# AgentToolbox Quote Proof

> AgentToolbox Quote Proof is a paid API for AI agents from agnttoolbx.agenttoolbox2026.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-13).

Verifies that specific quotes appear accurately in given source URLs, returning proof of citation validity

## Facts

- Endpoint: POST https://agnttoolbx.agenttoolbox2026.workers.dev/v1/products/quote-proof/invoke?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agenttoolbox-quote-proof-866a77bd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-uPtIHNnCWWB2kCX0wTzO

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 agenttoolbox-quote-proof-866a77bd -d '<json body>'
```

Example prompt: Can you verify that this quote — 'The market grew 42% year over year' — actually appears in this article at https://example.com/report-2025 before I cite it in my report?

## When to prefer this

Use this endpoint when an AI agent needs to programmatically verify that specific quoted text actually appears in a given webpage before citing it — ideal for fact-checking pipelines, research assistants, journalism tools, and academic writing aids that need lightweight, per-call citation proof at low cost ($0.01 per call).

## Known failure modes

- URL is inaccessible or returns a non-200 status — verification fails for that source
- Quote not found in the page content — returns a mismatch or not-found result
- URL content is behind a paywall or login — endpoint cannot retrieve content to verify
- Malformed URL or URL exceeding max length — input validation error
- More than 5 URLs or 10 quotes submitted — request rejected with schema validation error
- Source index out of range (0-4) for a given quote — validation error
- Network timeout fetching the remote URL — returns an error for that source

## How this service works

Useful tools for agents. Small requests. Concrete results.

## Output

Returns a verification result indicating whether each provided quote was found in the corresponding source URL, along with proof or match details confirming citation accuracy or flagging discrepancies.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "required": [
    "urls",
    "quotes"
   ],
   "properties": {
    "urls": {
     "type": "array",
     "items": {
      "type": "string",
      "maxLength": 512
     },
     "maxItems": 5,
     "minItems": 1
    },
    "quotes": {
     "type": "array",
     "items": {
      "type": "object",
      "required": [
       "source_index",
       "quote"
      ],
      "properties": {
       "quote": {
        "type": "string",
        "maxLength": 512,
        "minLength": 1
       },
       "source_index": {
        "type": "integer",
        "maximum": 4,
        "minimum": 0
       }
      },
      "additionalProperties": false
     },
     "maxItems": 10,
     "minItems": 1
    }
   },
   "additionalProperties": false
  },
  "version": {
   "type": "string",
   "const": "0.1.0"
  },
  "agent_id": {
   "type": "string",
   "format": "uuid",
   "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
  },
  "quote_id": {
   "type": "string",
   "format": "uuid",
   "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
  },
  "prepared_id": {
   "type": "string",
   "format": "uuid",
   "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
  },
  "review_secret_hash": {
   "type": "string",
   "pattern": "^[0-9a-f]{64}$",
   "description": "Optional SHA-256 hex of caller-kept atbr_ secret (32 random bytes). Bound to this paid request; never send the raw secret here."
  },
  "payment_amount_atomic": {
   "type": "string",
   "pattern": "^(0|[1-9][0-9]{0,77})$",
   "description": "Canonical decimal USDC atomic-unit string (6 decimals). Protocol uint256 maximum 115792089237316195423570985008687907853269984665640564039457584007913129639935. No business maximum. Product minimum: 10000. Must equal the exact quoted/signed amount."
  },
  "max_charge_usdc_atomic": {
   "anyOf": [
    {
     "type": "string",
     "pattern": "^(0|[1-9][0-9]{0,77})$",
     "description": "Canonical decimal USDC atomic-unit string (6 decimals). Protocol uint256 maximum 11579208923731
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agenttoolbox-quote-proof-866a77bd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agnttoolbx.agenttoolbox2026.workers.dev](https://www.zero.xyz/host/agnttoolbx.agenttoolbox2026.workers.dev/llms.txt)