# SignalDesk AI – Europe PMC Search

> SignalDesk AI – Europe PMC Search is a paid API for AI agents from x402-agent.kariguetoazul.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-09).

Search the Europe PMC biomedical literature database and return structured article metadata including DOI, journal, authors, and open-access status.

## Facts

- Endpoint: GET https://x402-agent.kariguetoazul.workers.dev/api/research/europepmc-search?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-09
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signaldesk-ai-europe-pmc-search-12bf6e7c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TpBaKepituVs1JFlnKbb4

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 signaldesk-ai-europe-pmc-search-12bf6e7c
```

Example prompt: Search Europe PMC for the 5 most recent papers on mRNA vaccine delivery mechanisms and give me their titles, DOIs, and whether they're open access.

## When to prefer this

Choose this endpoint when you need structured bibliographic metadata from the Europe PMC / PubMed corpus for biomedical, genomics, or life science topics. It is preferable to generic web search when you need machine-readable DOIs, journal names, open-access flags, and author lists rather than free-text snippets. It is better than direct EBI API calls when you want a pay-per-use, pre-transformed response without managing API keys.

## Known failure modes

- Empty results if query is too specific or misspelled
- Payment failure (402) if USDC balance is insufficient
- Rate limiting or quota exhaustion under free tier
- Query exceeding 200-character limit returns validation error
- Network timeout if EBI upstream is slow
- Invalid limit value (outside 1–20) causes schema rejection

## How this service works

Evidence-backed autonomous AI jobs and paid data tools. Queue/D1/cron run outside the chat; free quotas and bounded execution apply.

## Output

Returns a JSON object with total match count, source metadata (provider, fetch time, expiry, source URL), and an array of article records each containing article ID, DOI, article URL, publication year, title, source type, authors, journal name, and open-access boolean.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "q"
     ],
     "properties": {
      "q": {
       "type": "string",
       "maxLength": 200,
       "minLength": 1,
       "description": "Search query."
      },
      "limit": {
       "type": "integer",
       "maximum": 20,
       "minimum": 1,
       "description": "Results, default 5."
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "total": 237208,
  "source": {
   "provider": "Europe PMC public metadata",
   "expires_at": "2026-10-02T10:44:49.750Z",
   "fetched_at": "2026-10-02T09:44:49.750Z",
   "source_url": "https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=CRISPR&format=json&pageSize=3",
   "transformed": true
  },
  "results": [
   {
    "id": "42771304",
    "doi": "10.1007/978-1-0716-5547-4_1",
    "url": "https://europepmc.org/article/MED/42771304",
    "year": "2027",
    "title": "CRISPR/Cas Systems: Biological Basis and Genome Editing Applications.",
    "source": "MED",
    "authors": "Cakiroglu E, Senturk S.",
    "journal": "Methods Mol Biol",
    "open_access": false
   },
   {
    "id": "42771314",
    "doi": "10.1007/978-1-0716-5547-4_11",
    "url": "https://europepmc.org/article/MED/42771314",
    "year": "2027",
    "title": "CRISPR/Cas9 Delivery Using Extracellular Vesicles.",
    "source": "MED",
    "authors": "Pečan P, Manček-Keber M.",
    "journal": "Methods Mol Biol",
    "open_access": false
   },
   {
    "id": "42771310",
    "doi": "10.1007/978-1-0716-5547-4_7",
    "url": "https://europepmc.org/article/MED/42771310",
    "year": "2027",
    "title": "Production of Lentiviral Vectors Encoding the CRISPR-Cas13d System for RNA Targeting.",
    "source": "MED",
    "authors": "Stilhano R, Martin L.",
    "journal": "Methods Mol Biol",
    "open_access": false
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signaldesk-ai-europe-pmc-search-12bf6e7c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-agent.kariguetoazul.workers.dev](https://www.zero.xyz/host/x402-agent.kariguetoazul.workers.dev/llms.txt)