# Sub-Agent

> A focused agent invoked by another agent or workflow to handle a narrower task.

- Category: Agents & Autonomy
- Stage: Rising
- Also called: Worker agent, Specialist agent
- Canonical: https://www.joelcsaji.com/ai-dictionary/sub-agent

## Plain English

A specialist you call when the main agent should not carry every detail in its own context.

## Example

A QA sub-agent opens the app in a browser and reports visual or functional regressions.

## Why it matters

Sub-agents reduce context clutter and make ownership clearer in larger agent systems.

## Related

- [Supervisor Agent](https://www.joelcsaji.com/ai-dictionary/supervisor-agent)
- [A2A](https://www.joelcsaji.com/ai-dictionary/agent2agent)
- [Tool Use](https://www.joelcsaji.com/ai-dictionary/tool-use)

## Sources

- [Google ADK: A2A](https://adk.dev/a2a/intro/)
- [LangChain: Multi-Agent](https://docs.langchain.com/oss/python/langchain/multi-agent)
- [Claude Code: Subagents](https://code.claude.com/docs/en/sub-agents)