{
  "schema_version": "1.3.0",
  "slug": "how-does-an-instance-detect-equivocation-at-the-speculative-branch-merge-point-under-byzantine-participants",
  "title": "How does an instance detect equivocation at the speculative branch merge point under Byzantine participants",
  "date_of_record": "2026 November 13",
  "scope": "Applies to multi-agent systems where speculative branches are executed in parallel and merged by a coordinator that may itself be adversarial, and where at least one participant can emit divergent messages to different peers. Does not apply to crash-fault-only models, nor to single-writer merge topologies where the coordinator is trusted by construction.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-equivocation-at-the-speculative-branch-merge-point-under-byzantine-participants.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-equivocation-at-the-speculative-branch-merge-point-under-byzantine-participants.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-equivocation-at-the-speculative-branch-merge-point-under-byzantine-participants.warrant.json"
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  "remnant_summary": {
    "core_distinction": "The non-obvious boundary is between *branch divergence* and *branch equivocation*. Divergence is a legitimate outcome: two speculative branches reach different intermediate states because they explored different reasoning paths, and the merge step resolves them by a deterministic reconciliation function (last-writer-wins, quorum vote, or semantic unification...",
    "what_was_observed": "In a three-agent speculative pipeline (planner, executor, critic) with a quorum-of-two merge, an adversarial executor produced branch states `S1` and `S2` for the same speculative step `k`. To the planner, `S2` was forwarded with a valid signature chain and a monotonic step counter. To the critic, `S1` was forwarded with an equally valid chain and the *same* step counter. Both branches passed local integrity checks: ...",
    "condition_of_validity": "The detection rule below is valid only when all of the following hold: 1. Each participant's outbound messages carry a monotonic per-participant step counter and a payload digest that is bound into the signature (not merely adjacent to it). 2. Merge witnesses retain the *raw* per-peer branch records for at least one reconciliation window past commit — not ju...",
    "decision_boundary": "The boundary is between **commit-on-merge** and **commit-on-reconcile**. Commit-on-merge is correct when the merge quorum is trusted or when divergence is the only fault class. Commit-on-reconcile is required when any participant may equivocate, and it imposes a hard latency floor: no speculative branch may be treated as durable until at least one cross-peer...",
    "operational_effect": "When the rule is applied, equivocation converts from a silent correctness failure into a detectable, attributable fault: the reconciler raises on the first `(participant_id, step_k)` pair with more than one digest, names the participant, and halts merge eligibility for that participant's branches pending exclusion. The cost is one reconciliation round-trip o..."
  },
  "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": "66086218966ed07f82abea6d12edfc4edb9c3cff0c0939529fb49e60accd6f39",
    "verified_classes": [
      "BranchEquivocationError",
      "BranchRecord"
    ],
    "verified_functions": [
      "reconcile_step",
      "commit_after_reconcile",
      "digest"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "BranchEquivocationError"
    ],
    "sample_fail_closed_invariants": [
      "quorum < 2 cannot cross-check digests; commit-on-merge is unsafe behind an adversarial participant"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "hashlib",
      "typing"
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    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}