Ecfr MCP server

Which servers in the official MCP registry are Ecfr's own, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-15

← Back to Ecfr

Whose server it is

Registry nameio.ecfr/ecfrverified in the MCP registry

The registry name sits under ecfr.io. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-15

Stateanswerschecked 2026-10-15
Tools3
Server calls itselfecfr-mcp
Server version1.0.0
Protocol version2025-06-18

On 2026-10-15 the server answered initialize and tools/list without a sign-in. First answer in 213 ms.

Measured dailydaily checks: 1, the first on 2026-10-19

Answeredmeasuring1 of the 7 daily checks it takes to print a share
Median first answer286 ms
Space in an agent's context≈ 562 tokensthe definitions of all its tools (3), which an agent carries on every turn
Tool definitionsB · 89 of 100

Parameters without a description: in 2 of 3

Worth a look

None of the five warning signs in these definitions.

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The state of vendors' MCP servers: method and numbers →

Tools it offers3 tools · read 2026-10-15

search_regulations
Search current US CFR text or a citation such as 31 CFR 10.1. Returns snippets and legal/inline citations with ecfr.io links. Fetch matching regulations before quoting. For every regulatory claim or quotation, include the returned…
get_regulation
Retrieve regulation text and child links by canonical path returned by search, e.g. /Title-31/Section-10.1. Inspect dates and stale flags. Follow nextOffset until null for all text. For every regulatory claim or quotation, include the…
list_titles
List the CFR titles with source dates and canonical ecfr.io URLs. Browse children with get_regulation.

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "ecfr": {
      "type": "http",
      "url": "https://ecfr.io/mcp"
    }
  }
}

Other servers listed as Ecfr's

io.ecfr/uscodeanswers, 3 toolsverified in the MCP registry

OpenAPI spec

3 paths, read 2026-10-15. Open the spec ↗

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.