The six ways a template asks the installer a question — a domain, a secret, a choice, and the fields each one takes.

An input is a question the template cannot answer for itself. Every input shares four fields:

Key	Default	Meaning
`key`	—	Required. What `${input.<key>}` names elsewhere in the file.
`type`	—	Required. One of the six below.
`label`	—	Required, at least one character. What the installer reads.
`help`	none	Longer text under the label.
`required`	`true`	Whether the installer must answer before installing.

Then, per type:

`domain`

Nothing further. This is the only way a template can name a host — see No domain. The installer supplies a hostname it controls, and ${input.<key>} is the only thing a domains.host may ever equal.

- key: domain
  type: domain
  label: Where the dashboard answers

`text`

Key	Default	Meaning
`default`	none	Pre-filled, still editable.
`pattern`	none	A regular expression the answer must match.

`number`

Key	Default	Meaning
`default`	none	Pre-filled, still editable.
`min`	none	Lower bound.
`max`	none	Upper bound.

`choice`

Key	Default	Meaning
`default`	none	Which option is pre-selected.
`options`	—	Required, at least two strings.

`secret`

Key	Default	Meaning
`generate`	none	A length in characters, at least `8`.

With generate set, the instance produces the value and shows it once — nobody types a secret into a template. Without it, the installer types the value directly, the way a text input would.

- key: appSecret
  type: secret
  label: The app's session secret
  generate: 32

`store`

Nothing further. Asks the installer to pick an object store that already exists on the instance — the only way a template reaches S3 without carrying anyone's keys. The chosen key is then valid wherever a store key is expected, including attach.store.

Answering an input elsewhere in the file

An input's value is read with ${input.<key>} — in a domains.host, in env, nowhere else. See References for the full grammar.

Inputs