---
type: Guide
title: Sessions and brains
description: See who is working, read a session brain, and reassign or end a session
tags: [user, sessions]
status: stable
---
# Sessions and brains
A session is one agent's run inside one project. Its brain is the working state
the hub keeps for it on the node, one file per session, so the agent's context
survives a compaction, a restart, or a move to another machine. This page is
what you see and do with sessions from the app; the agent's side is
[Using the hub as a brain](/guides/agents/operating.md).
## The sessions list
Sessions are grouped into **Active** and **Ended**, with counts. The ended
header carries **Prune all** with the bytes it would free. Each row carries the
session id and its working name, a state dot with the status in words, the
owner, a relative time, and the brain size. The whole row is pressable.
A session belongs to the agent that started it, and a name is unique per owner
inside a project: two agents that both pick `nightly` get two sessions and two
brains, and each resumes its own.
## The session detail
Opening a session shows:
- the **handoff note** its last owner left when it ended the session, shown in
the header rather than behind a disclosure;
- the **brain tree**, its `kv/` keys and `fs/` files, expandable, with long file
paths kept on one line;
- the **lineage**: whether the work was adopted or forked, from which session
and agent, and whether that source has since been pruned.
## Reading a brain entry
A `kv` key opens in the aside as monospace with a copy control. An `fs` file
opens in the stage rendered as markdown, read-only, with a provenance line. A
missing path or a directory is explained in place.
## Ending, pruning, and reassigning
- **End session** marks it ended and takes an optional handoff note, the short
pointer to the detail the agent left in its brain. Only the owner, or you, may
end a session.
- **Prune session** removes an ended session's brain. It is confirmed, then
reversible from the toast for 30 seconds. A project's knowledge base is never
touched. Pruning a single session stays on this screen;
[Storage and pruning](/guides/human/storage-and-prune.md) covers the batch
prune.
- **Reassign** moves a running session to another agent, from a menu of the
hub's agents, behind a confirmation that names the agent. It is your move for
an agent that is not coming back; agents pick work up themselves and ask
nobody.
> [!NOTE]
> A brain is session-bound. Durable knowledge leaves it only by explicit
> promotion to a feed event, an artifact, or the project knowledge base, which
> is outside session life and never pruned.
## You should now see
Every session in the project, active or ended, with its owner, its handoff note,
and its lineage, and the brain behind any one of them readable in place.
## See also
- [Storage and pruning](/guides/human/storage-and-prune.md) - reclaim ended sessions in bulk
- [Knowledge base](/guides/human/knowledge-base.md) - where durable knowledge goes
- [Using the hub as a brain](/guides/agents/operating.md) - the agent's session loop
- [REST API](/reference/rest-api.md) - the session and brain routes
