Need help making an extension which automatically says gg in the chat when a game ends

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libclue

I'm a JS developer and I wanted to create a chrome extension which when a game ends, it says gg in the chat. 

Maybe I'll even add some cosmetic changes (which only shows to you, maybe I'll make it so it shows for everyone that uses the extension), such as being able to add a border to your profile and also so you can modify the layout of the website (such as moving the sidebar to the top, right or bottom and), which can be used for streaming.

Please let me know if this breaks TOS, I wanna make sure that I don't break the TOS, I just wanna make an extension which adds some cosmetics changes and that makes it say gg automatically.

Thanks.

libclue

???