ADR 0013: Use Azure OpenAI as a feature-gated default¶
Status: Accepted Decision date: 2026-07-22 Owners: Workload owner and architecture owner
Context¶
The source defaults to Vertex AI but already contains a multi-provider adapter. Model capacity, versions, pricing, rate limits, and safety behavior can change independently of the site.
Purpose and decision drivers¶
Remove the production Vertex dependency while preserving portability, graceful degradation, and a bounded AI cost envelope.
Decision¶
Use consumption-based Azure OpenAI as the Azure-native default behind the existing provider adapter. Provision it only after region/capacity/model approval. Use managed identity, content filters, bounded tokens/TPM, dynamic quota off, retries, evaluations, and non-AI fallback.
Consequences and accepted risks¶
- AI is not a dependency for public page delivery.
- Model deployment names and versions are explicit configuration.
- Third-party providers can remain optional fallbacks with Key Vault secrets.
- Image/model parity with Vertex is measured, not assumed.
Alternatives considered¶
- Retain Vertex as default: rejected because the target removes GCP production dependencies.
- Direct OpenAI only: rejected because Azure identity/governance is preferred.
- Remove AI: rejected because AI workflows are part of the source capability inventory.
Validation and revisit triggers¶
Use a golden evaluation dataset, safety tests, 429/timeout tests, cost per generation, and provider fallback evidence. Revisit on model retirement, capacity failure, unacceptable quality, or budget pressure.