An MCP bridge is the interface layer that connects an AI agent to external tools, services, and commands. In practice, it translates model-driven requests into actions such as reading files, calling APIs, querying databases, or launching approved workflows. It sits between the reasoning layer and the execution layer, so it acts as a privilege boundary rather than a simple app endpoint.
This matters in cyber security because a weakly protected bridge can turn automation into remote control. If an attacker can reach the bridge without proper authentication or input checks, they may trigger tool use, expose secrets, tamper with memory stores, or reach shell-capable functions. Defenders treat MCP bridges like other high-value control planes: restrict network exposure, require strong authentication and authorization, minimize dangerous commands, log every tool invocation, and isolate secrets from the runtime. Secure design keeps the agent useful while preventing the bridge from becoming an attack surface.