US Federal Regulations (CFR)
Search eCFR & Federal Register. People also call this Rules Lookup, CFR Lookup, eCFR Search, Federal Register Search. The tool names below are unchanged, so an existing client keeps working.
Read a CFR or eCFR section, or search US federal regulations and the Federal Register. Ask "what does 21 CFR 11.10 say?", "which regulations mention respirator fit testing?" or "what has the FDA proposed on food dyes this year?".
US Federal Regulations reads two official United States sources directly: the Electronic Code of Federal Regulations (eCFR) for the current text of any section of the Code of Federal Regulations, and the Federal Register for the rules, proposed rules, notices and presidential documents the agencies publish each day. People also call it Rules Lookup.
Use it for regulatory compliance questions about FDA, OSHA, EPA, SEC, FTC or FAA rules when the text is in the CFR or the Federal Register. It does not cover state law, court decisions or other countries.
A section lookup returns the citation, heading, full text, statutory authority and amendment history of the section, with the date the eCFR is up to date as of and a link to the section. A very long section is cut and says so. A search returns the matching sections or documents with the agency, the publication date, the comment deadline and effective date where there is one, and the CFR parts a document changes.
This is general information, not legal advice. The eCFR is an unofficial edition kept up to date by the Office of the Federal Register; the legal text is the Federal Register and the annual CFR. A rule applies differently to each situation, so check the current official text and ask a qualified lawyer before you rely on it.
It covers United States federal regulations only: not state or local law, court decisions, statutes, other countries' rules or guidance documents that are not in the Federal Register.
It stores nothing about you: answers are cached for up to six hours (sections) or an hour (searches), and the only lasting record is a daily count of calls per tool.
Tools
get_cfr_section: Read an eCFR section (FDA, OSHA, EPA)search_cfr: Search federal regulations and compliancesearch_federal_register: Search the Federal Register and rulemakings
Use it for a CFR citation or a search across FDA, OSHA, EPA, SEC, FTC or FAA rules in the federal text. State law and court decisions are not covered.
The server is https://rules.openkrill.app/mcp and needs no key. Install steps: ChatGPT, Claude, Cursor, Pi.