us-law-mcp

get_regulation_text

Read-onlyIdempotent

Retrieve the text of any U.S. CFR section or part, with point-in-time versions for past dates, including amendment history and authorizing statutes.

Instructions

Retrieve the text of a CFR section (or part-level metadata) from eCFR. Pass date=YYYY-MM-DD to get the version in force on that day — use this whenever the question concerns past conduct, because the current text may differ. Includes amendment history and the part's authorising statutes.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "get_regulation_text"
  }
}

Input Schema

Name	Required	Description
`date`	No	Point-in-time date (YYYY-MM-DD). Omit for the current text.
`full`	No	Return the complete text without eliding the middle.
`part`	No	Part number when you want part-level metadata, e.g. "261".
`title`	No	CFR title number, e.g. "40".
`section`	No	Section number, e.g. "261.11".
`citation`	No	Full citation, e.g. "40 CFR 261.11".
`includeHistory`	No	Include the amendment history for the section or part.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jul 31, 2026

TDQS

A4.2/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare read-only/idempotent, so description adds value by explaining date-based behavior and that history/authorising statutes are included. It does not contradict annotations, and the added context goes beyond what annotations convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two efficient sentences that front-load the core purpose, then give essential usage nuance. No redundant or filler content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only tool with rich schema and no output schema, the description covers the key scenarios (point-in-time, part metadata, history). It doesn't detail return format, but the annotation and schema fill most gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers 100% of parameters with descriptions. The description adds a use-case hint for the date parameter and clarifies the section vs. part distinction, but does not significantly expand on parameter semantics beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool retrieves CFR section text or part-level metadata from eCFR, using a specific verb and resource. It also mentions included extras (amendment history, authorising statutes) and is distinct from siblings like get_law_text.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit guidance: 'use this whenever the question concerns past conduct' due to potential differences from current text. While it doesn't name alternative tools, the when-to-use context is clear, and it distinguishes part-level from section retrieval.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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