Option

One entry in a command's options record. The key is the option name.

Property	Type	Description
`schema`	`Schema`	Validates the value, and decides whether the option is required and what it defaults to. Required.
`coerce?`	`CoerceMethod<...>`	Converts the terminal string into the type the schema expects. Not needed when that type is `string`.
`aliases?`	`string[]`	Extra names, written as JavaScript identifiers, so `i` becomes `-i` and `listName` becomes `--list-name`.
`exclusive?`	`boolean`	The option must appear on its own, apart from anything listed in `requires`.
`requires?`	`string[]`	Names that must also be provided when this option is used. Names, not aliases.
`conflictWith?`	`string[]`	Names that cannot be provided together with this option.
`meta?`	`OptionMeta`	Text used by help output and generated docs. Never changes behavior.

Constraints only look at what the user actually provided. They ignore a value that is present because of a schema default. See Constraints.

The coerce helper that you pick also decides how the flag behaves. Boolean flags, repeatable options, and object options all come from it. See Coerce helpers.

OptionMeta

Property	Type	Description
`placeholder?`	`string`	Shown after the flag to hint at the expected value, for example `<path>`.
`description?`	`string`	Plain text. Supports multiple lines and ANSI colors. Preferred in terminal help.
`descriptionMarkdown?`	`string`	Markdown. Preferred in generated Markdown, and formatted when printed to a terminal.
`example?`	`string`	Shown under the description in help, inside a code block in Markdown.
`default?`	`string`	Default shown in help and docs. Does not change the real default. Empty string shows none.
`optional?`	`boolean`	Marks the option optional or required in help and docs only.
`hidden?`	`boolean`	Leave the option out of help and docs.