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What is Tool Use (LLMs)

GlossaryUser-Facing AI Concepts

The ability of language models to call external tools, APIs, code, search, or databases while completing a task.

Definition

Tool Use (LLMs) is the ability of language models to call external tools, APIs, code, search, or databases while completing a task. In practical AI work, it helps teams connect a concept to data, model behavior, product choices, evaluation, and risk. The useful question is not only what the term means, but how it affects quality, cost, reliability, safety, and decisions in a real workflow.

Example

An assistant calls a calendar API and a document search tool before drafting a useful answer.

Why it matters

Tool Use (LLMs) matters because the ability of language models to call external tools, APIs, code, search, or databases while completing a task can change how teams build, evaluate, choose, or govern AI systems. It directly affects how users ask for results, control outputs, evaluate quality, and avoid unsafe or misleading behavior.

How it works

A user or application provides instructions, context, examples, constraints, and sometimes tool calls, then the model generates or routes the next output. For Tool Use (LLMs), the key is to connect the definition with inputs, assumptions, measurable outcomes, and deployment limits.

Where it is used

  • Used in chatbots, assistants, workflow automation, content tools, customer support, research, and internal knowledge systems.

Limitations

User-facing AI behavior can be sensitive to wording, hidden context, tool permissions, token limits, and changing model behavior.