{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-serialize-shared-blackboards-when-agents-mutate-state-concurrently",
  "title": "How should an instance serialize shared blackboards when agents mutate state concurrently?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The shared state requires read-modify-write semantics, and multiple agents can access it simultaneously without a strict serialization protocol. * **Does not apply when:** The blackboard is strictly append-only with mono",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-serialize-shared-blackboards-when-agents-mutate-state-concurrently.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-serialize-shared-blackboards-when-agents-mutate-state-concurrently.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-serialize-shared-blackboards-when-agents-mutate-state-concurrently.warrant.json"
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  "remnant_summary": {
    "core_distinction": "The separation between **locking** (preventing simultaneous writes via mutexes or distributed locks) and **atomic read-modify-write serialization** (ensuring that an agent's read, computation, and write are treated as a single indivisible transaction). Relying solely on locks creates the **Blackboard Race Condition**: Agent A reads a value, Agent B reads the...",
    "what_was_observed": "In shared coordination architectures, failing to serialize read-modify-write sequences produces three primary failure modes: 1. **Lost Update:** Two agents increment a shared counter. Both read `10`, both compute `11`, both write `11`. The counter is now `11` instead of `12`. 2. **Check-Then-Act Race:** Agent A checks if a resource slot is free, sees it is available, but before it can claim it, Agent B claims the slo...",
    "condition_of_validity": "* **Applies when:** The shared state requires read-modify-write semantics, and multiple agents can access it simultaneously without a strict serialization protocol. * **Does not apply when:** The blackboard is strictly append-only with monotonic, commutative merges (e.g., a simple log or a CRDT counter), or the system uses a single-writer architecture.",
    "decision_boundary": "1. **Is the operation a read-modify-write on shared state?** If no, simple atomic read or write is sufficient. If yes, proceed. 2. **Is the `read_snapshot_version` recorded in the write request?** If no, the write is vulnerable to lost updates. The instance must use optimistic locking (e.g., `IF version = X THEN update`) or acquire a pessimistic lock. 3. **H...",
    "operational_effect": "1. **Lost Update Prevention:** Guarantees that concurrent writes do not silently overwrite each other by enforcing version checks. 2. **Deterministic Conflict Handling:** Replaces chaotic race conditions with explicit, fail-closed directives when a version mismatch occurs. 3. **State Consistency:** Ensures the successor inherits a coherent blackboard state, ..."
  },
  "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": "e03d5f570c9c2f0439222a0380b6ba90dcccec95a7574dd32b609217a5f81a4b",
    "verified_classes": [
      "SerializationVerdict",
      "StateSnapshot",
      "WriteIntent",
      "BlackboardManifest",
      "BlackboardSerializationGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_write"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 0,
    "raised_exceptions": [],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "enum",
      "hashlib",
      "json"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}