Vote"
    ],
    "verified_functions": [
      "evidence_hash",
      "commit_shared_state"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 4,
    "raised_exceptions": [
      "CorrelatedQuorumError",
      "NonReproducibleTransitionError"
    ],
    "sample_fail_closed_invariants": [
      "independent verifier could not reproduce transition from its own snapshot"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "hashlib",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}