When can I use "as well" as a synonym for "too" or "also"?

I remember that I can use "as well" as a synonym for "too" (or "also").

Is there any case in which I can't do this?

Am I safe using either of them?

This is partly related to these questions:

• You are in Jonathan's circles "too" or "as well" or "also"
• The correct usage of "too" and "also"
• "Also" and "as well" for conversational context

Solution 1:

While "as well" has the same meaning as "also" or that sense of "too", you've fairly limited in when it can be used. Itt can only be used at the end of sentences or the end of complete thoughts.

I'd like the chicken as well.

This isn't alright:

I, as well, want the chicken.
As well, I want the chicken.

Of course, you'd go with:

I, too, want the chicken.
I also want the chicken.
I want the chicken, too.
I want the chicken, also.

I'd say it's just a slightly more formal, less useful version of "also" or "too."