Is it a scam for an agent to apply for a patent? Are there any examples of being cheated, such as the leakage of the agency.

It is more reliable to find those patent agencies officially registered in China National Intellectual Property Administration to apply for patents on their behalf. They have passed the formal examination and obtained the practice qualification, and are supervised by the intellectual property management department. If something is cheated or leaked, you can also go to the intellectual property office of the city to complain. Those cheated examples are generally done by some black agents who do not have the qualification of agency and have no fixed business place. Please contact the intellectual property office of your local city, and they will introduce you to a regular local agency.