# Nomos Signed Decision Receipt

> Nomos Signed Decision Receipt is a paid API for AI agents from base-agent-preflight.bytoken2023.workers.dev, paid per call via x402, $2/call, status unknown (last checked 2026-09-14).

Creates a cryptographically signed, on-chain receipt attesting to an autonomous agent's decision, including risk assessment and evidence references.

## Facts

- Endpoint: POST https://base-agent-preflight.bytoken2023.workers.dev/x402/v1/evidence/signed-decision-receipt
- Price: $2/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/nomos-signed-decision-receipt-bbff699f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_unv1Laui5et9eI71ndnDj

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 nomos-signed-decision-receipt-bbff699f -d '<json body>'
```

Example prompt: Generate a signed decision receipt for my agent's decision 'Approved transfer of 500 USDC to wallet 0xABC' with evidence reference 'tx-hash:0x123def' so I have a tamper-proof audit record on Base.

## When to prefer this

Choose this endpoint when you need a cryptographically signed, on-chain attestation of an autonomous agent's decision for audit, compliance, or legal accountability purposes — particularly when you need a risk score and evidence reference bundled into one receipt on the Base network. Prefer this over generic logging when tamper-proof verifiability and blockchain anchoring are required.

## Known failure modes

- Missing or empty 'decision' field returns a validation error
- Missing 'evidence_references' may result in incomplete or rejected receipt
- Payment failure (x402) blocks the call before processing
- Malformed input JSON returns a 400-level error
- Network congestion on Base may delay finality of the signed receipt
- Duplicate submissions are not idempotent — each call produces a new receipt

## How this service works

Machine-payable service intelligence for discovering, verifying, and monitoring identity, risk, authorization, execution-preflight, and evidence APIs before autonomous agents spend.

## Output

Returns a JSON object containing the Base network identifier (eip155:8453), the product name ('nomos-signed-decision-receipt'), and an assessment object with a risk_score (numeric), risk_level (e.g. 'low'), and a flags array listing any risk signals — all cryptographically signed as an on-chain attestation of the submitted decision and evidence.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "decision": {
   "type": "string"
  },
  "evidence_references": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "network": "eip155:8453",
  "product": "nomos-signed-decision-receipt",
  "assessment": {
   "flags": [],
   "risk_level": "low",
   "risk_score": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nomos-signed-decision-receipt-bbff699f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from base-agent-preflight.bytoken2023.workers.dev](https://www.zero.xyz/host/base-agent-preflight.bytoken2023.workers.dev/llms.txt)