Appendix G

REST API & SDK Specification

This appendix defines a reference interface for interacting with Constitutional Execution Infrastructure (CEI). The API exposes governance capabilities independently of implementation language, while SDKs provide strongly typed integrations for client applications.

Applications should request governed execution through stable interfaces rather than embedding governance logic directly in business code.

1. API Design Principles

• Resource-oriented endpoints.
• Stateless request processing.
• Deterministic governance responses.
• Versioned interfaces.
• Language-independent contracts.

2. Core Resources

3. Reference Endpoints

POST   /v1/executions
POST   /v1/authority/check
POST   /v1/admissibility/evaluate

GET    /v1/ledger/{eventId}
GET    /v1/ledger

POST   /v1/replay
GET    /v1/replay/{replayId}

POST   /v1/projections/rebuild
GET    /v1/projections/{projectionId}

4. Example Request

{
  "requestId": "REQ-001",
  "operation": "payment.approve",
  "authorityId": "AUTH-42",
  "evidence": ["EVD-1001"]
}

5. Example Response

{
  "decision": "GO",
  "decisionId": "DEC-9001",
  "policyVersion": "1.2.0",
  "ledgerEvent": "EV-12001",
  "status": "admissible"
}

6. Error Model

7. SDK Responsibilities

• Authentication.
• Request serialization.
• Response validation.
• Retry and timeout handling.
• Version compatibility.
• Replay session helpers.

8. Versioning

Public interfaces should be versioned independently of runtime implementations. Breaking changes should result in a new major API version while preserving compatibility for existing clients where practical.

9. Conformance

• APIs SHOULD return explicit governance decisions.
• SDKs SHOULD preserve protocol compatibility.
• Implementations MUST document supported API versions.
• Replay identifiers SHOULD be stable throughout a replay session.

Appendix Summary

The REST API & SDK Specification provides a stable integration layer for CEI. Applications interact through well-defined contracts while governance behavior remains centralized within the constitutional runtime.

Next: Appendix H — Governance Policy Schema (YAML & JSON).