For Japanese version, see IModelMessage-jp.md.

IModelMessage (Interface Specification)

1. Responsibility Boundary

IModelMessage is the atomic discourse unit for provider-agnostic model dialogue, offering a normalized message shape across the kernel.

• Role:

Carry speaker role and content to standardize history handling and audit capture.

• Non-role:

Transport details, SDK-specific envelopes, and binary attachment management are out of scope.

2. Contract Signature

namespace AIKernel.Abstractions.Providers;\n\npublic interface IModelMessage\n{\n    string Role { get; }\n    string Content { get; }\n}

3. Related Use Cases

• UC-06 Three-layer buffer boundary:

Serves as a normalized history unit in context isolation flows.

• UC-20 Deterministic replay and audit trail:

Acts as immutable conversation records for replay reconstruction.

4. Governance & Determinism

• Immutability:

Role and Content should be treated as immutable once committed.

• Role normalization:

Implementations should map provider-specific role variants to kernel-standard roles.

• Sequence stability:

Message ordering and payloads must remain stable for deterministic replay parity.

5. Implementation Notes

• Extensibility:

Introduce tool-call or multimodal payloads through layered/derived contracts.

• Serialization:

Keep property shape simple and stable for archival and audit portability.

Changelog

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