feat(OMN-2084): Add CI handshake enforcement workflow

.claude/architecture-handshake.md

@@ -1,8 +1,8 @@
 <!-- HANDSHAKE_METADATA
 source: omnibase_core/architecture-handshakes/repos/omnibase_infra.md
-source_version: 0.13.1
-source_sha256: cb694fe620ef8224ebbe53852d7fd7b498aab3249913bc4d07c8c3cbb7552762
-installed_at: 2026-02-03T14:43:13Z
+source_version: 0.16.0
+source_sha256: 1ffa2bd30b553ea05cd62444800a4ae5215826be9f073480254c3f408580e93f
+installed_at: 2026-02-10T17:46:59Z
 installed_by: jonah
 -->
 
@@ -25,6 +25,18 @@ installed_by: jonah
 - Handler implementations
 - Infrastructure adapters
 
+## Platform-Wide Rules
+
+1. **No backwards compatibility** - Breaking changes always acceptable. No deprecation periods, shims, or migration paths.
+2. **Delete old code immediately** - Never leave deprecated code "for reference." If unused, delete it.
+3. **No speculative refactors** - Only make changes that are directly requested or clearly necessary.
+4. **No silent schema changes** - All schema changes must be explicit and deliberate.
+5. **Frozen event schemas** - All models crossing boundaries (events, intents, actions, envelopes, projections) must use `frozen=True`. Internal mutable state is fine.
+6. **Explicit timestamps** - Never use `datetime.now()` defaults. Inject timestamps explicitly.
+7. **No hardcoded configuration** - All config via `.env` or Pydantic Settings. No localhost defaults.
+8. **Kafka is required infrastructure** - Use async/non-blocking patterns. Never block the calling thread waiting for Kafka acks.
+9. **No `# type: ignore` without justification** - Requires explanation comment and ticket reference.
+
 ## Rules the Agent Must Obey
 
 1. **Nodes MUST be declarative** - `node.py` extends base class with NO custom logic
@@ -33,11 +45,9 @@ installed_by: jonah
 4. **Orchestrators emit, never return** - Cannot return `result`
 5. **Contracts are source of truth** - YAML contracts define behavior
 6. **Container injection required** - All services via `ModelONEXContainer`
-7. **Never block on Kafka** - Kafka is optional; operations must succeed without it
 
 ## Non-Goals (DO NOT)
 
-- ❌ No backwards compatibility - change freely, no deprecation periods
 - ❌ No versioned directories (`v1_0_0/`, `v2/`) - version through contract.yaml fields only
 - ❌ No convenience over correctness - contract violations fail loudly
 - ❌ No business logic in nodes - nodes coordinate, handlers compute
@@ -48,11 +58,10 @@ installed_by: jonah
 - Custom logic in `node.py` beyond base class extension
 - Error handling in nodes (belongs in handlers)
 - Direct Kafka/Postgres calls in nodes (use effect handlers)
-- Leaving deprecated code "for reference" - DELETE IT
 
 ## Layer Boundaries
 
-```text
+```
 omnibase_core (contracts, models)
     ↑ imported by
 omnibase_spi (protocols)

.github/workflows/check-handshake.yml

@@ -0,0 +1,53 @@
+name: Check Architecture Handshake
+
+on:
+  push:
+    branches: [main, develop]
+    paths:
+      - '.claude/architecture-handshake.md'
+      - '.github/workflows/check-handshake.yml'
+  pull_request:
+    branches: [main, develop]
+    paths:
+      - '.claude/architecture-handshake.md'
+      - '.github/workflows/check-handshake.yml'
+  workflow_dispatch:
+
+jobs:
+  check-handshake:
+    name: Check architecture handshake
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+
+      - name: Checkout omnibase_core
+        uses: actions/checkout@v4
+        with:
+          repository: OmniNode-ai/omnibase_core
+          # Pinned to omnibase_core main as of 2026-02-10.
+          # Update by running: gh api repos/OmniNode-ai/omnibase_core/commits/main --jq '.sha'
+          ref: 4dc7a0adf299e47eef57ab9950b0f0a587638a3e
+          path: omnibase_core
+          # OMNIBASE_CORE_TOKEN is required when omnibase_core is private.
+          # GITHUB_TOKEN only has read access to the current repo by default.
+          token: ${{ secrets.OMNIBASE_CORE_TOKEN || secrets.GITHUB_TOKEN }}
+
+      - name: Verify omnibase_core checkout
+        run: |
+          if [ ! -f omnibase_core/architecture-handshakes/check-handshake.sh ]; then
+            echo "::error::Failed to checkout omnibase_core or check-handshake.sh not found."
+            echo ""
+            echo "Diagnostic information:"
+            echo "  omnibase_core directory exists: $([ -d omnibase_core ] && echo 'yes' || echo 'no')"
+            echo "  omnibase_core is empty: $([ -z "$(ls -A omnibase_core 2>/dev/null)" ] && echo 'yes' || echo 'no')"
+            echo ""
+            echo "If omnibase_core is private, GITHUB_TOKEN does not have cross-repo access."
+            echo "Set the OMNIBASE_CORE_TOKEN repository secret with a PAT that has repo scope."
+            exit 1
+          fi
+
+      - name: Check architecture handshake
+        run: bash omnibase_core/architecture-handshakes/check-handshake.sh

