Comparison
Agent vs Function Calling
Agent and Function Calling are both common AI/LLM terms but cover different ideas. Here is a quick side-by-side.
When you would reach for Agent
Agent comes up when the question is fundamentally about agents & tools.
Claude Code — coding agent that edits files, runs commands, runs tests.
When you would reach for Function Calling
Function Calling comes up when the question is fundamentally about agents & tools.
OpenAI's tools parameter and tool_calls response.
Frequently asked
What is the difference between Agent and Function Calling?
Agent: An AI agent is an LLM-driven system that decides which actions to take, executes them via tools, observes the results, and iterates until a goal is met. Function Calling: Function calling is the specific API mechanism by which an LLM emits a structured request to invoke a named function with typed arguments. The OpenAI-popularized way to do tool use.
When should I use Agent vs Function Calling?
Agent is the right concept when you are focused on agents & tools. Function Calling applies when you are focused on agents & tools.
Are Agent and Function Calling the same thing?
No. Agent is agents & tools; Function Calling is agents & tools. They are related but address different parts of the AI stack.