You would disclose what you know, along with prior art. The company's patent attorney makes a call (along with applicable liabilities) whether it's patentable,

You would disclose what you know, along with prior art. The company's patent attorney makes a call (along with applicable liabilities) whether it's patentable, USPTO makes a call whether it's patentable, and maybe eventually the court makes a call whether it's a valid patent. You do your part (as part of the employment contract), but probably do not get to decide whether it's patentable or not.