That wiki entry

cu chulainn (fate/grand order) wiki says "The same hero as Lancer from Fate/Stay Night."
but isn't that supposed to be a spoiler??

Not really - in the game, Servants' identites are revealed as soon as you get them, and don't factor so heavily into the story.

Plus, there are multiple Servants of each class... having them all be tagged after the class, caster_(fate/grand_order), wouldn't quite work.

As soon as I read Cu Chulainn I know who he is. The wiki is not as much of a spoiler as the tag itself.

Well yeah, I think I rather meant that. It's still a spoiler for those who haven't read fsn or played the game, isn't it?

I think it's an unavoidable spoiler.

Also how much of a spoiler is it really? I'm not familiar with how things transpire in the game, but going by the two anime he more or less rats himself out by episode 3 of the FSN anime and by episode 1 in the UBW TV anime when he uses his noble phantasm.

FSN Lancer's identity is revealed pretty much right away in everything that he's in afaik. Could be wrong. In FSN, rather than being a mystery, his identity being revealed causes an important event to happen.

In any case, he's one of the characters whose identities aren't a twist or spoiler in any way even if you know them.