You can resume a subagent's work later, in a new session, without losing its state. The subagent picks up where it stopped.

What it does

Claude Code saves subagent sessions to disk. A resume call restores the subagent's context, recent tool output, and in-flight task list. You can continue the investigation, adjust the prompt, or let the subagent finish a job it paused mid-run. This is the recipe for long-running specialist agents that span days.

When to use it

Long-running research tasks that need human checkpoints.
Migration or audit work that can't finish in one session.
Parallel agent teams where some workers stall and need a human push.
Anything where "start again from scratch" is wasteful.

Gotchas

Resumed context is what the subagent had at pause. Anything that changed in the repo since isn't reflected until the next read.
Very old resumes may reference files that have moved or been deleted.
Resume is per-subagent. Resuming one worker doesn't resume the whole team.

Official docs: https://code.claude.com/docs/en/sub-agents.md#resume-subagents