Definition
MCP (Model Context Protocol) is an open protocol that standardizes how AI agents connect to and invoke external tools, data sources, and services, letting a single client speak one interface to many providers instead of writing bespoke integrations for each. Because it brokers what tools an agent can see and call at runtime, MCP has also become a focal point for security research — both as an attack surface (malicious or compromised tool servers feeding an agent poisoned instructions) and as a layer where detectors can be inserted to vet tool calls before they execute.