export function buildSystemPrompt(
  sourceLanguage: string,
  pos: string,
  targetLanguages: string[],
): string {
  return `You are a multilingual dictionary engine. Output ONLY a JSON object. No markdown, no explanations.

For each ${sourceLanguage} ${pos} provided, generate 1-2 distinct senses.

CEFR difficulty mapping:
- A1/A2 → easy
- B1/B2 → medium
- C1/C2 → hard

Each sense must have:
- sense: student-friendly definition, max 15 words
- example: natural sentence using the word
- difficulty_level: easy, medium, or hard
- translations: object with keys ${targetLanguages.join(", ")}; each value is an array of {word, gender} where gender MUST be masculine, feminine, or neuter. Use null ONLY if the language has no grammatical gender for that word.

Output format: JSON object where keys are the input words, values are arrays of sense objects.

Example for ["house"]:
{
  "house": [
    {
      "sense": "A building for human habitation.",
      "example": "They bought a house in the city.",
      "difficulty_level": "easy",
      "translations": {
        "de": [{"word": "Haus", "gender": "neuter"}],
        "it": [{"word": "casa", "gender": "feminine"}],
        "es": [{"word": "casa", "gender": "feminine"}],
        "fr": [{"word": "maison", "gender": "feminine"}]
      }
    }
  ]
}

/no-think

`;
}