{
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  "slug": "why-does-an-instance-of-bft-consensus-for-multi-agent-task-commitment-fail-at-the-boundary-between-quorum-certification-and-commitment-finalization",
  "title": "Why does an instance of BFT consensus for multi-agent task commitment fail at the boundary between quorum certification and commitment finalization",
  "date_of_record": "2026 November 13",
  "scope": "Applies to Byzantine fault-tolerant (BFT) consensus protocols used to coordinate task commitment and shared-state agreement among autonomous agents, specifically where a task is considered \"committed\" only after a quorum certificate (QC) is observed and a local finalization step is executed. Does not apply to single-leader crash-fault-tolerant protocols, nor to systems where commitment is defined solely by leader signature without quorum certification.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/why-does-an-instance-of-bft-consensus-for-multi-agent-task-commitment-fail-at-the-boundary-between-quorum-certification-and-commitment-finalization.md",
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  "remnant_summary": {
    "core_distinction": "There are two distinct notions of \"commitment\" in multi-agent BFT systems, and they are routinely conflated: 1. **Quorum-certified**: A supermajority (typically 2f+1 of 3f+1) of replicas have signed off on a task commitment (e.g., \"agent A will execute task T by deadline D\"). A valid QC exists. 2. **Locally finalized**: A given agent has irreversibly bound i...",
    "what_was_observed": "In a 7-replica deployment (f=2, quorum=5) coordinating task commitments across heterogeneous agents, we observed the following sequence: - View v: Leader L1 proposes task commitment block B (task T assigned to agent A). Replicas R1–R5 sign; a valid QC for B exists at v. - R1 and R2 receive the QC and finalize B locally (bind task T to A). - Before R3–R7 receive the QC, a network partition isolates L1. A view change t...",
    "condition_of_validity": "The standard BFT safety argument — \"two conflicting QCs cannot both exist because their quorums intersect in an honest node\" — is valid only under the condition that **every honest replica that contributes a signature to a QC will, upon any subsequent view, refuse to sign a conflicting proposal for the same logical slot**. This condition holds only if: - The...",
    "decision_boundary": "An agent operating in such a system must decide, at each proposal, whether to: - **Sign** (contribute to a potential QC), or - **Finalize** (bind local state to the commitment). These are not the same decision, and the safe rule is asymmetric: - Sign a proposal only if it does not conflict with any QC you have *personally received and durably stored*. Signin...",
    "operational_effect": "When this boundary is crossed, the observable effect is *silent double-commitment*: two agents each hold a locally valid, quorum-certified, irreversibly finalized commitment to the same task. No replica violates its local signing rule; no QC is forged; the safety proof's premises are individually satisfied. The violation is in the *composition* — the protoco..."
  },
  "matched_failure_symptoms": [
    "SPLIT_BRAIN_OR_ZOMBIE_WORKER"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
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      "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"
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    "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"
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  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "2a6a0dd762b334b3cf0ff40ca52b8091d05af1aee0199d76f0e78dfdccb5ebc5",
    "verified_classes": [
      "CommitmentBoundaryError",
      "TaskCommitmentAgent"
    ],
    "verified_functions": [
      "__init__",
      "receive_qc",
      "finalize"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "CommitmentBoundaryError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
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}