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Tool calling
Structured model output that asks software to take an action.
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A tool call is structured model output that asks software to run an action, query, or workflow.
What it means
The model chooses whether to call a tool and fills structured arguments. The application still owns validation, permissions, execution, and error handling.
Why product teams care
Clear tool descriptions, tight schemas, examples, argument validation, and post-call checks reduce failures.
Understudy angle
Understudy can evaluate tool-call traces: correct tool, valid arguments, safe action, useful result, and recovery from errors.
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Tool calling is how models become reliable participants in software workflows.
Write an eval that checks both the selected tool and its arguments.