docs/decisions/adr-kafka-required-infrastructure.md

@@ -0,0 +1,38 @@
+# ADR: Kafka is Required Infrastructure (Rule #8)
+
+**Status**: Accepted
+**Date**: 2026-02-10
+**Ticket**: OMN-2084
+
+## Context
+
+The platform originally operated under the rule "Never block on Kafka — Kafka is optional;
+operations must succeed without it." This was encoded in the architecture handshake as a
+constraint that all repos observed.
+
+As the platform matured, Kafka became the sole event transport for inter-node communication,
+projection publishing, DLQ routing, and wiring health monitoring. The "optional Kafka"
+invariant was no longer accurate — every production deployment requires a running Kafka
+cluster, and "graceful degradation" without Kafka meant silently dropping events.
+
+## Decision
+
+**Kafka is required infrastructure** (platform-wide rule #8). Specifically:
+
+- Connection failures during `start()` raise and must be treated as fatal by callers.
+- There is no "degraded mode" — if Kafka is unreachable, the node cannot operate.
+- Async/non-blocking patterns are still required to avoid blocking the calling thread
+  while waiting for Kafka acks.
+- Resilience patterns (circuit breaker, retry with backoff) protect against *transient*
+  broker failures, not permanent unavailability.
+
+This replaces the previous rule "Never block on Kafka."
+
+## Consequences
+
+- Callers of `EventBusKafka.start()` and `ProviderKafkaProducer.create()` must not
+  swallow connection errors.
+- Integration tests that previously mocked Kafka away need explicit opt-in for
+  Kafka-less testing via markers (`@pytest.mark.no_kafka`).
+- The `localhost:9092` defaults in config models remain as development conveniences but
+  must be overridden in deployed environments (per rule #7: no hardcoded configuration).

docs/operations/EVENT_BUS_OPERATIONS_RUNBOOK.md

@@ -12,7 +12,7 @@ The EventBusKafka provides production-grade message streaming using Apache Kafka
 - **Circuit breaker** for connection failure protection
 - **Retry with exponential backoff** on publish failures
 - **Dead letter queue (DLQ)** for failed message processing
-- **Graceful degradation** when Kafka is unavailable
+- **Resilience** against transient broker failures (per platform-wide rule #8: Kafka is required infrastructure)
 
 **Source Location**: `src/omnibase_infra/event_bus/event_bus_kafka.py`
 
@@ -57,7 +57,7 @@ All configuration is managed through environment variables with sensible default
 
 | Variable | Default | Range | Description |
 |----------|---------|-------|-------------|
-| `KAFKA_BOOTSTRAP_SERVERS` | `localhost:9092` | - | Comma-separated broker addresses |
+| `KAFKA_BOOTSTRAP_SERVERS` | `localhost:9092` | - | Comma-separated broker addresses. **Must be overridden** — per rule #7 localhost defaults are for local development only; per rule #8 Kafka is required infrastructure. |
 | `KAFKA_ENVIRONMENT` | `local` | - | Environment identifier (e.g., `dev`, `staging`, `prod`) |
 | `KAFKA_GROUP` | `default` | - | Consumer group identifier |
 

src/omnibase_infra/event_bus/event_bus_kafka.py

@@ -12,7 +12,7 @@
     - Circuit breaker for connection failure protection
     - Retry with exponential backoff on publish failures
     - Dead letter queue (DLQ) for failed message processing
-    - Graceful degradation when Kafka is unavailable
+    - Resilience against transient Kafka broker failures (per platform-wide rule #8)
     - Support for environment/group-based routing
     - Proper producer/consumer lifecycle management
 
@@ -220,8 +220,8 @@ class EventBusKafka(
 
     Implements ProtocolEventBus interface using Apache Kafka (via aiokafka)
     with resilience patterns including circuit breaker, retry with exponential
-    backoff, dead letter queue support, and graceful degradation when Kafka
-    is unavailable.
+    backoff, dead letter queue support, and resilience against transient
+    broker failures (per platform-wide rule #8: Kafka is required infrastructure).
 
     Features:
         - Topic-based message routing with Kafka partitioning
@@ -484,12 +484,13 @@ async def start(self) -> None:
         """Start the event bus and connect to Kafka.
 
         Initializes the Kafka producer with connection retry and circuit
-        breaker protection. If connection fails, the bus operates in
-        degraded mode where publishes will fail gracefully.
+        breaker protection. Per platform-wide rule #8, Kafka is required
+        infrastructure — connection failures raise and must be treated as
+        fatal by the caller.
 
         Raises:
-            InfraConnectionError: If connection fails after all retries and
-                circuit breaker is open
+            InfraTimeoutError: If connection times out
+            InfraConnectionError: If connection fails after retries
         """
         if self._started:
             logger.debug("EventBusKafka already started")

src/omnibase_infra/runtime/providers/provider_kafka_producer.py

@@ -3,7 +3,8 @@
 """Kafka producer provider.
 
 Creates AIOKafkaProducer instances from environment-driven configuration.
-Respects architecture constraint #7: Never block on Kafka.
+Respects platform-wide rule #8: Kafka is required infrastructure —
+use async/non-blocking patterns.
 
 Part of OMN-1976: Contract dependency materialization.
 """
@@ -27,8 +28,9 @@ class ProviderKafkaProducer:
     Producers are created from KAFKA_* environment variables and shared
     across all contracts that declare kafka_producer dependencies.
 
-    Per architecture constraint #7: Kafka is optional. Creation failures
-    are logged but do not block startup.
+    Per platform-wide rule #8: Kafka is required infrastructure.
+    Creation failures propagate to the caller — callers must treat them
+    as fatal. Uses async patterns to avoid blocking the calling thread.
     """
 
     def __init__(self, config: ModelKafkaProducerConfig) -> None: