Federal Rule Impact MCP Server

Answer "what regulations changed for this industry" from the US Federal Register — final rules, proposed rules and notices, searched by CFR title, agency, keyword and date, live.

Built for policy and compliance teams.

Three things this server gets right that a naive read gets wrong

Every one measured live against the source on 2026-07-30.

1. Keyword search is full-text over the whole document — it is not a topic filter

A 90-day search for cybersecurity returned 10 documents, and 10 of 10 had the word in neither the title nor the abstract. Among the hits:

Lamb Meat; Institution of Investigation, Scheduling of Public Hearing
Drawbridge Operation Regulation; Newark Bay, Between the Cities of ...
Privacy Act of 1974; System of Records

That is correct API behaviour — the term is matched somewhere in the document body — and it is useless as an industry filter if you assume otherwise. So every keyword answer reports how many hits actually carry the term where a human can see it, and points you at the structural filters instead.

The honest way to ask "what changed for my industry" is cfr_title or agency_slug. A CFR-title-21 query returned 54 final rules in 90 days, every one a drug or medical-device rule.

2. A bad agency slug is an HTTP 400, not an empty result

conditions[agencies][]=not-a-real-agency
  -> 400 {"errors":{"agencies":"invalid value"}}

One careless except away, that reads as "nothing changed for your industry" — the worst possible wrong answer for a compliance team. So slugs are validated against the API's own 472-agency list before the query is sent, an unrecognised slug comes back as a free notice with near-matches, and any non-200 raises rather than returning an empty list.

3. Effective dates are often missing, including on final rules

Measured: of 20 consecutive published rules, one carried no effective date, and a rule fetched individually also had effective_on: null. Publication date is always there; effective date is not. This server reports effective_date_known and never backfills one date from the other.

Tools

tool	what it answers
search_rules	What was published in a trailing window, filtered by CFR title, agency, type or keyword
get_rule	One document in full: agencies, CFR references, RINs, dockets, dates, abstract, URL
list_agencies	All 472 agency slugs the Register recognises, filterable
list_cfr_titles	The 50 CFR titles — the structural map from an industry to a filter
explain_limits	What this server will and will not say, and the three traps above. Read before acting.

Document types: rule, proposed_rule, notice, presidential_document. The default is rules plus proposed rules. An unrecognised type is refused, never silently defaulted.

Scope and compliance

US Federal Register only. State registers, agency guidance published outside the Register, and the text of the CFR itself are not covered.

federalregister.gov/robots.txt disallows the HTML search pages — /documents/search, /articles/search, /regulations/search, /public-inspection/search — and does not disallow /api/. This server uses the JSON API only; a test asserts no disallowed path can be built into a request URL. No Crawl-delay is stated and the API returns no rate-limit header, so pacing is our own choice: every call goes through one shared strict-pacing bucket at 5 requests/second.

This server reports what the Federal Register published. It does not determine that a rule applies to you, does not compute compliance deadlines, and is not legal advice.

Pricing

Event	Price
Server start (apify-actor-start)	$0.05, charged once per server run by the platform
Tool call (mcp-tool-call)	$0.05 flat per completed tool call

No other events. Memory is pinned to 1024 MB so the start fee is charged once — on this platform the start event bills once per gigabyte.

Errors and notices are not charged. An unknown agency slug, a CFR title outside 1–50, an unknown document type, or a Federal Register read failure returns without billing.

A sourced "nothing was published" IS charged, and so is "that document number is not in the Register" — those are the answers to the questions asked.

If a tool call cannot be billed correctly, the call fails rather than serving free.