Rule 11 sanctions
Penalties for filing papers that are frivolous, baseless, or filed for an improper purpose.
Federal Rule of Civil Procedure 11 requires that every filing be warranted by existing law (or a non-frivolous argument to change it) and have evidentiary support. Violations — including citing fabricated authority — can draw sanctions ranging from a reprimand to monetary penalties.
Rule 11 is the rule most directly implicated when AI hallucinated citations reach a court, which is why citation validation matters.