# Qty Receipt — Deterministic Quantity Computation Receipt

> Qty Receipt — Deterministic Quantity Computation Receipt is a paid API for AI agents from qty.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-12).

Returns a cryptographically-hashed receipt document confirming the deterministic quantity conversions, formulas, and definitions computed in a Qty session

## Facts

- Endpoint: GET https://qty.vercel.app/v1/receipt?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/qty-receipt-deterministic-quantity-computation-receipt-fce5ba91
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RblQWaoWyn-td_hdrwe5Y

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 qty-receipt-deterministic-quantity-computation-receipt-fce5ba91
```

Example prompt: Pull the Qty receipt for the unit conversion I just ran at path /v1/convert so I can verify the SHA-256 hash and confirm the formulas used were deterministic.

## When to prefer this

Use this endpoint when you need a cryptographically verifiable, tamper-evident receipt of a deterministic quantity computation performed by the Qty service — especially for audit trails, compliance logging, or confirming that no numbers were hallucinated or invented. Prefer this over general-purpose computation APIs when the guarantee of determinism and the auditability of the result (via SHA-256) are requirements.

## Known failure modes

- Missing required 'path' or 'price' query parameter returns an error or empty receipt
- Invalid path that doesn't correspond to a prior computation returns an empty formulas/definitions array
- Requesting with an unsupported HTTP method (e.g. POST) returns a 405 error
- Network or upstream failure may return a non-200 status
- SHA-256 field may return all zeros if no computation has been recorded for the requested path

## How this service works

Qty converts known units for free and interprets messy quantities, prices, recipes, sizes, and dates in code. It never invents a number.

## Output

A JSON receipt document of kind 'qty.receipt.v1' containing a SHA-256 hash of the computation, an array of formulas applied, an array of definitions used, a timestamp, and a set of links to related resources (docs, MCP, OpenAPI, agent card, llms.txt). The hash allows downstream verification that the computation was deterministic and unmodified.

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "see": {
   "mcp": "/mcp",
   "docs": "/docs",
   "llms": "/llms.txt",
   "x402": "/.well-known/x402.json",
   "openapi": "/openapi.json",
   "llmsFull": "/llms-full.txt",
   "agentCard": "/.well-known/agent-card.json"
  },
  "sha256": "0000000000000000000000000000000000000000000000000000000000000000",
  "document": {
   "kind": "qty.receipt.v1",
   "formulas": [],
   "timestamp": "2026-10-05T00:00:00.000Z",
   "definitions": []
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/qty-receipt-deterministic-quantity-computation-receipt-fce5ba91/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from qty.vercel.app](https://www.zero.xyz/host/qty.vercel.app/llms.txt)