{
  "name": "make_chart",
  "description": "Trace un graphique (PNG, palette UQO) directement à partir de données, sans écrire de code : bar, stacked_bar, hbar, line, area, pie, scatter (avec droite de tendance). Idéal pour comparer des prix ajustés, montrer une courbe âge-vie, une ventilation de dépréciation ou l'évolution d'un indice. Pour des analyses plus complexes, utilise execute_python.",
  "parameters": {
    "type": "object",
    "properties": {
      "type": { "type": "string", "enum": ["bar", "stacked_bar", "hbar", "line", "area", "pie", "scatter"], "default": "bar" },
      "title": { "type": "string" },
      "x": { "type": "array", "items": { "type": ["string", "number"] }, "description": "Catégories ou abscisses." },
      "series": { "type": "array", "items": { "type": "object", "properties": { "name": { "type": "string" }, "values": { "type": "array", "items": { "type": ["number", "string", "null"] } } }, "required": ["values"] } },
      "xlabel": { "type": "string" },
      "ylabel": { "type": "string" },
      "value_format": { "type": "string", "enum": ["number", "currency", "percent"], "default": "number" },
      "filename": { "type": "string" },
      "annotate": { "type": "boolean", "default": true }
    },
    "required": ["series"]
  }
}