Add support for required fields in parameter generation

Previously, required fields were not handled in OpenAI and Google parameter generation. This update adds logic to include a "required" list for both, ensuring mandatory fields are accurately captured in the schema outputs.

schema/object.go

@@ -18,28 +18,48 @@ type object struct {
 
 func (o object) OpenAIParameters() openai.FunctionParameters {
 	var properties = map[string]openai.FunctionParameters{}
+	var required []string
 	for k, v := range o.fields {
 		properties[k] = v.OpenAIParameters()
+		if v.Required() {
+			required = append(required, k)
+		}
 	}
 
-	return openai.FunctionParameters{
+	var res = openai.FunctionParameters{
 		"type":        "object",
 		"description": o.Description(),
 		"properties":  properties,
 	}
+
+	if len(required) > 0 {
+		res["required"] = required
+	}
+
+	return res
 }
 
 func (o object) GoogleParameters() *genai.Schema {
 	var properties = map[string]*genai.Schema{}
+	var required []string
 	for k, v := range o.fields {
 		properties[k] = v.GoogleParameters()
+		if v.Required() {
+			required = append(required, k)
+		}
 	}
 
-	return &genai.Schema{
+	var res = &genai.Schema{
 		Type:        genai.TypeObject,
 		Description: o.Description(),
 		Properties:  properties,
 	}
+
+	if len(required) > 0 {
+		res.Required = required
+	}
+
+	return res
 }
 
 func (o object) FromAny(val any) (reflect.Value, error) {