# Tool calling

> Tool calling: A model emits a structured request (a tool name and JSON arguments) instead of text; the application checks and runs the function, then…

Canonical: https://llmdojo.dev/glossary/tool-calling

Also called function calling, tool use, tool call, tool calls.

A model emits a structured request (a tool name and JSON arguments) instead of text; the application checks and runs the function, then returns the result into the model's context.

Learn it in the lesson: [The tool-call loop](https://llmdojo.dev/learn/prompt-context-engineering/tools-and-constrained-outputs/the-tool-call-loop) (Prompt and Context Engineering · Tool Instructions and Constrained Outputs).

## Interview questions about Tool calling

- [In tool calling, who executes the tool, and what does the model need in order to use the result?](https://llmdojo.dev/interview/q/in-tool-calling-who-executes-the-tool-and-what-does-the-model)
- [Design an AI chat for a spreadsheet product that turns commands like sum column K or delete row 5 into validated tool calls on the sheet.](https://llmdojo.dev/interview/q/design-an-ai-chat-for-a-spreadsheet-product-that-turns-commands-like)
- [Your logs show most bad tool calls go to one tool. What do you do?](https://llmdojo.dev/interview/q/your-logs-show-most-bad-tool-calls-go-to-one-tool-what)
- [Server logs show a TTFT of 80 ms, yet users of your reasoning assistant say it takes seconds to start answering. Explain the gap.](https://llmdojo.dev/interview/q/server-logs-show-a-ttft-of-80-ms-yet-users-of-your)
- [Your agent has a delete_records tool. What has to happen between the model emitting a call and the delete running?](https://llmdojo.dev/interview/q/your-agent-has-a-delete-records-tool-what-has-to-happen-between)
- [Design a scalable service where an AI agent plans work and calls approved tools without ever bypassing deterministic controls. Cover prompt injection, approvals, budgets and loop termination.](https://llmdojo.dev/interview/q/design-a-scalable-service-where-an-ai-agent-plans-work-and-calls)
- [Walk me through the agent loop.](https://llmdojo.dev/interview/q/walk-me-through-the-agent-loop)
- [What's the difference between a workflow and an agent?](https://llmdojo.dev/interview/q/what-s-the-difference-between-a-workflow-and-an-agent)

## Related
- [Constrained sampling](https://llmdojo.dev/glossary/constrained-sampling)
- [Glossary of every term](https://llmdojo.dev/glossary)