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API, Event & Contract Standards

API principles

• stable contracts;
• tenant-scoped requests;
• authenticated principals;
• versioned payloads;
• explicit error semantics;
• idempotency for mutation;
• trace/correlation IDs.

Event principles

Events are immutable facts about occurrence.

They do not themselves imply authorization or promotion.

Command principles

Commands express intent to perform work.

Commands require:

Principal
Work
Capability
Authority
Policy
Idempotency

Result principles

Results include:

Status
Evidence
Receipt
Attribution
Timestamp
Error
Reconciliation State

Schema versioning

Breaking changes require explicit versioning and migration.

Contract hierarchy

Product Contract
→ Platform Contract
→ Service Contract
→ Provider Adapter

Provider API shape must not leak into Product Contract.