What is subagent?
Quick definition
A specialized AI agent that operates under the coordination of a parent agent, handling specific subtasks within a larger agentic workflow while maintaining communication with its orchestrator.
A subagent is a subordinate AI agent deployed within a multi-agent system to handle targeted responsibilities as part of a larger workflow. Unlike autonomous agents that operate independently, subagents receive instructions from a parent or orchestrator agent, execute domain-specific operations, and report results back to the controlling entity. This architectural pattern enables task decomposition, where complex problems are broken into manageable pieces, each handled by specialized agents optimized for particular domains or operations.
Subagents are particularly valuable in agentic workflows where different capabilities are required sequentially or in parallel. For example, a document-processing system might use one subagent for text extraction, another for content classification, and a third for metadata enrichment. The parent agent coordinates these subagents, aggregates their outputs, and makes higher-level decisions based on combined results. This approach improves maintainability, allows for independent scaling of specific capabilities, and provides better error isolation.
The Model Context Protocol (MCP) facilitates subagent communication through standardized interfaces, allowing agents to discover, invoke, and manage other agents seamlessly. Subagents can themselves spawn child subagents, creating hierarchical agent structures. This design pattern is essential for building reliable, complex AI systems where control flow and error handling must be predictable and auditable.
Example
How it shows up in practice
A content moderation system uses a parent agent that routes user submissions to specialized subagents: one checks for profanity, another analyzes sentiment, and a third verifies against policy documents. The parent collects verdicts and makes the final moderation decision.
Frequently asked questions
How do subagents differ from autonomous agents?
Subagents operate under coordination and instruction from a parent agent, while autonomous agents make independent decisions. Subagents report to their orchestrator and follow delegated tasks.
Can a subagent spawn other subagents?
Yes, subagents can create hierarchical structures by spawning child subagents, enabling nested task decomposition and specialized delegation patterns.
What communication protocol do subagents typically use?
Subagents often use the Model Context Protocol (MCP) or JSON-RPC for standardized communication, allowing seamless integration and message passing with parent agents.
When should I use subagents in my system?
Use subagents when tasks are logically separable, require different expertise, need independent scaling, or benefit from isolated error handling and accountability.