# Agent-as-Tool

> A pattern where one agent exposes a specialist agent as a callable tool instead of handing over the whole conversation.

- Category: Agents & Autonomy
- Stage: Emerging
- Also called: Agent tool, Callable agent
- Canonical: https://www.joelcsaji.com/ai-dictionary/agent-as-tool

## Plain English

The main agent can ask a specialist for one job and keep ownership of the final answer.

## Example

A travel planner calls a visa-checking agent as a tool, receives the result, and continues planning the trip.

## Why it matters

It offers specialization without losing the thread of who owns the user-facing response.

## Related

- [Sub-Agent](https://www.joelcsaji.com/ai-dictionary/sub-agent)
- [Tool Use](https://www.joelcsaji.com/ai-dictionary/tool-use)
- [Supervisor Agent](https://www.joelcsaji.com/ai-dictionary/supervisor-agent)

## Sources

- [OpenAI Agents SDK: Guardrails](https://openai.github.io/openai-agents-python/guardrails/)
- [LangChain: Multi-Agent](https://docs.langchain.com/oss/python/langchain/multi-agent)