Nvidia Openshell solves most of the hard problems I've run into while building stuff in this space.

Observability is, for my purposes, solved by a given framework supporting OpenTelemetry.

Guardrails is where I've gotten the most value of openshell being a neat package. Agent workload scope is written as policy in openshell, and capability is backed by openshell handling all execution.

Monitoring/deployment/versioning is helped as well, depending on how agents/runners are slotted into the system. Deployment namely is quite well supported- openshell has kube/helm bits that are experimental atm, but seem like a logical approach imho.

Evals and a/b testing isnt something ive explored in depth, considering that agents with composable tool sets + frontier models are beyond my expectations already.