As MCP deploys in more production environments, security architecture has become a central community concern. The current MCP security model is evolving on three levels. Transport-level security: MCP is standardizing OAuth 2.0-based authentication and authorization flows, with new stateless transport security considerations — each request must carry complete auth information without relying on long-lived connection identity. Tool-level security: tools declare required permission levels (read-only/read-write/admin), with the Host requesting user confirmation on first call, similar to mobile app permission patterns. Execution-level security: MCP servers can run in isolated sandbox environments (Docker containers or WebAssembly sandboxes), restricting filesystem and network access. Audit logs record each tool call's time, parameters, return status, and execution duration.
In the course, MCP security architecture is a key topic in the Agent Harness production deployment chapter. Learners should establish: MCP security is not a single component's responsibility but collaboration between Host, Server, and Transport. The course provides a security checklist: ① Does each MCP tool declare required permissions? ② Does the Host have confirmation UI? ③ Is the server sandboxed? ④ Are there audit logs? ⑤ Is transport encrypted? Answers to these five questions determine whether an MCP system meets production security standards.