# GBLIN AI Action Receipt Sealer

> GBLIN AI Action Receipt Sealer is a paid API for AI agents from gblin.digital, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Seals SHA-256 hashes of an AI action's input and output into a signed, append-only transparency log, returning a portable Ed25519 receipt with RFC 6962 inclusion proof and a blockchain-anchored checkpoint.

## Facts

- Endpoint: POST https://gblin.digital/api/x402/seal
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gblin-ai-action-receipt-sealer-6a7797b7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__hx1snyjacTLCtJTtInPz

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 gblin-ai-action-receipt-sealer-6a7797b7 -d '<json body>'
```

Example prompt: Seal a receipt for the summarization action I just ran — input hash is 0xa3f1e2c4d5b6789012345678abcdef0123456789abcdef0123456789abcdef01, output hash is 0xdeadbeef1234567890abcdef1234567890abcdef1234567890abcdef12345678, label it 'document-summarization', agent is 'my-research-agent', and tool is 'gpt-4o'.

## When to prefer this

Choose this endpoint when you need a lightweight, cryptographically verifiable, tamper-evident record that a specific AI action occurred at a point in time — without needing a full compliance certificate. Ideal for agents that must prove provenance of outputs, create audit trails, or demonstrate that an input/output pair existed before a given timestamp. Prefer this over generic logging when you want a portable, offline-verifiable receipt anchored to a public blockchain.

## Known failure modes

- Invalid hash format (not 64 hex chars) returns validation error
- input_hash missing returns 400-level error
- Payment not included or insufficient USDC returns 402 Payment Required
- Log service unavailable returns 503
- meta field exceeds 512 chars returns rejection
- action label exceeds 128 chars returns rejection

## How this service works

AI Action Receipts: seal the HASHES of an AI action (input/output as hashes; your action label + meta are published) into GBLIN's signed append-only transparency log. Portable receipt: Ed25519 signature + RFC 6962 inclusion proof + C2SP signed checkpoint; root anchored daily on Base (EAS). Proves existence and time — not a compliance certificate. Free reads + demo: gblin-mcp.gblin-mcp-worker.workers.dev/log. Offline verifier: github.com/gblinproject/gblin-treasury-risk-regime

## Output

A portable cryptographic receipt containing an Ed25519 signature over the sealed hashes, an RFC 6962 Merkle inclusion proof placing the entry in the append-only transparency log, a C2SP signed checkpoint, and a reference to the daily root anchor recorded on Base via EAS. The action label, agent_id, tool, and meta fields are publicly published in the log.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "meta": {
   "type": "string",
   "maxLength": 512,
   "description": "Extra JSON object as a string (optional). PUBLISHED."
  },
  "tool": {
   "type": "string",
   "maxLength": 128,
   "description": "Tool or model used (optional). PUBLISHED."
  },
  "action": {
   "type": "string",
   "maxLength": 128,
   "description": "Short public label for what the AI did. PUBLISHED in the log: identifiers only, never secrets."
  },
  "agent_id": {
   "type": "string",
   "maxLength": 128,
   "description": "Your agent identifier (optional). PUBLISHED."
  },
  "input_hash": {
   "type": "string",
   "pattern": "^(0x)?[0-9a-fA-F]{64}$",
   "description": "sha256 of your input, 64 hex chars (0x prefix optional)"
  },
  "output_hash": {
   "type": "string",
   "pattern": "^((0x)?[0-9a-fA-F]{64})?$",
   "description": "sha256 of your output, 64 hex chars (optional)"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gblin-ai-action-receipt-sealer-6a7797b7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gblin.digital](https://www.zero.xyz/host/gblin.digital/llms.txt)