What it means
The parent agent delegates a scoped goal to a subagent with its own tools, context limit, and completion criteria, then merges results or waits for approval.
Why designers should care
Subagent UX needs spawn status, scope labels, cost visibility, and a single approval surface. Users should not chase three hidden chats to understand one task.
Example
A parent “Ship feature” agent spawns a subagent to run tests; the UI shows “Subagent: running vitest (2/4 suites)” with Expand logs and Stop child only.
Common mistakes
- Subagents that act with broader permissions than the parent.
- No way to stop a child without killing the entire parent run.
- Exposing raw subagent chatter instead of a summarized handoff packet.
Frequently asked questions
What is Subagent?
A subagent is a child agent session spawned by a parent orchestrator to handle a subtask, tests, research, lint fixes, while the parent coordinates the overall goal.
Why should designers care about Subagent?
Subagent UX needs spawn status, scope labels, cost visibility, and a single approval surface. Users should not chase three hidden chats to understand one task.
What are common mistakes with Subagent?
Subagents that act with broader permissions than the parent; No way to stop a child without killing the entire parent run; Exposing raw subagent chatter instead of a summarized handoff packet.