# BIOS Literature Query API (x402)

> BIOS Literature Query API (x402) is a paid API for AI agents from x402.ai.bio.xyz, paid per call via x402, $0.015/call, status unknown (last checked 2026-09-14).

Queries the BIOS deep-research literature endpoint to retrieve AI-synthesized answers and cited references from scientific literature, paid via USDC micro-payment on Base.

## Facts

- Endpoint: POST https://x402.ai.bio.xyz/api/agents/literature/query
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bios-literature-query-api-x402-bbca365c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gLDnW3nHVFhFN0wwqcqA0

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 bios-literature-query-api-x402-bbca365c -d '<json body>'
```

Example prompt: Search the BIOS deep research literature database for what recent studies say about the role of gut microbiome in Parkinson's disease, and give me a synthesized answer with cited references.

## When to prefer this

Choose this endpoint when you need AI-synthesized answers grounded in real scientific literature with citations, specifically within the biomedical and life sciences domain. It is ideal over general-purpose web search when verifiability of sources matters, or when the query requires synthesis across multiple peer-reviewed papers. Prefer it over general LLM knowledge when you need up-to-date or niche scientific references. It suits agentic workflows that can handle async polling and crypto micro-payments via the x402 protocol on Base.

## Known failure modes

- Missing or invalid x402 PAYMENT-SIGNATURE header returns a 402 Payment Required error
- Payment window expiration causes conversation to enter timeout status, requiring a new payment to retrieve results
- Invalid or expired SIWX wallet signature on GET polling endpoint returns 401 Unauthorized
- Research job not yet completed returns a pending/in-progress status on polling
- Network or provider-side timeout for long-running deep research jobs
- Malformed query body returns 400 Bad Request

## How this service works

Payment proxy for the BIOS Deep Research API, powered by the x402 protocol.

This service wraps the BIOS deep-research endpoints with crypto micro-payments using USDC on Base. Payments are verified upfront but only settled once the research job completes.

## How it works

1. **Start a research job** — `POST /api/deep-research/start` with an x402 `PAYMENT-SIGNATURE` header. The payment is verified but not settled yet.
2. **Poll for results** — `GET /api/deep-research/{conversationId}` with an `X-SIWX` header (SIWE wallet signature). Only the wallet that paid can access results.
3. **On-demand settlement** — When polling a completed job, the payment is settled immediately and results returned. A background cron also handles batch settlement.
4. **Timeout handling** — If the payment window expires before completion, the conversation enters `timeout` status. A new payment is required to retrieve results.

## SIWX Authentication (Sign-In With X)

The `GET /api/deep-research/{conversationId}` endpoint requires wallet-based authentication via EIP-4361 (SIWE). When called without a valid `X-SIWX` header, the endpoint returns `401` with a SIWE challenge. The client must sign this challenge with the same wallet that made the original payment and resend the request.

The `X-SIWX` header is a base64-encoded JSON object: `{ "message": "<EIP-4361 message>", "signature": "0x..." }`.

## x402 Payment Protocol

All paid endpoints return `402 Payment Required` with a `PAYMENT-REQUIRED` header when no payment is provided. The header contains the payment requirements (price, token, network) that clients use to construct a payment.

See [x402 docs](https://docs.cdp.coinbase.com/x402/core-concepts/how-it-works) for details.

## Output

Returns a JSON object with a synthesized natural-language answer to the research question and an array of references, each containing a URL and title of the supporting scientific paper or source.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "answer": "Recent studies show...",
  "references": [
   {
    "url": "...",
    "title": "..."
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bios-literature-query-api-x402-bbca365c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.ai.bio.xyz](https://www.zero.xyz/host/x402.ai.bio.xyz/llms.txt)