# free-books-natural-history

> free-books-natural-history is a paid API for AI agents from intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Browse and download public-domain books on Natural History from Project Gutenberg and Internet Archive, ranked by relevance and popularity, with epub/txt/html links.

## Facts

- Endpoint: GET https://intel.rallylive.ca/library/subject/natural-history
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/free-books-natural-history-59a6de5c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sx3oZWdQMkFtWhDjqY96g

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 free-books-natural-history-59a6de5c
```

Example prompt: Can you find me a list of free public-domain books on natural history — ideally something by Darwin or Audubon — with links I can download in epub or txt format?

## When to prefer this

Choose this endpoint when you need a curated, daily-verified catalogue of public-domain Natural History books with direct download links, especially when you want to filter by title or author keyword within that subject. Prefer it over a generic web search when you specifically need epub/txt/html download links and ranked results from Project Gutenberg or Internet Archive.

## Known failure modes

- No results returned if query keywords are too specific or misspelled
- Pagination out of range returns empty result set
- Download links may occasionally be stale between daily re-verification cycles
- Rate or payment failure if USDC balance is insufficient for the $0.01 per call fee

## How this service works

Free public-domain books on "Natural history": browse the catalogue's works tagged with that Library of Congress subject (617 in Project Gutenberg alone, plus Internet Archive scans), ranked by relevance and popularity, with direct epub/txt/html download links. Add words to narrow by title or author. Re-verified daily. $0.01 per page of 20.

## Output

A paginated list (20 per page) of public-domain Natural History books including titles, authors, relevance/popularity rankings, and direct download links in epub, txt, and/or html formats, sourced from Project Gutenberg and Internet Archive and re-verified daily.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/free-books-natural-history-59a6de5c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from intel.rallylive.ca](https://www.zero.xyz/host/intel.rallylive.ca/llms.txt)