/**
* Utilities for describing text length constraints in prompts
*/
interface LengthPromptOptions {
/**
* Ratio (0-1) used to estimate the Japanese character limit from the English max length.
* Defaults to 0.6 (roughly 60%).
*/
japaneseRatio?: number;
/**
* Additional note appended to the length description, e.g., "no line break".
*/
note?: string;
}
const DEFAULT_JAPANESE_RATIO = 0.6;
/**
* Returns a standardized text snippet like
* "max 50 chars, ~30 chars for Japanese" plus optional notes.
*/
export const formatLengthPrompt = (
maxLength: number,
options: LengthPromptOptions = {},
): string => {
const ratio = options.japaneseRatio ?? DEFAULT_JAPANESE_RATIO;
const japaneseMax = Math.max(1, Math.round(maxLength * ratio));
let prompt = `max ${maxLength} chars, ~${japaneseMax} chars for Japanese`;
if (options.note) {
prompt += `, ${options.note}`;
}
return prompt;
};
/**
* Helper to append a standardized length prompt to a base description.
*/
export const withLengthPrompt = (
baseDescription: string,
maxLength: number,
options?: LengthPromptOptions,
): string => {
return `${baseDescription} (${formatLengthPrompt(maxLength, options)})`;
};
