# Research Paper Search

> Research Paper Search is a paid API for AI agents from agent-search.centorprat.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).

Searches and merges academic papers across Google Scholar, arXiv, Crossref, OpenAlex, and Semantic Scholar in a single call, returning unified metadata with open-access PDF links.

## Facts

- Endpoint: POST https://agent-search.centorprat.workers.dev/papers?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/research-paper-search-809cb05b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_f26VCWEHL3X-gxLqzGVX2

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability research-paper-search-809cb05b -d '<json body>'
```

Example prompt: Search for the top 15 academic papers on transformer-based language models published from 2020 onward, and only include ones with a free PDF I can download.

## When to prefer this

Choose this endpoint when you need comprehensive academic paper search across multiple scholarly databases in a single API call at low cost ($0.01/call). It is preferable to querying arXiv, Semantic Scholar, or Crossref individually because it merges and deduplicates results by DOI/arXiv ID, provides citation counts, and surfaces open-access PDFs. Especially useful for literature reviews, research discovery, or any workflow requiring cross-database coverage with open-access filtering.

## Known failure modes

- No papers found for very niche or misspelled queries — returns empty papers array
- yearFrom set too recent may drastically reduce results for emerging topics
- openAccessOnly filter may return fewer results even when many papers exist
- numResults above 25 will be capped or rejected — max is 25
- Ambiguous short queries may return loosely related papers from cross-database merging
- Rate limiting or upstream source failures may return partial results

## How this service works

Academic paper search across Google Scholar, arXiv, Crossref, OpenAlex and Semantic Scholar in one call, merged by DOI / arXiv id / title: title, authors, year, venue, citation count, DOI, abstract, landing page and open-access PDF link. Ranked by relevance, citations and recency; yearFrom and openAccessOnly filters. Half the price of other paper search APIs.

## Output

Returns a JSON object containing the original query string and an array of paper objects, each with DOI, year, title, PDF URL, authors list, source databases (e.g. openalex, arxiv), and citation count. Results are deduplicated by DOI or arXiv ID and ranked by a combination of relevance, citation count, and recency.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "query": {
   "type": "string",
   "description": "topic or title"
  },
  "yearFrom": {
   "type": "integer",
   "description": "only papers from this year on"
  },
  "numResults": {
   "type": "integer",
   "description": "1-25 (default 10)"
  },
  "openAccessOnly": {
   "type": "boolean",
   "description": "only papers with a free PDF"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "query": "...",
  "papers": [
   {
    "doi": "...",
    "year": 2024,
    "title": "...",
    "pdfUrl": "https://...",
    "authors": [],
    "sources": [
     "openalex",
     "arxiv"
    ],
    "citations": 120
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/research-paper-search-809cb05b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-search.centorprat.workers.dev](https://www.zero.xyz/host/agent-search.centorprat.workers.dev/llms.txt)