{
  "schema_version": "1.3.0",
  "slug": "across-what-transactional-outbox-and-relay-claim-gates-must-an-instance-decouple-database-commits-from-message-publishing-to-prevent-dual-write-phantom-and-lost-events",
  "title": "Across what transactional-outbox and relay-claim gates must an instance decouple database commits from message publishing to prevent dual-write phantom and lost events?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** An AI instance, autonomous coding agent, or backend service mutates state in a transactional database and must reliably emit corresponding domain events, cache invalidation messages, or background jobs to a separate mess",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/across-what-transactional-outbox-and-relay-claim-gates-must-an-instance-decouple-database-commits-from-message-publishing-to-prevent-dual-write-phantom-and-lost-events.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/across-what-transactional-outbox-and-relay-claim-gates-must-an-instance-decouple-database-commits-from-message-publishing-to-prevent-dual-write-phantom-and-lost-events.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/across-what-transactional-outbox-and-relay-claim-gates-must-an-instance-decouple-database-commits-from-message-publishing-to-prevent-dual-write-phantom-and-lost-events.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 3478,
    "python_slice_tokens": 911,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "Autonomous systems constantly need to update a relational database record (such as inserting a new customer order or updating an account balance) and simultaneously publish an event to a message broker or webhook queue (`order.created`) so downstream services can react. A foundational distributed-systems consistency failure occurs when an instance performs a...",
    "what_was_observed": "In e-commerce checkout handlers, billing ledgers, and multi-agent event buses, instances operating without a transactional outbox and leased relay exhibit four primary failure modes: 1. **Post-Commit Broker Outage Drops Events Forever:** An API handler runs `await session.commit()` to save a user signup, then calls `await kafka_producer.send(\"user.created\", payload)`. When the Kafka broker experiences a 3-second lead...",
    "condition_of_validity": "* **Applies when:** An AI instance, autonomous coding agent, or backend service mutates state in a transactional database and must reliably emit corresponding domain events, cache invalidation messages, or background jobs to a separate message broker or external queue. * **Does not apply when:** Emitting best-effort, non-critical telemetry (such as CPU utili...",
    "decision_boundary": "1. **Look at your request handler: are you calling `db.commit()` and `broker.publish()` one after the other?** Stop doing direct dual writes. Instead, insert the event payload into a `transactional_outbox` table inside the exact same database transaction as your business write so they commit or roll back together. 2. **How does your background relay worker p...",
    "operational_effect": "1. **Zero Uncoordinated Dual Writes:** Across all generated mutation handlers, the instance never calls an external message broker directly alongside a database transaction, co-writing outgoing events into a local `transactional_outbox` table within the same ACID commit. 2. **Leased, Ordered Relay Draining:** Outbox relay workers claim batches atomically in ..."
  },
  "matched_failure_symptoms": [
    "SQLITE_BUSY_OR_DEADLOCK",
    "DUPLICATE_MUTATION_OR_BILLING"
  ],
  "composition_edges": {
    "primary_domain": "network_timeout_and_idempotent_retries",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/beneath-what-concurrency-and-backpressure-ceilings-must-an-instance-throttle-fan-out-tasks-to-prevent-file-descriptor-and-connection-pool-starvation.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"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/across-what-readiness-unregistration-and-in-flight-drain-gates-must-an-instance-sequence-sigterm-shutdown-to-prevent-dropped-requests-and-truncated-writes.md",
      "https://corpusfetch.com/c/across-what-bounded-queue-admission-control-and-load-shedding-gates-must-an-instance-manage-concurrency-to-prevent-unbounded-memory-growth-and-tail-latency-collapse.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/across-what-deadline-propagation-and-cancellation-cascade-gates-must-an-instance-govern-grpc-and-http2-calls-to-prevent-zombie-worker-exhaustion-and-wasted-compute.md",
      "https://corpusfetch.com/c/across-what-durable-step-ledger-and-reverse-compensation-gates-must-an-instance-orchestrate-multi-service-sagas-to-prevent-orphaned-partial-mutations.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "4b5b6405c605499c015bd2d2d0a0c29ce1dba43cdf3b91ebb5ffb8897b86661b",
    "verified_classes": [
      "OutboxEventRecord",
      "TransactionalOutboxStore"
    ],
    "verified_functions": [
      "__init__",
      "_init_schema",
      "stage_event_in_tx",
      "claim_batch",
      "drain_outbox_batch",
      "verify_outbox_invariants"
    ],
    "verified_functions_count": 6,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "ValueError"
    ],
    "sample_fail_closed_invariants": [
      "assert batch_size > 0 and lease_seconds > 0.0",
      "batch_size must be strictly within (0, 1000]",
      "lease_seconds must be strictly positive"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "json",
      "sqlite3",
      "time",
      "typing",
      "uuid"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}