Agencies make binding rules through a prescribed process, and participation in it shapes both the rule and any later challenge.

Notice. A proposed rule published with its terms or substance, the legal authority, and the data and methodology relied on. A final rule must be a logical outgrowth of the proposal; a substantially different final rule requires a fresh round.

Comment period. Interested persons may submit data, views and arguments. The agency must respond to significant comments in the final rule’s preamble; a failure to respond is a common ground for vacatur.

Building the record. A comment that raises an issue preserves it for judicial review; one that does not may be forfeited. Comments should include data, identify specific defects in the agency’s analysis, and propose alternatives the agency will then be obliged to address.

Exemptions. Interpretive rules, general statements of policy, and rules of agency procedure are exempt, as is action for which notice is impracticable, unnecessary or contrary to the public interest — a narrow good cause exception that agencies invoke and courts scrutinize.

Guidance documents are not binding and cannot be enforced as though they were, though in practice regulated parties often treat them as binding.

Challenges. Petitions for review go to specified courts within short statutory deadlines that are strictly enforced.