{
  "schema_version": "1.3.0",
  "slug": "why-does-an-instance-of-bft-task-commitment-stall-when-the-quorum-intersects-a-restarted-agent-s-stale-view",
  "title": "Why does an instance of BFT task commitment stall when the quorum intersects a restarted agent's stale view",
  "date_of_record": "2026 November 12",
  "scope": "Applies to leader-based BFT consensus (PBFT/Tendermint-style) used to commit task assignments and attest results among agents where membership is static but individual agents may restart with persisted-but-stale local state. Does not apply to crash-only systems, to systems using verifiable random leader election with no view-change, or to membership-churning configurations where a restarted node is forced through a full re-sync before voting.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/why-does-an-instance-of-bft-task-commitment-stall-when-the-quorum-intersects-a-restarted-agent-s-stale-view.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/why-does-an-instance-of-bft-task-commitment-stall-when-the-quorum-intersects-a-restarted-agent-s-stale-view.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/why-does-an-instance-of-bft-task-commitment-stall-when-the-quorum-intersects-a-restarted-agent-s-stale-view.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1755,
    "python_slice_tokens": 245,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure is not a Byzantine fault and not a liveness failure of the network. It is a **safety-adjacent liveness stall** produced by the interaction of two individually correct mechanisms: (1) the 2f+1 quorum rule for commit, and (2) an agent's right to restart and resume from its last persisted view number. The non-obvious boundary is that a restarted age...",
    "what_was_observed": "During a multi-agent task-commitment run (7 agents, f=2, task = \"attest result of shard 14\"), the following sequence reproduced deterministically: 1. View 3 leader L3 proposed task-assignment certificate `TA(v3, shard14)`. 2. Agents A1, A2, A4, A5 sent `PREPARE(v3, TA)`. 3. A4 crashed and restarted from disk, reloading its last persisted view = 2 and its last vote = `PREPARE(v2, TA_old)`. 4. On restart A4 received th...",
    "condition_of_validity": "This failure requires all of the following to co-occur. If any is absent, the stall does not occur: - **Static membership with restartable agents** whose local vote log persists across restarts. If votes are held only in memory and lost on restart, the agent re-votes and the stall cannot form. - **A recovery rule that treats a persisted vote as binding** (\"n...",
    "decision_boundary": "The operator-facing decision is: **when a leader sees a persistent ack shortfall with high reachability and zero Byzantine suspicion, do you (a) wait for the slow agent, (b) force a view change, or (c) evict and re-sync the restarted agent?** - Waiting (a) is correct only if the shortfall is attributable to latency. The discriminator is whether the missing a...",
    "operational_effect": "The practical consequence is a **liveness cliff that presents as a safety symptom**. Dashboards show a leader that is up, a network that is healthy, and a quorum that will not form — which operators typically triage as a partition or a Byzantine agent. The correct triage is to inspect the *reply type* of each missing ack, not its absence. A missing ack that ..."
  },
  "matched_failure_symptoms": [
    "SPLIT_BRAIN_OR_ZOMBIE_WORKER"
  ],
  "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": "cd37b500beceb6ff8bb620382d32f16cc4988072dc0ff839573cc5a7d28f7823",
    "verified_classes": [
      "StaleViewQuorumError"
    ],
    "verified_functions": [
      "assemble_quorum"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 1,
    "raised_exceptions": [
      "StaleViewQuorumError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}