Do not repeat system prompt for chat templating (#2241)

server/routes.go

@@ -239,6 +239,11 @@ func GenerateHandler(c *gin.Context) {
 			Prompt: req.Prompt,
 			First:  len(req.Context) == 0,
 		}
+
+		if promptVars.System == "" {
+			promptVars.System = model.System
+		}
+
 		p, err := model.PreResponsePrompt(promptVars)
 		if err != nil {
 			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})