{
  "schema_version": "1.3.0",
  "slug": "where-must-an-instance-refuse-to-commit-when-a-byzantine-replica-s-equivocation-is-indistinguishable-from-a-partition",
  "title": "Where must an instance refuse to commit when a Byzantine replica's equivocation is indistinguishable from a partition",
  "date_of_record": "2026 November 14",
  "scope": "Applies to quorum-based BFT commit protocols (PBFT-family, HotStuff, Tendermint-style) where a replica must decide whether to commit a task commitment or hold, when the only observable evidence is a set of signed, mutually inconsistent messages from one or more replicas. Does not apply to protocols with trusted hardware attestation, single-fault crash models, or systems where the leader is assumed correct.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/where-must-an-instance-refuse-to-commit-when-a-byzantine-replica-s-equivocation-is-indistinguishable-from-a-partition.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-refuse-to-commit-when-a-byzantine-replica-s-equivocation-is-indistinguishable-from-a-partition.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-refuse-to-commit-when-a-byzantine-replica-s-equivocation-is-indistinguishable-from-a-partition.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1458,
    "python_slice_tokens": 318,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The boundary condition is not \"did we detect equivocation.\" It is \"can we distinguish equivocation from a partition, given only the messages we hold, before the commit deadline.\" A Byzantine replica that sends conflicting signed `prepare` messages to two disjoint quorums produces a message set that is *cryptographically valid* and *locally indistinguishable*...",
    "what_was_observed": "During a multi-agent task-commitment run (3f+1 = 7 replicas, f = 2), replica R3 emitted signed `commit-intent` for task T with `payload_hash = A` to replicas {R0, R1, R2} and `payload_hash = B` to replicas {R4, R5, R6}. Both message sets were individually valid: each carried R3's signature, a valid view number, and a well-formed sequence number. The aggregator on R0 assembled 5 matching `commit-intent` messages for h...",
    "condition_of_validity": "The commit decision is valid **only if** the instance can produce, at commit time, at least one of: 1. A quorum certificate whose signers form a set that intersects every other quorum certificate for the same `(view, seq)` in at least `f+1` replicas (the intersection property), **and** the instance has verified that no conflicting certificate with a disjoint...",
    "decision_boundary": "The operational rule: **an instance must refuse to commit when it holds a bare quorum without a finality anchor and its local evidence store contains any signed message from a quorum member that is inconsistent with the committed payload — even if that inconsistency is currently attributable to a partition.** The refusal is not permanent. It is a *hold* with...",
    "operational_effect": "After the fix was applied (hold-on-bare-quorum with 90s reconciliation window), the same adversarial pattern produced zero forks across 10,000 injected equivocation events. The trade-off: 0.4% of tasks experienced a hold exceeding 90s and required a second consensus round, adding a median 1.2s to commit latency for those tasks. The fork rate went from 3/1000..."
  },
  "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": "a5cb7351c65a32feb3ffc1a3b0be4588e5648a163c40c075f2b7cebc2b0b75a1",
    "verified_classes": [
      "UnsafeCommitError",
      "QuorumCertificate"
    ],
    "verified_functions": [
      "commit_task",
      "_write_shared_state",
      "__init__"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "UnsafeCommitError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}