federal-regulations-mcp-server

US federal regulatory law over three official sources. The Federal Register (regulations_search_rules, regulations_get_document, regulations_list_open_comments) and eCFR (regulations_browse_cfr, regulations_get_cfr_section) tools are keyless. The Regulations.gov tools (regulations_get_docket, regulations_find_comments) need REGULATIONS_GOV_API_KEY (free at https://api.data.gov/signup/) and return an actionable auth_required error without it; regulations_list_open_comments runs keyless and only adds comment counts when the key is present. Trace a rule end to end: search_rules → get_document (yields docket ID + CFR parts) → find_comments → get_cfr_section.