# Rubric Protocol Hedera Supply Facts

> Rubric Protocol Hedera Supply Facts 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 HBAR total/circulating supply with a post-quantum ML-DSA-65 attestation ID anchoring the snapshot to Hedera HCS

## Facts

- Endpoint: GET https://rubric-protocol.com/v1/x402/hedera-facts/supply
- 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-supply-facts-4c7711a0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_uytPu0qPjg_bpkhT5JfAj

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-supply-facts-4c7711a0
```

Example prompt: Fetch the current HBAR supply from Rubric Protocol and give me the attested snapshot with its ML-DSA-65 attestation ID so I can include it as tamper-evident proof in my audit log.

## When to prefer this

Choose this endpoint when your agent or system needs cryptographically provable, tamper-evident HBAR supply data rather than simply a raw number from an unauthenticated source. It is ideal for compliance, audit trails, regulated DeFi applications, or any agent workflow where you must prove what data you acted on at a specific moment. Prefer it over generic blockchain explorers when post-quantum attestation and HCS anchoring are required.

## Known failure modes

- Payment not received or invalid x402 USDC payment header — returns 402 Payment Required
- Hedera mirror node temporarily unavailable — may return stale snapshot or 503 error
- Invalid request format — returns 400 with schema validation error
- Rate limiting exceeded — returns 429
- Network congestion causing delayed HCS anchoring — attestation ID may reference a slightly older sequence

## 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 containing the current HBAR total supply and/or circulating supply figures, a timestamp for when the snapshot was taken, and an ML-DSA-65 post-quantum attestation ID referencing the Hedera Consensus Service (HCS) sequence number that anchors the data tamper-evidently on-chain. This allows any downstream consumer to independently verify that the data has not been altered.

## 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-supply-facts-4c7711a0/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)