# x402stock Patent Application Assignments Lookup

> x402stock Patent Application Assignments Lookup is a paid API for AI agents from agents.x402stock.xyz, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Retrieves assignment history and ownership transfer records for a given US patent application number

## Facts

- Endpoint: GET https://agents.x402stock.xyz/api/v1/patent/%7Bapplication%7D/assignments
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402stock-patent-application-assignments-lookup-7803e880
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RjFhqgoGMquYQqtqq6l2v

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 x402stock-patent-application-assignments-lookup-7803e880
```

Example prompt: Can you pull up the assignment history for US patent application 16/123456 — I need to know who originally filed it and who owns it now?

## When to prefer this

Use this endpoint when you need structured patent assignment and ownership chain data for a specific US patent application number, especially for IP due diligence, legal research, or ownership verification. Prefer this over manual USPTO searches when operating in an automated agent pipeline that can pay per request in USDC without managing API credentials.

## Known failure modes

- Unknown or invalid patent application number returns empty results or 404
- Application number formatting errors (missing leading zeros, wrong format) cause lookup failures
- Newly filed applications may not yet have assignment records
- Network or payment authorization failure returns 402 or 5xx error

## How this service works

Market and economic data for AI agents — US stocks, ETFs and options, forex, crypto and on-chain perps, energy commodities (crude, natural gas, gasoline), US and global macro (Fed funds, CPI/PCE, jobs, GDP, Treasury debt & yields, World Bank indicators), SEC filings, congressional trades, and market sentiment. No API keys, no accounts. Pay per request in USDC via x402 or MPP. This server is a pay-per-use, transparent proxy in front of x402stock's own API: it handles identity, payment, and proxying. Agents can purchase autonomously or with their human's approval. This document is the source of truth for agents: it lists the complete verified paid surface with each operation's live price in its x-payment-info. Endpoints not listed here are not part of the supported catalog. The live catalog at /manifest.json is authoritative for prices and any free included units (prices[].includedUnits) - some meters include free usage per account before any charge.

## Output

Returns assignment records for the specified US patent application, including assignor names, assignee names, assignment dates, conveyance types (e.g. assignment, security interest, merger), and reel/frame reference numbers as recorded with the USPTO.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402stock-patent-application-assignments-lookup-7803e880/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agents.x402stock.xyz](https://www.zero.xyz/host/agents.x402stock.xyz/llms.txt)