Generic API Design Rules for Google Gemini

# Generic API Design Rules for Google Gemini

## Contracts
- Version API contracts intentionally and document breaking changes.
- Use consistent error shape: code, message, optional details.
- Prefer explicit nullable fields over overloaded semantics.

## Reliability
- Idempotent writes where retries are expected.
- Timeouts and retry budgets on all network calls.
- Pagination for list endpoints; never return unbounded datasets.

## Observability
- Correlation/request IDs propagated across service boundaries.
- Log request/response metadata (not sensitive payloads).
- Emit metrics for rate, errors, and p95/p99 latency.