# Regulus

> Source-first United States pipeline and hazardous-materials regulatory research.

Regulus provides regulations, PHMSA guidance and interpretations, inspections, enforcement records, incidents, rulemaking materials, NTSB records, and state pipeline-safety sources. Search results are discovery aids; retrieve primary documents before reaching a regulatory conclusion.

## Preferred access

- [MCP server](https://regulus.evalyn.ai/mcp): Preferred Streamable HTTP interface with six read-only research tools.
- [LLM API guide](https://regulus.evalyn.ai/api/llm): Markdown fallback for clients without MCP support.
- [OpenAPI description](https://regulus.evalyn.ai/openapi.json): Machine-readable fallback API contract.
- [Full agent guide](https://regulus.evalyn.ai/llms-full.txt): Research workflow, endpoint limits, and citation policy.
- [Agent Skill](https://regulus.evalyn.ai/SKILL.md): Installable regulatory-research workflow following the Agent Skills specification.

## Public read-only GET API

No authentication, cookies, or JavaScript are required.

- Search: GET https://regulus.evalyn.ai/api/llm/search?q={query}&limit={1-25}&mode={fast|smart}
- Document: GET https://regulus.evalyn.ai/api/llm/document?identifier={document-id-or-slug}
- Stable document JSON: GET https://regulus.evalyn.ai/document/{slug}.json
- Stable document Markdown: GET https://regulus.evalyn.ai/document/{slug}.md
- Passages: GET https://regulus.evalyn.ai/api/llm/passages?identifier={document-id-or-slug}&q={query}
- Related documents: GET https://regulus.evalyn.ai/api/llm/related?identifier={document-id-or-slug}
- Document hierarchy: GET https://regulus.evalyn.ai/api/llm/hierarchy?identifier={document-id-or-slug}
- Service status: GET https://regulus.evalyn.ai/api/llm/status

Example: https://regulus.evalyn.ai/api/llm/search?q=pressure+testing&limit=10

## Human-facing pages

- [Search](https://regulus.evalyn.ai/): Search the regulatory corpus.
- [Coverage](https://regulus.evalyn.ai/coverage): Inspect source and jurisdiction coverage.
- [Updates](https://regulus.evalyn.ai/updates): Review recent regulatory changes.
- [Timeline](https://regulus.evalyn.ai/timeline): Explore regulatory events over time.

## Citation rules

- Cite the official source_url and include the Regulus app_url when available.
- Do not infer a legal requirement from a search excerpt alone.
- Distinguish binding regulations from guidance, interpretations, inspections, enforcement records, and incident evidence.
- Verify effective dates, status, hierarchy, and related authority before answering applicability questions.

## Optional

- [Robots policy](https://regulus.evalyn.ai/robots.txt): Standards-based crawler access policy.
- [Sitemap](https://regulus.evalyn.ai/sitemap.xml): Index of stable public entry points.