{
  "schema_version": "1.3.0",
  "slug": "when-must-an-instance-refuse-to-commit-the-quorum-intersection-invariant-under-partial-asynchrony-in-multi-agent-task-commitment",
  "title": "When must an instance refuse to commit: the quorum-intersection invariant under partial asynchrony in multi-agent task commitment",
  "date_of_record": "2026 November 11",
  "scope": "Applies to BFT consensus protocols used to bind a set of agents to a task commitment and to agree on a result digest when up to *f* of *n* = 3*f*+1 agents may be Byzantine and message delay is unbounded but eventual (partial synchrony). Does not apply to crash-fault-only settings, to settings with authenticated clocks or trusted hardware, or to protocols that finalize outside a quorum certificate (e.g., single-leader commit without a signed certificate).",
  "projections": {
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    "method_python_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-commit-the-quorum-intersection-invariant-under-partial-asynchrony-in-multi-agent-task-commitment.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-commit-the-quorum-intersection-invariant-under-partial-asynchrony-in-multi-agent-task-commitment.warrant.json"
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  "remnant_summary": {
    "core_distinction": "The non-obvious boundary is between **safety under asynchrony** and **liveness under asynchrony**, and specifically where the two are traded at the moment of *commitment* rather than at the moment of *proposal*. Most operational guidance treats \"commit\" as the safe, boring step: once a quorum certificate exists, the value is decided and the only remaining qu...",
    "what_was_observed": "In a 7-agent (f = 2) deployment running a PBFT-derived protocol with view changes triggered on leader timeout, the following sequence was reproduced under injected delay: 1. View *v* has leader L_v. L_v proposes a commitment `C = (task_id, deadline, required_result_schema, obligated_set = {A1..A5})`. 2. Replicas A1, A2, A3, A4 prepare and commit `C`. A quorum certificate `QC_v(C)` with 5 signatures (A1–A5, including ...",
    "condition_of_validity": "The quorum-intersection invariant for task commitment holds only when all three of the following are true simultaneously: 1. **Obligation is explicit and signed.** The obligated set is a field inside the signed proposal, not derived from the certificate's signer set and not computed from a membership view. The certificate signs the obligation. 2. **Membershi...",
    "decision_boundary": "An agent must refuse to treat a commitment certificate as actionable — and must raise, not silently proceed — when: - The certificate does not carry an explicit, signed obligated set, **or** - The agent's local membership view has diverged from the certificate's view in a way that removes any obligated agent, **or** - The agent is asked to certify a result w...",
    "operational_effect": "After enforcing the boundary, the observed behavior changed in three measurable ways: - **Stalled tasks became visible.** Commitments with missing or divergent obligated sets surfaced as explicit `UncommittableObligation` conditions rather than as silent deadline misses. The mean time to detect an orphaned obligation dropped from \"at deadline\" (minutes to ho..."
  },
  "matched_failure_symptoms": [
    "SPLIT_BRAIN_OR_ZOMBIE_WORKER"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
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      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
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      "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": "51d4c242904653228175b5bd418fa95020c47d78eaad0d870e57500b2b1f84d9",
    "verified_classes": [
      "UncommittableObligation",
      "CommitmentCertificate"
    ],
    "verified_functions": [
      "verify_actionable",
      "verify_result_intersection",
      "quorum_size"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "UncommittableObligation"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
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      "dataclasses",
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    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
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}