Tool Use
The ability of an AI model to invoke external functions, APIs, or services during a conversation to perform actions beyond text generation. Tool use transforms language models from passive responders into active problem solvers.
Tool use is the foundational capability that separates chatbots from agents. When a model can call tools, it can look up real-time data, execute code, query databases, send emails, or trigger workflows. The model decides which tool to call, constructs the appropriate parameters, and incorporates the result into its response.
For product and growth teams, tool use unlocks automation that was previously impossible without custom engineering. An AI assistant can pull customer data from your CRM, check inventory in your warehouse system, and generate a personalized recommendation, all in a single interaction. The key engineering consideration is designing your tool interfaces to be clear and well-documented, since the model relies on tool descriptions to decide when and how to use them. Poor tool descriptions lead to unreliable agent behavior.
Related Terms
Model Context Protocol (MCP)
An open standard that defines how AI models connect to external tools, data sources, and services through a unified interface. MCP enables agents to dynamically discover and invoke capabilities without hardcoded integrations.
Function Calling
A model capability where the AI generates structured JSON arguments for predefined functions rather than free-form text. Function calling provides a reliable bridge between natural language understanding and programmatic execution.
Agentic Workflow
A multi-step process where an AI agent autonomously plans, executes, and iterates on tasks using tools, reasoning, and feedback loops. Agentic workflows go beyond single-turn interactions to accomplish complex goals.
ReAct Pattern
An agent architecture that interleaves Reasoning and Acting steps, where the model thinks about what to do next, takes an action, observes the result, and repeats. ReAct combines chain-of-thought reasoning with tool use in a unified loop.
Chain of Thought
A prompting technique that instructs the model to break down complex problems into sequential reasoning steps before producing a final answer. Chain of thought significantly improves accuracy on math, logic, and multi-step tasks.
Tree of Thought
An advanced reasoning framework where the model explores multiple solution paths simultaneously, evaluates each branch, and selects the most promising approach. Tree of thought enables more thorough problem-solving than linear chain-of-thought reasoning.