[C5 HL-031] Publish APIs, SDKs, and integration contracts for real consumers #41

Outcome

Expose a stable interface to approved composition and rendition operations.

Placement and activation

• Circle: C5 — Reusable and operated product platform
• System responsibilities: Product / Platform
• Capability coverage: 03 APIs, SDKs & Integrations; 05 Identity, Security & Trust; 08 Quality, Testing & Evaluation; 09 Developer Platform & Tooling; 11 Documentation & Knowledge
• Planning status: Conditional; activate only when the requirement below is met.
• Activation: An actual external consumer needs stable integration.
• Parent epic: [EPIC C5] Reusable and operated product platform #8; master roadmap: [MASTER EPIC] Hole-loop: concentric evolution within Persona / Visual Form Canon #2.

Dependencies

Required prerequisites:

• HL-004 #13 and HL-045 #14: a named consumer, provider ownership, selected interface contract, and source/edition boundaries.
• Verified behavior and compatibility evidence for the operation that the consumer will call.

Conditional dependencies:

• HL-030 #40 applies if the provider is being extracted as a shared engine; a versioned API or local SDK can remain in the existing repository.
• HL-023 #33 applies if the integration consumes publication/edition exports; a clock, rendering, or state interface does not require every export format.
• HL-032 #42 and HL-033 #43 apply if the integration persists protected data or needs account/tenant authorization. HL-034 #44 and HL-035 #45 apply if it is operated as a service.

Complete only the selected consumer path. A local library API does not require a hosted API gateway or service stack.

Acceptance evidence

• Document APIs/schema or local SDK contracts, authentication where needed, input validation, pagination if applicable, errors, idempotency, cancellation, rate limits, and version/deprecation policy.
• Provide one working client example and contract suite for an actual consumer; public SDKs exist only when external use requires them.
• Use explicit adapters for SIMVLTANEA, audiovisual composition, education courseware, source/knowledge custody, or exhibition distribution as selected.
• Review third-party credentials/scopes, webhook signature/replay handling where introduced, licensing, data egress, and failure fallback.
• Publish API reference, integration guide, compatibility matrix, and release notes; separate credentials from downloadable creative packages.

Completion and scope

Attach the actual artifact or commit, relevant verification, limitations, and an artist decision where a composition changes. This issue plans authorized work; creation does not claim implementation or deployment. Preserve independent work/source identities and private source boundaries. Repository creation requires the extraction evidence in HL-004 #13 and HL-045 #14.