Where does OAuth help with MCP, and where is it not enough?

OAuth can help MCP by authorizing access to user-scoped or application-scoped resources, especially when tools connect to systems that already use OAuth. But OAuth is not enough by itself for full agent governance. Enterprises still need workload identity, least-privilege tool policies, audit trails, workflow context, and recovery behavior. OAuth may say a client can access a resource; it does not automatically explain which agent action led to the call or whether the tool use fits the workflow policy. Diagrid's MCP security framing adds identity, policy, and observability around the broader agent execution path.