Subagents
How an agent delegates a scoped piece of its task to a second session, and what that session is allowed to do.
A subagent in Proliferate is a delegated session: a real session, spawned by another agent, working in the same workspace on a narrower piece of the task.
How to use subagents in Proliferate
There is nothing to install and no separate mode to turn on. Ask the agent for the shape of work you want and it delegates on its own:
The parent creates the child, sends it a prompt, and reads its completion report when it finishes. You can open the child yourself at any point and talk to it like any other session.
Harness-native subagents vs Proliferate subagents
Both exist, and they are not the same thing.
| Harness-native subagent | Proliferate delegated session | |
|---|---|---|
| Examples | A Claude Code Task agent, a Codex collaboration child | Any session created through Proliferate's Workspace tools |
| Where it lives | Inside the parent's session | Its own session, with its own tab |
| What you see | Tool output in the parent transcript | A tab, a roster entry, receipts, and a lifecycle |
| Who controls it | The harness | You and the parent agent |
Native subagents are the harness's own feature and keep working as they always have. This page is about the Proliferate kind.
Understanding the parent-child relation
The runtime injects a set of Workspace tools into ordinary sessions. When an agent uses them to spawn a child, a receipt lands in the parent's transcript — expand it to see the child's name and the prompt it was given.
The relationship is durable, not a one-off call. The parent can message the child, interrupt it, close it, or promote it, and the child's terminal message each turn is relayed back to the parent as a completion report.
Authority is re-checked on every call rather than granted at spawn time, so closing or promoting a session changes what it can do on its very next turn.
Subagents have a slightly narrower role
A delegated session holds the subagent role. Compared with an ordinary agent:
- It cannot create workspaces.
- It cannot create agents of its own.
- Only its parent can message, open, close, or promote it.
- It starts fresh, with the core agent tools, and does not inherit the parent's connected integrations.
It can still message ordinary agents to report findings back.
The narrower role is about orchestration, not sandboxing. A delegated session runs commands in the same checkout, with the same permissions, as its parent.
How subagents appear in the parent session
Child tabs group under a small pill next to the parent's tab in the top tab strip, so delegated work is easy to tell apart from tabs you opened yourself.
The composer's Agents popover lists every delegated session with its status and a Wake button. When a child that scheduled a wake finishes a turn, a receipt appears in the parent transcript that you can click through to read what it found.
How to promote a subagent
Promote turns a delegated session into an ordinary agent on the same conversation. The session id, transcript, and workspace are unchanged; what changes is the role. Use it when a side investigation turns out to be the real work.
Promotion takes effect on the next turn. It does not restart the session or rewrite anything already in the transcript.
How many subagents can a session create?
- Up to 8 active delegated sessions per parent.
- Delegation is one level deep: a delegated session cannot spawn its own.
- A delegated session always lives in the parent's workspace. To hand work to a different checkout, an agent creates a workspace and starts an ordinary session there instead.