Contractor Tax Enforcement Act - Amends federal claims law to direct the head of any federal agency that administers either a loan or a loan guarantee program, or issues a request for proposals for a federal contract, to require each loan or guarantee applicant and each entity that submits a contract proposal to submit a form authorizing the Secretary of the Treasury to disclose to the head of the agency information on whether the applicant or prospective contractor has an outstanding debt under the Internal Revenue Code in delinquent status.