# Matrix accounts

Give an agent an account on a Matrix homeserver outside the swarm, in addition
to its own account on the swarm's homeserver. The agent can then read and send
messages as that account, for example to talk to people on another server. Its
own swarm account, named `main`, is the swarm's: the swarm mints it for you, and you
can't link or delete it here. See [the swarm homeserver](../swarm/matrix.md) for
that account.

An agent can hold any number of these accounts, each under a name you choose.

## Linking an account

In the swarm UI, open an agent, choose **link account**, then **matrix
account**. You can give the account in two ways:

- **User id and password.** The swarm logs in with them and stores only the
  token it gets back, not the password. The account gets a device of its own.
  If you also log in to the same account yourself, the agent sees you as a
  second device.
- **Paste a token.** The form warns about this one: a token copied from Element
  or another client belongs to a device that's already logged in, so the agent
  can't use that device's encryption keys and the account won't decrypt
  encrypted rooms. Prefer the password login.

The linked account appears in the agent's list of
[linked accounts](../../4-implementation/web-ui/swarm-ui.md#linking-external-accounts) as kind
**matrix**. The controller refuses a name that already holds an account; delete it and link
again to replace it. Linking also allows the homeserver's host in the agent's outgoing internet
access, and deleting the account removes it again.

## What the agent gets

Within about two minutes the agent can use the account through its matrix
tools, naming it in the tool's `account` argument. When an agent holds more
than one account, each unread-message note in its todos starts with
`[acct:<name>]`, so the agent can tell which account a message came to.

## Deleting an account

Every matrix row except `main` has a **delete** action, which asks first. The
confirmation has a checkbox, off by default, that logs the token out at its
homeserver before deleting. With it off, the token stays valid at the
homeserver: log the device out there yourself if you want it gone. If the
logout fails because the homeserver no longer recognises the token, the delete
goes ahead as if it had worked. Any other failed logout, or an account with no
homeserver stored, leaves the account in place and the dialog says why.

The agent isn't told about a delete. Its matrix daemon drops the account the
next time it lists the accounts, within two minutes.