For Japanese version, see IEventBus-jp.md.

IEventBus (Interface Specification)

1. Responsibility Boundary

IEventBus is the neural communication interface for asynchronous event propagation across kernel components with loose coupling.

• Role:

Provide event publish, subscription lifecycle, broadcast delivery, and subscriber-count visibility.

• Non-role:

Distributed transaction guarantees and durable queue semantics are out of scope.

2. Contract Signature

namespace AIKernel.Abstractions.Events;\n\npublic interface IEventBus : IProvider\n{\n    Task PublishAsync(string eventName, object eventData, CancellationToken cancellationToken = default);\n    string Subscribe<T>(string eventName, Func<T, Task> handler);\n    bool Unsubscribe(string subscriptionId);\n    Task BroadcastAsync(string eventName, object eventData, CancellationToken cancellationToken = default);\n    int GetSubscriberCount(string eventName);\n}

3. Related Use Cases

• UC-20 Deterministic replay and audit trail:

Delivers routing/signature/governance events into audit pipelines.

• UC-13 Runtime signature verification:

Broadcasts verification-failure events for immediate containment.

• UC-25 Event bus distribution:

Acts as the common kernel event-delivery substrate.

4. Governance & Determinism

• Side-effect control:

Handlers should minimize interference with primary reasoning flow.

• Ordering:

If event order is semantically critical, implementation should provide ordering guarantees.

• Fail-Closed:

Failures that disable safety monitoring should trigger safe-stop or alternate audit channels.

5. Implementation Notes

• In-memory/distributed portability:

Preserve contract behavior when switching from local bus to distributed backends.

• Type safety:

Since eventData is object, maintain explicit event-name to payload-type mappings in production.

Changelog

• v0.0.0 / v0.0.0.0: Initial draft
• v0.0.1 (2026-05-06): Version upgrade aligned with documentation guidelines