# US Federal Regulations (CFR)

Read US federal regulations and new proposals in the Federal Register. It is free, with no sign-up and no key.

Also known as: Rules Lookup, CFR Lookup, eCFR Search, Federal Register Search.

## What it does

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.

- Reads the current text of any section of the US Code of Federal Regulations (eCFR)
- Shows a section's heading, statutory authority and amendment history with a link
- Searches eCFR text and federal compliance rules by words, in one title or all of them
- Searches the Federal Register for rules, proposed rules, notices, rulemakings and executive orders
- Shows comment deadlines, effective dates and the CFR parts a document changes

## Who it is for

Anyone who asks an AI assistant a question like this one: “What does 21 CFR 11.10 say?”

Roles that use it at work: Compliance reader, Editor.

Role guides that use it: [Compliance reader](https://tools.openkrill.app/for/compliance-reader).

## Price

US Federal Regulations (CFR) is free to use. There is no sign-up, no account and no API key. Calls are limited to 60 calls a minute per network and 5000 calls a day per server, shared by all callers. Repeat questions are answered from a cache.

## Tools it offers

- `get_cfr_section`: Read an eCFR section (FDA, OSHA, EPA)
- `search_cfr`: Search federal regulations and compliance
- `search_federal_register`: Search the Federal Register and rulemakings

## Connect

The MCP server is `https://rules.openkrill.app/mcp` (streamable HTTP). It needs no key.

Claude Code, in one command:

```
claude mcp add --transport http rules https://rules.openkrill.app/mcp
```

Hermes Agent, in one command that answers its two setup questions (no key, enable all tools):

```
printf 'n\ny\n' | hermes mcp add rules --url https://rules.openkrill.app/mcp
```

Or add these lines to `~/.hermes/config.yaml`, under an existing `mcp_servers:` key if the file has one. Start a new Hermes session after either step.

```
mcp_servers:
  rules:
    url: https://rules.openkrill.app/mcp
```

Any other agent: give it this page's Markdown address, `https://tools.openkrill.app/tools/rules.md`, and ask it to connect US Federal Regulations (CFR).

Install guides, each checked with a real call: [US Federal Regulations (CFR) in ChatGPT](https://tools.openkrill.app/integrations/rules/chatgpt), [US Federal Regulations (CFR) in Claude](https://tools.openkrill.app/integrations/rules/claude), [US Federal Regulations (CFR) in Cursor](https://tools.openkrill.app/integrations/rules/cursor), [US Federal Regulations (CFR) in VS Code](https://tools.openkrill.app/integrations/rules/vscode), [US Federal Regulations (CFR) in Pi](https://tools.openkrill.app/integrations/rules/pi).

## Job recipes for agents

Step-by-step recipes that walk an agent through 3 jobs with this server's tools:

- Read an eCFR section (FDA, OSHA, EPA), with `get_cfr_section`
- Search federal regulations and compliance, with `search_cfr`
- Search the Federal Register and rulemakings, with `search_federal_register`

[Download the recipes as SKILL.md](https://tools.openkrill.app/skills/rules-jobs/SKILL.md). Save it as `rules-jobs/SKILL.md` in your agent's skills folder. A connected MCP client gets the same recipes from `prompts/list` on the gateway, `https://api.openkrill.app/gateway/mcp`.

It is listed under Research and public facts in the [full tool list](https://tools.openkrill.app/tools). The same facts in plain text are in [llms.txt](https://tools.openkrill.app/llms.txt).

Source: the US Federal Regulations (CFR) listing, version 1.1.0. As of 2026-10-18.