[Feature Request] Guardrail option for Bedrock KB target (maybe SageMaker too?)

[athewsey]

Amazon Bedrock Guardrails can be applied in a range of ways:

1. ✅ In Bedrock Agents, a guardrail is configured as part of the agent itself, so agent-evaluation already supports testing BR agent targets with guardrail in the loop
2. ❌ In Bedrock KBs, the guardrail ID & version must be specified when calling RetrieveAndGenerate, and agent-evaluation doesn't yet support configuring this
3. ❓If there's interest, maybe it could be interesting to expand the SageMaker Endpoint target to offer an option to use an Amazon Bedrock Guardrail via the ApplyGuardrail API?

Of course it's possible to achieve already by building a custom target, and (3) seems potentially a bit niche - but I manage a workshop that demonstrates agent-evaluation on a KB for which feature (2) would be helpful!