Agent, MCP, Skill, Cli, Model explained at once: conceptual map and three paths for integrating old systems into AI

Author: robinji This article attempts to answer two questions: first, what is the relationship between the five concepts of Agent, Skill, MCP, CLI, and Model, and who calls whom; second, where to start with the old system that has been running in the enterprise for many years before AI can be used. The content includes a general diagram of the relationship between five concepts, a complete relay of a tool call, three paths for old system access (API encapsulation, CLI packaging, RPA cover-up), a complete classification of MCP implementation forms, and practical cases of two architectures, BS and CS. 1. The origin of the incident: The customer is the IT team of a research institute of a large domestic vehicle group. The group management gave them a task, "Let AI penetrate into the old business system." This formulation