Agent
ConceptDefinition
An AI system that can autonomously plan and execute multi-step tasks by calling tools, browsing the web, writing code, and interacting with external services — all without continuous human intervention.
Related Terms
Tool Use
The ability of an LLM to invoke external tools — web search, code execution, calculators, APIs — during inference. The model decides when and how to call tools, receives the result, and incorporates it into its response.
Function Calling
A structured capability where the model outputs a JSON object describing which function to call and with what arguments, rather than plain text. The calling application executes the function and feeds the result back. Standard in GPT-4, Claude, and Gemini.
Chain-of-Thought
A prompting technique where the model is instructed (or naturally encouraged) to output intermediate reasoning steps before a final answer. Dramatically improves performance on multi-step math, logic, and coding problems.