{
  "schema_version": "1.3.0",
  "slug": "in-what-scenarios-must-an-instance-treat-consensus-gated-commit-as-invalid-when-the-speculative-tree-has-already-diverged-across-branches",
  "title": "In what scenarios must an instance treat consensus-gated commit as invalid when the speculative tree has already diverged across branches",
  "date_of_record": "2026 November 11",
  "scope": "Applies to speculative agent tree search systems where multiple branches expand in parallel and a commit is gated on a quorum of branch-level votes. Does not apply to single-branch speculative decoding, nor to tree search where commit is decided by an external orchestrator that observes the full tree state.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-consensus-gated-commit-as-invalid-when-the-speculative-tree-has-already-diverged-across-branches.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-consensus-gated-commit-as-invalid-when-the-speculative-tree-has-already-diverged-across-branches.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-consensus-gated-commit-as-invalid-when-the-speculative-tree-has-already-diverged-across-branches.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1740,
    "python_slice_tokens": 396,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The non-obvious boundary is between *consensus over branch outcomes* and *consensus over branch provenance*. A consensus-gated commit protocol normally asks: \"do a quorum of branches agree that this node's value/action is correct?\" That question is well-posed only if every voting branch shares a common ancestor state and a common observation history up to th...",
    "what_was_observed": "In a tree-search agent with width 8 and depth 5, branches were forked after a shared prefix, then allowed to issue tool calls independently. A commit gate required ≥5 of 8 branches to endorse a candidate action. On a specific class of tasks (multi-step retrieval where an early tool call returned a partially-populated cache), four branches forked *before* the cache was populated and four forked *after*. The post-cache...",
    "condition_of_validity": "Consensus-gated commit is valid if and only if, at commit time, the following holds for the set of voting branches V: 1. Every branch in V has the same `parent_state_hash` at the commit node's parent. 2. Every branch in V has an observation log that is a prefix-consistent superset of the commit node's required observations — no voter is missing an observatio...",
    "decision_boundary": "The decision an agent must make at the gate is not \"did quorum pass?\" but \"is quorum *applicable*?\" The boundary: - **Commit directly** when all four conditions hold and quorum passes. - **Commit with reduced confidence / re-verify** when conditions 1–2 hold but condition 3 is unknown (no ledger). Treat as a single-sample commit and schedule a verification s...",
    "operational_effect": "Enforcing the provenance check changes the commit rate and the error profile. In the observed system, adding a `parent_state_hash` equality check plus an observation-log prefix check eliminated the silent-wrong-commit class entirely; the cost was a ~12% increase in re-expansion events on tasks with early tool-call nondeterminism, because those tasks legitima..."
  },
  "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": "17ea519775260d190e7b944b0997b638fb169498ff448424b1b637a1c6323192",
    "verified_classes": [
      "DivergentConsensusError",
      "Branch"
    ],
    "verified_functions": [
      "_log_hash",
      "validate_voters",
      "consensus_commit"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "DivergentConsensusError"
    ],
    "sample_fail_closed_invariants": [
      "empty voter set: quorum is undefined",
      "voter observation logs are not prefix-consistent; some voter is missing an observation used by another"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "hashlib",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}