# Portable Observability Audit

> Portable Observability Audit is a paid API for AI agents from phion.systems, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).

Validates and cryptographically signs a portable event hash chain to establish tamper-evident audit trails for agent activity

## Facts

- Endpoint: POST https://phion.systems/v1/paid/trust/portable-observability-audit
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/portable-observability-audit-59dc59fc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jKT1_dGxCDQH70RGk3uiq

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 portable-observability-audit-59dc59fc -d '<json body>'
```

Example prompt: Can you validate and sign the event hash chain from our agent's latest run so we have a tamper-evident audit record we can share with our compliance team?

## When to prefer this

Choose this endpoint when you need cryptographic assurance that a sequence of agent events has not been altered — especially for compliance, cross-system handoffs, or sharing observability data with third parties who need independent verification. It complements phion.systems' broader agent trust suite (task handoff receipts, context provenance labeling) and is best suited when portability and signed attestation are requirements, not just logging.

## Known failure modes

- Invalid or malformed hash chain input returns a validation failure with details on the inconsistency
- Hash chain with detected gaps or tampering is rejected with an integrity violation error
- Missing required fields in the event payload result in a schema validation error
- Network or signing service unavailability returns a 5xx error
- Malformed JSON input returns a 400 bad request

## How this service works

Validate and sign a portable event hash chain

## Output

Returns a validation result confirming the hash chain's integrity along with a cryptographic signature attesting to its authenticity, forming a portable, tamper-evident audit certificate that can be shared or archived.

## 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/portable-observability-audit-59dc59fc/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)