What is Tool Call?
A specific invocation of an external tool by an AI agent during task execution.
Definition
A tool call is what happens when an AI agent invokes an external capability — searching the web, querying a database, sending a message, reading a file. It is the fundamental unit of agent-world interaction. In an agent execution trace, you can see a sequence of tool calls the agent made to accomplish its goal. Tools are typically implemented as functions with defined input/output schemas.
Example
A GitHub ops agent might make these tool calls in sequence: `github_list_repos`, `github_list_pull_requests(repo='main-app')`, `slack_post_message(channel='#eng', text='...')`. Each call is a tool call.
Tool Call vs function-calling: What's the difference?
A specific invocation of an external tool by an AI agent during task execution.
Function calling is the model capability. Tool call is the individual invocation — the specific use of that capability during agent execution.