Tool use
A model asking its host application to run a named function with structured arguments, then receiving the result.
Tool use, also called function calling, is the pattern in which a model asks the host application to run a named function with structured arguments, such as looking up a balance or drafting a payment, and then receives the result. The Model Context Protocol standardises how servers expose tools, each with a name, a description and an input schema. The model only proposes the call; the host decides whether to run it, which is where consent, limits and logging belong.
Agent Minute explains this term on 30 November 2026.
Related terms
Model Context Protocol (MCP)An open protocol for connecting AI applications to external tools and data through servers that expose them.MCP serverA service that exposes resources, prompts and tools to AI applications through the Model Context Protocol.AI agentSoftware built on an AI model that pursues a set goal by planning steps and acting through tools or APIs, not only by answering.Excessive agencyGiving an LLM application more functions, permissions or autonomy than needed, so bad outputs cause harmful actions.