Dynamic Client Registration (DCR) is crucial for scaling Model Context Protocol (MCP) deployments by allowing clients to register at runtime, but it also introduces significant security vulnerabilities due to its open nature. Remote MCP servers require robust protection as they are exposed to global threats, unlike local servers which naturally limit access to clients on the same network. The primary challenge is ensuring security while maintaining the scalability benefits of DCR, which is necessary for MCP's potential to connect limitless AI agents with servers. Emerging standards like SEP-991 propose using Client ID Metadata Documents to improve trust, although they are not yet officially part of the MCP specification. Practical solutions for hardening DCR implementations include implementing layered verification processes, using IP reputation services, and deploying risk-based controls. Descope offers a comprehensive identity infrastructure to address these vulnerabilities, integrating verification workflows and granular access control to ensure that DCR’s scalability does not compromise security.