A developer-focused breakdown of three distinct layers in the AI agent stack: tools (callable functions the model invokes), MCP servers (a standardized protocol layer for exposing capabilities portably across clients), and skills (higher-level instruction sets that orchestrate tools toward complex goals). The post clarifies common confusion about how these concepts relate, provides code examples using the Anthropic SDK, and covers security considerations at each layer including least-privilege principles, prompt injection risks, tool poisoning, and human-in-the-loop authorization patterns.
Table of contents
AI Tools Are the Model's Swiss Army KnifeMCP Servers Are the Universal TranslatorAI Skills Direct the WorkKey Differences at a GlanceA Security PerspectiveThree Layers, One SystemSort: