personal liability when signing a llc contract

are you personally liable if you sign just your name and not the llc

Answer

Like many things in the law, it depends.

A court will construe the contract to determine what the parties' intent was when the contract was signed.

Was it clear the parties intended for only the LLC to be liable on the contract, or for the owner to be liable as well?

The other side is going to argue that the intent was for you to be personally liable.

You'll argue the opposite.

The document, if there is no reference to the LLC on it, will be ambiguous.

Ambiguity + lawsuit = lots of money spent on lawyers.

It is best to have as unambiguous of written documents as possible. Therefore, contracts entered by the LLC should reference the LLC and the signature should state that you are signing in your capacity as member of XYZ, LLC and not personally.