# Setting up Appservice Double Puppet (optional)

Appservice Double Puppet is a homeserver appservice through which bridges (and potentially other services) can impersonate any user on the homeserver.

This is useful for performing [double-puppeting](https://docs.mau.fi/bridges/general/double-puppeting.html) via the [appservice method](https://docs.mau.fi/bridges/general/double-puppeting.html#appservice-method-new). The Appservice Double Puppet service is an implementation of this approach.

Previously, bridges supported performing [double-puppeting](https://docs.mau.fi/bridges/general/double-puppeting.html) with the help of the [Shared Secret Auth password provider module](./configuring-playbook-shared-secret-auth.md), but this old and hacky solution has been superseded by this Appservice Double Puppet method.

## Adjusting the playbook configuration

To enable the Appservice Double Puppet service, add the following configuration to your `inventory/host_vars/matrix.example.com/vars.yml` file:

```yaml
matrix_appservice_double_puppet_enabled: true
```

## Installing

After configuring the playbook, run it with [playbook tags](playbook-tags.md) as below:

<!-- NOTE: let this conservative command run (instead of install-all) to make it clear that failure of the command means something is clearly broken. -->
```sh
ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,ensure-matrix-users-created,start
```

**Notes**:

- The `ensure-matrix-users-created` playbook tag makes the playbook automatically create the bot's user account.

- The shortcut commands with the [`just` program](just.md) are also available: `just install-all` or `just setup-all`

  `just install-all` is useful for maintaining your setup quickly ([2x-5x faster](../CHANGELOG.md#2x-5x-performance-improvements-in-playbook-runtime) than `just setup-all`) when its components remain unchanged. If you adjust your `vars.yml` to remove other components, you'd need to run `just setup-all`, or these components will still remain installed.

## Usage

When enabled, double puppeting will automatically be enabled for all bridges that support double puppeting via the appservice method.
