Tool Use
A model calling external software — search, code, APIs, databases — instead of answering from memory.
Tool use is what lets a model do things it fundamentally cannot do alone: look up current data, run exact calculations, write to a system. The model chooses the tool and the arguments; your code executes it and returns the result. Tools are also the point where a model’s mistakes become real-world actions, so permissions matter.
In practice: Rather than guessing today’s rate, the model calls a currency API.
Where this comes up
- Agentic AI Course in 2026: What to Learn Before Building AI Agents
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