I have created two new tags (though one was created for me because I was too slow!). One for [clannad] and for [reborn]. I set the description out like this. I'll be using Kuroshitsuji/Black Butler as an example:
A shounen manga and anime, focusing on the avenging young boy who is known as the "Queen's Loyal Dog", Ciel Phantomhive and his curious, cat-loving, demon butler, Sebastian Michaelis.
I thought it was good because it gives a description of the main characters and their names - plus a short and not too revealing snippet of the story. I thought the genre was also an important feature. The template I would use would be:
A [genre] anime [and/or] manga, focusing on the live(s) of the [short description], [main character's name] and the [short dedcription], [main characters nane].
For another example, Full Metal Alchemist:
A shounen manga and anime, focusing on the lives and adventures of the brothers - a short, bad-tempered but alchemistically talented Edward Elric and his brother, a gracious, polite and loving young boy with a hardship beyond fair, Alphonse Elric.
Or Chobits, perhaps:
A seinen anime and manga focused on the farm-boy come Tokyo University Motosua and his encounter with a gorgeous and glowing personal computer robot, known as a 'persocom' named Chii.
I didn't really know how a should do them properly, so I thought I may as well discuss the idea. I don't mean for it to be sent in concrete, but just as a trial-and-error theory.