# Penny Engine — AI Agent Outcome Guard

> Penny Engine — AI Agent Outcome Guard is a paid API for AI agents from penny-paid-batch-production.up.railway.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-23).

Validates AI agent outputs and CSV catalog data against defined expectations, returning a deterministic PASS/FAIL verdict with a SHA-256 fingerprint for audit.

## Facts

- Endpoint: POST https://penny-paid-batch-production.up.railway.app/api/fulfill?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/penny-engine-ai-agent-outcome-guard-44dd6514
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zDitOTYxuC3KFrZiQRhvw

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 penny-engine-ai-agent-outcome-guard-44dd6514 -d '<json body>'
```

Example prompt: Run a batch QA check on these 5 agent job results against their expectations using the agent-output-batch-qa goal — I need a PASS or FAIL verdict and the SHA-256 fingerprint for the audit trail.

## When to prefer this

Choose this endpoint when you need a deterministic, cryptographically verifiable PASS/FAIL verdict on AI agent job outputs or CSV catalog data — especially in automated pipelines where auditability and fingerprinting matter. Prefer it over ad-hoc LLM-based evaluation when you need reproducible, machine-to-machine validation with a tamper-evident SHA-256 hash, or when you need to batch-QA up to 20 agent results in a single call for under a tenth of a cent.

## Known failure modes

- Invalid goal enum value causes rejection — must be exactly 'catalog-csv-audit' or 'agent-output-batch-qa'
- Jobs array below minItems (1) or above maxItems (20) triggers validation error
- Missing required job fields (id, result, expectations) cause schema rejection
- Malformed CSV string may produce unexpected audit failure
- Payment failure via x402 protocol blocks fulfillment
- Overly large or complex job objects may exceed processing limits

## How this service works

Machine-to-machine result validation via x402. One structured call, deterministic PASS or FAIL and SHA-256 fingerprint, $0.001 USDC on Base.

## Output

Returns a JSON object containing the goal type, a COMPLETED status, a SHA-256 fingerprint of the validated content, the number of workflow steps completed, and the service name. Each audited job or CSV batch receives a deterministic PASS or FAIL outcome backed by a cryptographic fingerprint for traceability.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "goal": {
   "enum": [
    "catalog-csv-audit",
    "agent-output-batch-qa"
   ],
   "type": "string"
  },
  "input": {
   "type": "object",
   "properties": {
    "csv": {
     "type": "string"
    },
    "jobs": {
     "type": "array",
     "items": {
      "type": "object",
      "required": [
       "id",
       "result",
       "expectations"
      ],
      "properties": {
       "id": {
        "type": "string"
       },
       "result": {},
       "expectations": {
        "type": "object"
       }
      }
     },
     "maxItems": 20,
     "minItems": 1
    },
    "targetMarginPct": {
     "type": "number"
    }
   }
  },
  "maxPriceUsd": {
   "type": "number"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "goal": "catalog-csv-audit",
  "status": "COMPLETED",
  "service": "M2M Unified Fulfillment",
  "evidence": {
   "algorithm": "SHA-256"
  },
  "workflow": {
   "stepsCompleted": 3
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/penny-engine-ai-agent-outcome-guard-44dd6514/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from penny-paid-batch-production.up.railway.app](https://www.zero.xyz/host/penny-paid-batch-production.up.railway.app/llms.txt)