US Codex MCP server
Featured official server
5 tools · Last check that passed 4 Nov 2026, 12:15 UTC
US Codex's own remote MCP server gives an agent search, full text, citations, history and release-to-release changes across US federal law: the United States Code, the Code of Federal Regulations, public laws, congressional bills and executive orders, with no sign-in. Once a day, Stackduke connects to it the way any MCP client would, with no account and no sign-in, and lists its tools. It never runs them.
All 5 tools
| Tool | Counted as |
|---|---|
compare | Changes things |
history | Changes things |
citations | Use not clear |
fetch | Said to only read |
search | Said to only read |
The tools the server listed at the last check that passed, at its default address and settings, with no sign-in; an account that signs in, or other settings, may see other tools. What a tool is counted as doing is Stackduke's cautious reading of the server's labels, the tool's name and its description: where they disagree it takes whichever says the tool can do most, so it overcounts on purpose. It does not say the server is safe, and it does not list what a tool cannot do. Descriptions are not shown, because they are written for models and may try to steer them.
Recent checks
21 of the last 21 checks passed
A check passes when the server lists its tools. Checked at https://uscodex.org/mcp.
Recent changes
No change seen across the last 21 checks that passed.
From the scan of 4 Nov 2026, 12:43 UTC. "Changed" and "Can do more" count changes from the last 30 days; older ones stay listed here. A change made and undone between two checks is not seen. Every check is in the scanner's public data.
Know when US Codex's tools change.
One email when US Codex's official MCP server adds, removes or changes tools, with what changed. Nothing else.
What to watch for
- US Codex is an independent project. It says it is not affiliated with, endorsed by or run by the US government, the House, the Office of the Law Revision Counsel or the National Archives. US Codex's data sources and coverage page
- Older public laws and bills, from the 104th to the 112th Congress for laws and the 103rd to the 112th for bills, are rebuilt from plain text, and US Codex labels them lower fidelity. US Codex's data sources and coverage page
- US Codex says its parsed editions may have imperfect nesting of subdivisions and flattened tables, and points to the official slip-law PDFs or the printed Statutes at Large for authoritative use. US Codex's data sources and coverage page
How to limit it
With US Codex's own settings, as its documentation describes them. Stackduke has not tested them.
- Check any citation the agent relies on against uscode.house.gov, ecfr.gov or govinfo.gov, as US Codex advises. US Codex's data sources and coverage page
- US Codex says no authentication, API keys or accounts are needed and that all its tools are read-only, so we recommend connecting it with no credentials. US Codex's MCP page
What Stackduke is designed to do
Stackduke is designed to sit between your agents and their MCP servers: to check each tool call against your rules before it runs, hold the risky ones for a person to approve, and keep a record of what was decided.
It does not yet forward or block tool calls for customers. Today it reads what this server offers and publishes what changes.