io.github.mccallar/cfr-mcp
US Code of Federal Regulations
Is the US Code of Federal Regulations MCP server down? No. It answered initialize and tools/list in the probe of 2026-10-30.
Look up, search, and track changes to the US Code of Federal Regulations (eCFR).
alive probed 2026-11-14 · unchanged since 2026-10-30
- Run it
- uvx cfr-mcp@0.2.2 (stdio, probed in a container with the network off)
- Host
- pypi.org
- Reports itself as
- cfr 0.2.2
- Capabilities
- prompts, resources, tools
- Instructions
- 122 characters
- Of a 1M window
- 0.2 % of a 1M context window
- Count
- 1.8k tokens in Claude Opus 5.5, exact, measured 2026-10-16. With the Claude Code prefix mcp__…__ on each tool name: 1.9k. The o200k_base estimate is 1.0k. Counted again when the tool definitions change. Method.
- Repository
- https://github.com/mccallar/cfr-mcp
- Registry
- active, updated 2026-08-29 · registry entry
Most expensive tools
The Claude column scales the o200k estimate of each tool by this server's ratio of exact to estimate, 1.78×.
| Tool | ≈ Claude tokens | o200k estimate | Share of this server |
|---|---|---|---|
| compare_versions | 407 | 228 | 22 % |
| search_regulations | 326 | 183 | 18 % |
| lookup_citation | 314 | 176 | 17 % |
| what_changed | 235 | 132 | 13 % |
| where_does_term_appear | 221 | 124 | 12 % |
Compare this server with others.
More servers
Other registry entries on pypi.org, the ones next to this name; all of them.
- io.github.mbk-dev/okama-mcp · needs args
- io.github.mbrionesalvarez/caddie-mcp · alive
- Power BI Analyst MCP io.github.mbrummerstedt/powerbi-analyst-mcp · crashed on start
- io.github.mcande21/thealgorithms-mcp · needs mcp<2
- Cost Guard MCP io.github.mcpsmiths/cost-guard-mcp · crashed on start
- io.github.mcpsmiths/tracehub-mcp · needs env
- Census (ACS by ZIP) io.github.mcpwright/census-mcp · alive
- EDGAR (SEC filings) io.github.mcpwright/edgar-mcp · alive
Servers that mention regulations or federal.
- GroundTruth - Environmental Records ai.agentlookups/groundtruth · alive
- CounterScript - Drug Price Benchmarks ai.agentlookups/counterscript · alive
- AI-Portal Enterprise GenAI Briefing ai.ai-portal/ai-portal · alive
- AwardCast Federal Contracts ai.awardcast/federal-contracts · alive
- ai.bizmoon/regulatory · alive
- Gov Relations ai.govrelations/govrelations · alive
- Jurisprudências.ai ai.jurisprudencias/case-law · needs auth
- RallyProp: SBIR, OTA & Federal Innovation Funding ai.rallyprop/gov-funding · needs auth
Badge for the README
The result of the latest probe, the tool count and the token cost. The feed has an entry for every probe that changed them.
A mail when this server changes
Stops answering, comes back, tool set or cost changes. One confirmation mail first, a stop link in every mail.
For the publisher
- The server answers initialize and tools/list. Nothing to fix.