Retrofit, don’t rebuild: Agentic overlays for transforming legacy enterprise services
TL;DR
AWS and Cisco authors propose agentic overlays as thin layers on top of existing REST services so they can participate in A2A communication. The REST business logic stays unchanged: the overlay translates JSON-RPC/A2A messages into REST payloads, calls internal endpoints, and wraps responses back into agent-friendly format.
Nauti's Take
This is one of the more realistic enterprise AI patterns: do not throw away existing services, expose them in an agent-ready way. That is how agents are more likely to enter companies, because nobody wants to rewrite production business logic just for a new protocol.
Still, a thin wrapper is not a free pass. If the overlay mistranslates permissions, context, or errors, it becomes a second API layer that is harder to reason about.
Briefingshow
Many companies have stable REST systems but no clean bridge into agentic workflows. The useful part is that this treats migration as an interface problem, not a full rebuild. The catch: auth, monitoring, error semantics, and scaling move into that thin layer and need the same rigor as the underlying API.
Sources
