us-eli-mcp
MCP server for US law with verifiable citations. Five sources behind ten read-only tools:
- Congress.gov API - the federal legislative process: bills as they move through committees and floor votes.
- GovInfo API - enacted law text as published packages: US Code, Statutes at Large, CFR annual editions, Federal Register issues.
- Federal Register API - full-text search over 1,003,504 FR documents (1994-2026, live-verified 2026-07-07), including 8,513 presidential documents (1,550 executive orders). Keyless.
- CourtListener search API - full-text search over 8,294,123 court opinions (live-verified 2026-07-07). The headline value is STATE case law (California, New York, Texas, ...), which no federal source covers. Keyless, ~5 requests/min anonymous.
- eCFR API - the CURRENT Code of Federal Regulations: section-level full-text search over 412,846 sections plus per-section amendment history. Keyless.
What this is not
- State legislation (all 50 states) - see LegiScan, a free-tier aggregator (30,000 queries/month) not wrapped here.
- A federal case-law workhorse - for heavy federal case-law research the mature MIT-licensed wrappers (blakeox/courtlistener-mcp, john-walkoe/courtlistener_citations_mcp) remain the recommendation; the case-law tools here exist primarily for state courts. See SOURCES.md.
Tools
| Tool | Purpose |
|---|---|
us_search_bills | List bills by congress (e.g. 118) and type (hr, s, hres, ...) |
us_get_bill | Full detail + latest action for one bill |
us_list_code_packages | List GovInfo packages in a collection (USCODE, CFR, FR, STATUTE) |
us_get_code_package | Metadata + download links (PDF/XML/TXT) for one package |
us_search_federal_register | Full-text search over FR documents; filter rules, notices, executive orders |
us_get_federal_register_doc | One FR document with its official citation (e.g. 91 FR 41591) |
us_search_case_law | Full-text search over 8M+ opinions; court filter (e.g. cal, ny, scotus) |
us_get_case | One opinion cluster by cluster_id |
us_search_cfr_sections | Full-text search over the current CFR (eCFR) |
us_get_cfr_section_history | Amendment history of one CFR section (e.g. 15 CFR 744.3) |
Every response carries lex_uri (a resolvable API URL), human_readable_citation
(the official convention: "H.R. 1, 118th Congress", "91 FR 41591",
"People v. Miranda-Guerrero, 519 P.3d 1004 (California Supreme Court 2022)",
"15 CFR § 744.3") and source_url (the public page). Reporter citations are
taken verbatim from the source and never fabricated; when none exists the
docket number is used instead.
Install
pip install us-eli-mcp
Windows 11 with Smart App Control
Smart App Control blocks unsigned executables, which covers uvx.exe, pip.exe
and the us-eli-mcp.exe launcher that pip writes at install time. The python.exe and
py.exe from the python.org installer are signed by the Python Software
Foundation, so running the module through the interpreter works:
python -m pip install us-eli-mcp
python -m us_eli_mcp
pip.exe is blocked for the same reason, so install with python -m pip, not
pip install. If python is not on PATH, use the Windows launcher: py -3 -m us_eli_mcp.
{ "mcpServers": { "us-eli-mcp": { "command": "python", "args": ["-m", "us_eli_mcp"] } } }
Do not turn Smart App Control off to work around this - it cannot be re-enabled without reinstalling Windows.
Configuration
| Env var | Default |
|---|---|
US_ELI_API_KEY | DEMO_KEY (shared, low rate limit - get your own free key at api.congress.gov/sign-up) |
US_ELI_GOVINFO_API_KEY | reuses US_ELI_API_KEY (same api.data.gov key family) |
US_ELI_CACHE_DIR | ~/.matematic/cache/us-eli |
US_ELI_AUDIT_DIR | ~/.matematic/audit |
US_ELI_BASE_URL | https://api.congress.gov/v3 |
US_ELI_GOVINFO_BASE_URL | https://api.govinfo.gov |
US_ELI_FR_BASE_URL | https://www.federalregister.gov/api/v1 (keyless) |
US_ELI_COURTLISTENER_BASE_URL | https://www.courtlistener.com/api/rest/v4 (keyless) |
US_ELI_ECFR_BASE_URL | https://www.ecfr.gov/api (keyless) |
The Federal Register, CourtListener and eCFR tools need no key at all.
License
Apache-2.0 (code). Congress.gov, GovInfo, Federal Register and eCFR data are US government works (public domain). CourtListener data is provided by the Free Law Project.