# AgentVerify Receipt Co-sign

> AgentVerify Receipt Co-sign is a paid API for AI agents from agentverify.t-horizon.co.za, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).

Co-signs a recorded commercial receipt to validate and finalize a transaction between autonomous agents

## Facts

- Endpoint: POST https://agentverify.t-horizon.co.za/v1/receipts/%7Breceipt_id%7D/cosign?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentverify-receipt-co-sign-57cefe8e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jqyVILTAaCawPzMMxRswy

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 agentverify-receipt-co-sign-57cefe8e -d '<json body>'
```

Example prompt: Co-sign receipt rcpt_abc123 on AgentVerify to confirm both parties have completed this commercial deal and mark it as verified.

## When to prefer this

Use this endpoint when two autonomous agents have completed a commercial interaction and need a mutually attested, tamper-evident record that both parties agree the transaction is complete. Prefer this over generic logging when you need a cryptographically anchored cosignature rather than a simple status update, and when interoperability with AgentVerify's trust-score system matters for downstream agent-to-agent trust checks.

## Known failure modes

- Receipt ID not found — 404 if the specified receipt_id does not exist
- Payment not provided or insufficient — 402 if the x402 USDC payment is missing or below $0.005
- Invalid HTTP method in body — validation error if method is not POST, PUT, or PATCH
- Malformed request body — 400 if required fields (type, method, bodyType, body) are missing
- Receipt already cosigned — may return conflict or no-op if cosigning is attempted twice
- Unauthorized — if the calling agent lacks valid credentials or trust standing to cosign

## How this service works

AgentVerify lets autonomous agents prove identity, record commercial dealings,
and check each other's trust before they transact.

Paid routes use the x402 protocol (HTTP 402, USDC on an EVM network). Set
`PAYMENTS_MODE=off` for local development. The server holds a receive-only
wallet address and an Ed25519 key used only to sign trust badges.

## Output

Returns a JSON object containing the receipt ID, an outcome status (e.g. 'completed'), and a boolean 'cosigned' field confirming whether the co-signature was successfully applied to the receipt.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {}
   }
  },
  "description": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "rcpt_example",
  "outcome": "completed",
  "cosigned": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentverify-receipt-co-sign-57cefe8e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentverify.t-horizon.co.za](https://www.zero.xyz/host/agentverify.t-horizon.co.za/llms.txt)