In light of the undercover agent trying to arrest someone in the park this afternoon- it's possible there will be door knocks.
Say “No, you cannot come in. I do not consent to a search.”

Say “No, I will not answer your questions.”

Do not sign anything you are given without seeking advice from a lawyer first.

Lying to police may result in criminal charges. The safest thing is to not engage with them at all.

If They Want to Conduct a Search:

If they do not have a search warrant:

Say, “I do not consent to a search.”
You may inform them that if they leave a card a lawyer may contact them. You can then ask them to leave, or you can simply close the door.

If they do have a warrant, you may ask them to slide it under the door or mail slot.
You may want to take a picture of the warrant and send it to a lawyer.
You can assert that you wish to consult with a lawyer before consenting to a search. This may not stop them from entering.

Before they enter, you may wish to shut down electronics, move anything you wish to keep private from plain sight, and close all doors. The warrant may not apply to the entire house.

Anything in plain sight that obviously appears illegal or evidence of a crime may be seized.

If They Have Come to Carry out an Arrest

They must have an arrest warrant signed by a judge that is no more than ten days old, specifying someone in this home.
Who is named? You are not required to confirm whether or not that person is present.

If the arrest occurs inside, police may more thoroughly search the area of the person arrested.

On the other hand, if the named person decides to surrender outside, it may limit or prevent a police search of the house.

And always remember: “I am going to remain silent. I want to speak to a lawyer.”

For a poster you can print and tape by your door: https://crimethinc.com/posters/when-the-police-knock-on-your-door-your-rights-and-options

And of course, if LE shows up at your door, call the NLG!