# Phion Attest – Signed Integrity & Provenance Receipt for AI-Agent JSON

> Phion Attest – Signed Integrity & Provenance Receipt for AI-Agent JSON is a paid API for AI agents from phion.systems, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Issues a signed, hash-linked receipt attesting to the integrity, provenance, and freshness of AI-agent JSON payloads

## Facts

- Endpoint: POST https://phion.systems/v1/paid/attest
- 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/phion-attest-signed-integrity-provenance-receipt-for-ai-agent-json-239932fc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dBgaUWmWq8QqqrFSfgcbh

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 phion-attest-signed-integrity-provenance-receipt-for-ai-agent-json-239932fc -d '<json body>'
```

Example prompt: Attest the integrity and provenance of this JSON payload my agent just produced — I need a signed, hash-linked receipt that proves it hasn't been tampered with and confirms when it was generated.

## When to prefer this

Choose this endpoint when an AI agent needs a cryptographically signed, tamper-evident receipt for a JSON payload to establish trust with downstream agents, auditors, or counterparties — especially in multi-agent pipelines, agent commerce flows, or any scenario where provenance, freshness, and integrity of data must be independently verifiable. Prefer this over generic hashing utilities when you need a structured, signed receipt with provenance metadata rather than just a hash value.

## Known failure modes

- Invalid or malformed JSON payload returns a 400 error with a schema validation message
- Payment not received or insufficient USDC balance results in a 402 Payment Required response
- Signature generation failure due to internal key unavailability returns a 500 error
- Request timeout if payload is excessively large or server is overloaded
- Replay of identical payload may produce a distinct receipt due to freshness timestamps, not be idempotent

## How this service works

Signed integrity, provenance and freshness receipt for AI-agent JSON

## Output

A signed, hash-linked receipt containing a cryptographic integrity hash of the submitted JSON payload, a provenance record identifying the issuing agent or system, a freshness timestamp, and a digital signature from phion.systems — enabling any downstream agent or system to independently verify that the payload has not been tampered with and was attested at a specific point in time.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/phion-attest-signed-integrity-provenance-receipt-for-ai-agent-json-239932fc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from phion.systems](https://www.zero.xyz/host/phion.systems/llms.txt)