These informations should give the user a good understanding of what the package is and what it is used for. They should be easy to understand, short and to the point.
The summary has to be only one short sentence or a slogan and should describe as good as possible what this package is for.
It should not end with a dot.
The description should give a better understanding of what the package is doing. Sometimes it is handy to copy the first sentence from the website of the project which is usually that what we are looking for here.
There is theoretically no limitation for the length of the description, but it should not exceed more than six lines.