# ForgeMesh Notary — AI Inference Attestation

> ForgeMesh Notary — AI Inference Attestation is a paid API for AI agents from notary.forgemesh.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Creates a cryptographic receipt for a single AI inference: an Ed25519-signed attestation, SHA-256 content hash, receipt token, and Merkle anchor status that proves an AI model produced a specific output.

## Facts

- Endpoint: POST https://notary.forgemesh.io/api/notarize
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/forgemesh-notary-ai-inference-attestation-cbd13914
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3svXz97h025ZeN8cC_a3z

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 forgemesh-notary-ai-inference-attestation-cbd13914 -d '<json body>'
```

Example prompt: Notarize this GPT-4o response for me — the prompt was 'Summarize the merger agreement' and the model output was 'The merger is valued at $2.4B with a 60-day close window'; use model ID openai/gpt-4o and timestamp 2025-06-10T14:32:00Z so I have a signed cryptographic receipt I can verify later.

## When to prefer this

Choose this endpoint when you need a single-inference cryptographic receipt with a human-readable receipt token and Merkle anchoring — ideal for one-off notarizations where auditability, legal defensibility, or public verifiability of a specific AI output is required. Use the sibling bulk endpoint for high-volume batch attestation. Prefer this over generic logging or timestamping services when the signed Ed25519 attestation and SHA-256 content hash are specifically needed to prove model identity and output integrity.

## Known failure modes

- Missing required fields (prompt or response absent) — returns 400 Bad Request
- Malformed model_id format — returns 400 with validation error
- Payload too large (metadata > 4 KB) — returns 413 or 400
- Payment failure (x402 micropayment not settled) — returns 402 Payment Required
- Invalid ISO-8601 client_timestamp format — returns 400
- Service unavailable or signing key error — returns 500
- Merkle anchor may be pending at time of response — anchor status returns 'pending' rather than confirmed

## How this service works

Notarize AI output: a signed Ed25519 attestation of the model response plus sha256 content hash, receipt token, and Merkle anchor status for one AI inference — a cryptographic receipt for inference that lets you prove an AI said X and verify model output authenticity, checkable free by anyone, anytime.

## Output

Returns an Ed25519-signed attestation object containing: a digital signature over the content, a SHA-256 hash of the prompt+response+model_id+timestamp bundle, a receipt token (unique identifier for this notarization), and a Merkle anchor status indicating whether the record has been anchored to a Merkle tree. The receipt is publicly verifiable by anyone at any time at no cost.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "prompt": {
   "type": "string",
   "description": "Exact prompt/input sent to the model"
  },
  "metadata": {
   "type": "object",
   "description": "Optional caller metadata, <= 4 KB — accepted but NOT persisted or hashed (reserved for future opt-in retention)"
  },
  "model_id": {
   "type": "string",
   "description": "Model identifier, e.g. openai/gpt-5 or claude-fable-5"
  },
  "response": {
   "type": "string",
   "description": "Exact model output being notarized"
  },
  "client_timestamp": {
   "type": "string",
   "description": "ISO-8601 time the inference ran (optional; included in the content hash)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "anchor": {
   "status": "pending"
  },
  "model_id": "openai/gpt-5",
  "algorithm": "ed25519",
  "signature": "base64-ed25519-signature",
  "receipt_url": "https://notary.forgemesh.io/api/receipt/att_0123456789abcdef01234567",
  "content_hash": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
  "notarized_at": "2026-07-03T12:00:01.000Z",
  "receipt_token": "private-receipt-token",
  "signer_pubkey": "base64-ed25519-public-key",
  "attestation_id": "att_0123456789abcdef01234567",
  "payload_stored": false,
  "client_timestamp": "2026-07-03T12:00:00Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/forgemesh-notary-ai-inference-attestation-cbd13914/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from notary.forgemesh.io](https://www.zero.xyz/host/notary.forgemesh.io/llms.txt)