# Synthex Forge Output Verification

> Synthex Forge Output Verification is a paid API for AI agents from x402.synthexforge.com, paid per call via x402, $0.5/call, status unknown (last checked 2026-10-21).

Verifies an AI-generated output against a declared schema, claimed value, and accuracy budget, returning an Ed25519-signed attestation artifact on Base mainnet via x402 micropayment.

## Facts

- Endpoint: POST https://x402.synthexforge.com/v1/output/verify?utm_source=zero.xyz
- Price: $0.5/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synthex-forge-output-verification-688df9b3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ci_qBLh2zjKlWeX5YQlYU

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 synthex-forge-output-verification-688df9b3 -d '<json body>'
```

Example prompt: Can you verify that this AI-generated report output matches its declared JSON schema, check that the claimed accuracy is within 5%, and give me a signed attestation artifact — the subject is 'financial-summary-Q1', staleness budget is 3600 seconds?

## When to prefer this

Choose this endpoint when you need a cryptographically verifiable, signed attestation that an AI-generated output conforms to a declared schema and claimed values — especially for governance, compliance, or audit trails. It is uniquely suited for workflows requiring on-chain-anchored artifacts (Base mainnet) with staleness and accuracy budget enforcement. Prefer it over generic validation services when you need Ed25519-signed, SHA-256-hashed proof suitable for downstream verification pipelines.

## Known failure modes

- 402 Payment Required — x402 payment envelope must be resolved before the endpoint returns a result
- Output fails schema validation — mismatch between output content and declared schema returns a failed attestation
- Staleness budget exceeded — output timestamp is older than stalenessBudgetSeconds, returns a freshness failure
- Claimed value mismatch — accuracy checks reveal the claimed value diverges beyond the accuracy threshold
- Invalid input format — missing required fields such as output or schema returns a 400 error
- Ed25519 signing failure — internal key management issue prevents artifact generation

## How this service works

Synthex Forge x402 Receive: 41 paid verification, attestation and governance endpoints (Ed25519 + SHA-256 signed artifacts) plus free verify/public-key/standard sibling routes. Paid routes answer HTTP 402 with an x402 v2 `payment-required` envelope (atomic USDC on Base mainnet, chain ID 8453). Free routes are declared with `security: []` per the x402scan discovery spec.

## Output

A cryptographically signed verification response containing an Ed25519-signed, SHA-256-hashed attestation artifact indicating whether the output passed all declared checks (schema conformance, claimed value accuracy, staleness budget). The artifact is anchored to Base mainnet (chain ID 8453) via an x402 v2 micropayment of $0.50 USDC and is suitable for governance and compliance workflows.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "checks": {
   "type": "string"
  },
  "output": {
   "type": "string"
  },
  "schema": {
   "type": "string"
  },
  "claimed": {
   "type": "string"
  },
  "subject": {
   "type": "string"
  },
  "accuracy": {
   "type": "string"
  },
  "stalenessBudgetSeconds": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synthex-forge-output-verification-688df9b3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.synthexforge.com](https://www.zero.xyz/host/x402.synthexforge.com/llms.txt)