请问这样的推荐信算什么？

问国外暑研的教授要了推荐信，推荐信里写了" A visit of three months was too short for *** to show her full potential of doing research but she is a nice person to work with"
其他的个人品质什么的也没写，请问这是弱推还是黑推啊？
这样的推荐信会不会有反作用啊？
无比担心。。。。