# Rubric Protocol Attested LLM Inference

> Rubric Protocol Attested LLM Inference is a paid API for AI agents from rubric-protocol.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Runs a GPT-4o-mini chat completion and returns the response paired with a post-quantum-signed, Hedera-anchored attestation binding the prompt hash, response hash, model version, and timestamp.

## Facts

- Endpoint: POST https://rubric-protocol.com/v1/x402/attested-inference
- 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/rubric-protocol-attested-llm-inference-2b4ac0c3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3ViZUv9D1obLyMB2DcdT7

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 rubric-protocol-attested-llm-inference-2b4ac0c3 -d '<json body>'
```

Example prompt: Run a GPT-4o-mini chat completion on this prompt — 'What are the key risks of deploying autonomous agents in financial workflows?' — and give me back the answer plus a post-quantum-signed, Hedera-anchored attestation so I have cryptographic proof of exactly which model version said what and when.

## When to prefer this

Choose this endpoint when the AI-generated output may later be questioned, audited, or used as evidence — such as in regulated industries (finance, healthcare, legal), autonomous agent workflows, or any context where proving which model said what and when is a compliance or liability requirement. Prefer it over a raw LLM API call whenever you need tamper-evident, post-quantum-signed, blockchain-anchored provenance rather than just an answer.

## Known failure modes

- Malformed or missing input payload returns a 400 error
- Payment not included or insufficient USDC triggers a 402 Payment Required response
- Hedera HCS anchoring latency or network issues may delay attestation finalization
- OpenAI API unavailability causes inference failure and a 503 response
- Invalid x402 payment header format results in payment rejection
- Rate limits or quota exhaustion on the underlying model returns an error

## How this service works

Attested LLM inference: gpt-4o-mini chat completion plus a post-quantum signed, Hedera-anchored attestation binding the 

## Output

Returns the GPT-4o-mini chat completion text alongside a structured attestation object containing the hashed prompt, hashed response, exact model version string, UTC timestamp, a post-quantum cryptographic signature, and a Hedera Consensus Service (HCS) sequence reference anchoring the attestation to the public ledger.

## 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"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "format": {
     "type": "string"
    },
    "example": {}
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rubric-protocol-attested-llm-inference-2b4ac0c3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from rubric-protocol.com](https://www.zero.xyz/host/rubric-protocol.com/llms.txt)