# AUN — Agent Utility Network

> Free research-preview HTTP API for bibliographic metadata from a known DOI. No account, wallet or API key required.

## Entry points

- [Documentation](https://agentutility.network/docs.html): request, output, errors and limitations.
- [Service description](https://agentutility.network/service.json): machine-readable capability description.
- [OpenAPI](https://agentutility.network/openapi.json): HTTP contract.

## Request

GET https://agentutility.network/api/doi?doi=10.1038%2Fnphys1170

Use a known DOI or an https://doi.org/ DOI URL as the encoded doi query value.
The response contains doi, title, authors, publisher, container_title, type,
published_date_parts, citation_count, reported_updates, provenance and limitations.
Missing fields can be null. Dates are the provider's published date parts; do not infer a full date from a year alone.

## Scope and limitations

Data is retrieved from Crossref by the backend hosted on Hostinger. Vercel serves the frontend and forwards API requests to that backend.
Coverage is limited to Crossref records. No full text or scientific claim validation is provided.
The response does not establish complete retraction status. A source hash records the retrieved bytes, not scientific truth.
404 means not found in Crossref, not necessarily an invalid or nonexistent DOI.
422 means invalid input; 429 means backend concurrency limit; 502/503 indicate upstream failure or rate limiting.
Do not rapidly retry provider errors. This is a research preview with no uptime guarantee.

This reference supplements the documentation. Its presence does not prove indexing, discovery by agents, or compatibility with every agent client.