Set OpenAI budget alert: embeddings are the app's single billing point of failure

[MinhHaDuong]

Context

On 2026-06-22 Cirdi was down: every query returned HTTP 500. Root cause was an OpenAI 429 insufficient_quota — the OpenAI account ran out of credit. R2R embeds every query with openai/text-embedding-3-small (the retrieval step), so an exhausted OpenAI quota 500s every request even though generation runs on Mistral. Health endpoint stayed ok throughout, which masked the cause.

This is a single point of failure with no early warning, and it will recur.

Actions

• On the OpenAI project behind OPENAI_API_KEY, set a monthly budget limit and a usage/balance alert email (well below the hard cap).
• Document in deploy/ that embeddings depend on OpenAI billing, distinct from the Mistral generation account.
• Note: Anthropic offers no embeddings API, so Claude credit cannot cover this step.

Notes

• Switching embedding providers is not a quick mitigation: the ~1199 stored vectors are tied to text-embedding-3-small and would need full re-embedding.
• Overlaps with Add availability watch service with SMS notification #234 (availability watch / SMS): a balance/usage alert is the upstream signal that Add availability watch service with SMS notification #234's availability probe would otherwise only catch after users hit errors.