diff --git a/json.go b/json.go
index 129046d..e663fc5 100644
--- a/json.go
+++ b/json.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"os"
 
+	"go.wit.com/lib/protobuf/chatpb"
 	"go.wit.com/log"
 	"google.golang.org/genai"
 )
@@ -53,6 +54,10 @@ func parseJSON(filename string) (*GeminiRequest, error) {
 	if err != nil {
 		return nil, log.Errorf("failed to read file %s: %w", filename, err)
 	}
+	pb := new(chatpb.GeminiRequest)
+	if err := pb.UnmarshalJSON(data); err != nil {
+		return nil, err
+	}
 
 	// Unmarshal the JSON data
 	var req *GeminiRequest
diff --git a/main.go b/main.go
index 273a32f..39cf5cf 100644
--- a/main.go
+++ b/main.go
@@ -65,13 +65,14 @@ func main() {
 	_ = aiClient
 
 	if argv.JsonFile != "" {
-		req, err := parseJSON(argv.JsonFile)
+		jstruct, err := parseJSON(argv.JsonFile)
 		if err != nil {
 			badExit(err)
 		}
-		log.Info("parseJSON() ok. model =", req.Model)
+		log.Info("parseJSON() ok. model =", jstruct.Model)
 
-		genaiContent, err := convertToGenai(req)
+		// Marshal this JSON file into a protobuf
+		genaiContent, err := convertToGenai(jstruct)
 		if err != nil {
 			badExit(err)
 		}