F_SYSTEM_INVALID_OPTION_ALIAS

Invalid option alias

A field option, option command, or handler flag contains an alias that is not exactly one character.

Updated August 8, 2026

Reproduction

Aliases represent short options and must contain exactly one character:

src/options.ts

import { Flag } from 'func'

class Options {
  @Flag({ aliases: ['v', 'verbose'] })
  verbose = false
}

Use one character for every entry or remove the invalid alias:

src/options.ts

class Options {
  @Flag({ aliases: ['v', 'V'] })
  verbose = false
}