# Rubric Protocol – Hedera Topic State (Attested)

> Rubric Protocol – Hedera Topic State (Attested) is a paid API for AI agents from rubric-protocol.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Returns the current state of a Hedera Consensus Service (HCS) topic, cryptographically attested with an ML-DSA-65 post-quantum signature anchored on Hedera mainnet.

## Facts

- Endpoint: GET https://rubric-protocol.com/v1/x402/hedera-facts/topic-state
- 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/rubric-protocol-hedera-topic-state-attested-de2d42ac
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_oGPQc6IqcurQGIgN_QfZG

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-hedera-topic-state-attested-de2d42ac
```

Example prompt: Fetch the current state of a Hedera Consensus Service topic for me — I need the sequence number, running hash, and a post-quantum ML-DSA-65 attestation I can reference to prove what the topic state was at this moment.

## When to prefer this

Use this endpoint when you need cryptographically attested, tamper-evident proof of a Hedera HCS topic's current state — especially in compliance, audit, or regulatory contexts where you must later prove what the topic state was at the exact moment an agent acted. Prefer over raw Hedera mirror node queries when post-quantum signature attestation (ML-DSA-65) and Hedera-anchored provenance are required.

## Known failure modes

- Topic ID not found or invalid – returns error indicating unrecognized HCS topic
- Hedera mirror node unavailable – may return stale or error response
- Payment not processed – x402 payment required before data is returned
- Attestation service degraded – signature generation may fail, returning partial or no attestation
- Rate limiting – too many requests in a short window

## How this service works

Attested Hedera network facts: HBAR exchange rate, gas fees, supply, node roster, throughput, topic state. Each response

## Output

A JSON snapshot of the requested Hedera HCS topic's current state, including sequence number, running hash, and any associated topic metadata, paired with an ML-DSA-65 attestation ID that serves as a tamper-evident, post-quantum-signed reference to the served data anchored on Hedera mainnet.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "fact"
     ],
     "properties": {
      "fact": {
       "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-hedera-topic-state-attested-de2d42ac/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)