Glossary
Tool Use
An LLM calling external functions to extend its capabilities.
Definition
Tool use — also called function calling — is the ability of a language model to decide it needs an external action (a database query, an API call, a calculator), structure the call, and then incorporate the result into its response. Tool use is what turns LLMs into agents.
Context
Modern enterprise AI relies on tool use as the bridge between the language model and the systems of record. Common tools include search, database queries, API integrations to CRM/ERP/EHR systems, code execution, and other LLMs. The Model Context Protocol (MCP) is an emerging standard for exposing tools to AI systems.
Related terms
Agentic AIAI systems that autonomously execute multi-step tasks to reach a goal.Read Large Language Model (LLM)A neural network trained on massive text corpora to predict next tokens.Read Model Context Protocol (MCP)An open standard for connecting AI systems to tools and data sources.Read AI Evaluation (Evals)The practice of systematically measuring AI system quality.Read