federal-regulations-mcp-server

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  <h1>@cyanheads/federal-regulations-mcp-server</h1>
  <p><b>Search and trace US federal rules across the Federal Register (proposed/final rules and notices), the eCFR (codified, point-in-time CFR full text, locally mirrored), and Regulations.gov (rulemaking dockets and public comments) via MCP. STDIO or Streamable HTTP.</b>
  <div>7 Tools • 2 Resources</div>
  </p>
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**Public Hosted Server:** [https://federal-regulations.caseyjhand.com/mcp](https://federal-regulations.caseyjhand.com/mcp)

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---

US administrative law is where agencies turn statutes into binding rules — and it spans three official sources that don't talk to each other. This server stitches them into one workflow: the **Federal Register** (the daily journal of proposed/final rules and notices), the **eCFR** (the codified Code of Federal Regulations, full text, point-in-time), and **Regulations.gov** (rulemaking dockets and the public comments filed on them). Every Federal Register document carries the docket ID and CFR-part handles that chain across sources, so a rule can be traced **proposal → comments → final → codified text** in one sequence.

The agent sees regulatory verbs — `search_rules`, `get_cfr_section`, `find_comments` — not three API clients. The Federal Register and eCFR tools are **keyless**; the two Regulations.gov tools need a free `api.data.gov` key and return an actionable error without it.

## Tools

Seven tools across the regulatory workflow. The **Federal Register** and **eCFR** tools (1–4, 7) are keyless. The two **Regulations.gov** tools (5–6) need `REGULATIONS_GOV_API_KEY`; `regulations_list_open_comments` runs keyless and only adds comment counts when the key is present.

| Tool | Source | Key | Description |
|:---|:---|:---|:---|
| `regulations_search_rules` | Federal Register | — | Search proposed rules, final rules, notices, and presidential documents by query, type, agency, date range, and open-for-comment status. The primary discovery entry point. |
| `regulations_get_document` | Federal Register | — | Fetch one FR document by number — full metadata plus the cross-source handles (docket ID, CFR parts, comment count) that chain into the comment and codified-text tools. |
| `regulations_browse_cfr` | eCFR | — | Walk the CFR hierarchy (structure mode) or full-text-search the codified CFR (search mode). Both feed `regulations_get_cfr_section`. |
| `regulations_get_cfr_section` | eCFR | — | Read the codified text at a CFR location — a section, a whole part, or an appendix — current or as of a past date. |
| `regulations_get_docket` | Regulations.gov | ✔ | Pull a rulemaking docket and the documents filed in it (NPRM, final rule, supporting materials). |
| `regulations_find_comments` | Regulations.gov | ✔ | Fetch public comments on a document or docket, or one comment's full body and attachments. Flags attachment-only submissions. |
| `regulations_list_open_comments` | Federal Register (+ Reg.gov enrich) | optional | Rules currently open for public comment, closing soonest first. Fully functional keyless; enriches comment counts when keyed. |

---

### `regulations_search_rules`

Search the Federal Register — the daily journal of US proposed rules, final rules, notices, and presidential documents (1994–present). Keyless.

- Full-text `query` across title and body, or browse by filters alone
- Filter by document `type` (`PRORULE`, `RULE`, `NOTICE`, `PRESDOCU`), `agencies` (Federal Register agency slug), and publication date window (`published_after` / `published_before`)
- Each result carries the `documentNumber`, `docketIds`, `regulationIdNumbers` (RIN), and `cfrReferences` that chain into the document, comment, and codified-text tools
- Pagination up to 100 per page, 50 pages; the Federal Register caps navigation at 5,000 records and the match count at 10,000 — when a result set is larger, the tool flags it and steers you to date-windowing

---

### `regulations_get_document`

Fetch one Federal Register document by its FR number — the stitching tool of this server. Keyless.

- Full metadata: title, type, agencies, abstract, action, effective/comment dates, RINs
- The output renders a **cross-source handles** block — the docket ID (→ `regulations_get_docket` / `regulations_find_comments`), affected CFR parts (→ `regulations_get_cfr_section`), and Regulations.gov document ID and comment count — each next to the tool name that consumes it
- `include_full_text` inlines the document body as plain text; default false returns the body URLs only (final rules can run tens of thousands of words)

---

### `regulations_browse_cfr`

Explore the codified Code of Federal Regulations via eCFR in two modes. Keyless.

- `structure` mode walks the CFR tree (all 50 titles, or one title's chapters → parts → sections) to discover a cite when the exact citation is unknown
- `search` mode runs a full-text query across the codified CFR and returns matching sections with their hierarchy path and a snippet
- `title` and `part` scope both modes, so a part surfaced by `structure` can be searched directly instead of filtering a whole title's hits by eye. A part needs its title in either mode — part numbers repeat across the Code — and is matched exactly, so pass it as eCFR writes it (`58`, not `Part 58` or `058`)
- A live search hit's `hierarchyPath` names the part it sits in (`Part 51 — Requirements for Preparation, Adoption, and Submittal of Implementation Plans`), so the subject matter is readable without a second call; a mirror hit's path stays structural, because the index stores no level names
- Search is served from the synced local mirror (FTS5) only when the mirror's title coverage can answer the request — a title it does not hold, an all-titles query against a scoped mirror, a `date`, or a cold deploy all go to the live eCFR search API instead
- Every search result reports `source` (`mirror` or `live`) and `sourceScope` — which corpus answered and what it covers, so an empty result is never mistaken for "no such regulation"
- `date` searches the section text in effect that day; eCFR indexes 2017-01-03 onward, and an undated search is pinned to eCFR's current index date rather than spanning every historical version
- Both modes assemble a `cfrCite` that feeds `regulations_get_cfr_section`, and both hand appendices back the same way: an `appendix` field with eCFR's verbatim identifier, and a cite that names the appendix rather than the part around it
- The mirror indexes section text only, so it never matches an appendix — its `sourceScope` says so, since otherwise an appendix that exists and one that does not both read as zero matches

---

### `regulations_get_cfr_section`

Read the codified text at a CFR location — one section, a whole part, or one appendix — via eCFR. Keyless.

- Answers "what does 40 CFR 50.1 say today?" and "...as of 2019-01-01?" — pass `date` for point-in-time text
- Provide `title` + `part` + `section` for one section, or omit `section` to fetch the whole part
- Provide `appendix` to read an appendix, passing the identifier verbatim as `regulations_browse_cfr` emits it (`Appendix A-1 to Part 50`, `Schedule I to Part 789`, `Special Federal Aviation Regulation No. 88`) — the identifiers are prose, not letters, and a short form matches nothing
- A whole-part read names the part's appendices and their headings but does not inline their text; appendices routinely run several times the length of the sections around them, so reading one is a deliberate second call
- Current single-section reads are served from the local mirror when ready (the `source` is reported); historical dates, whole-part fetches, appendix reads, and a cold mirror fall back to the live eCFR versioner
- The text carries what the XML carries: paragraphs, subheadings, editorial notes, tables (one pipe-delimited line per row), figure references, and the trailing source citation — the br