# OnChain Diligence Preflight Payment Check

> OnChain Diligence Preflight Payment Check is a paid API for AI agents from mcp.onchaindiligence.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Evaluates a proposed payment against a caller-supplied policy and optional sanctions screening, returning ALLOW, REQUIRE_APPROVAL, or BLOCK with a signed verifiable receipt before execution.

## Facts

- Endpoint: POST https://mcp.onchaindiligence.com/x402/preflight-payment
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onchain-diligence-preflight-payment-check-609d7939
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TX5q-xwIlRwNHH8ZBw9ST

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 onchain-diligence-preflight-payment-check-609d7939 -d '<json body>'
```

Example prompt: Before sending 500 USDC to wallet 0xABC123..., run a preflight compliance check against my policy that blocks high-risk jurisdictions and screens for OFAC sanctions — I need a signed receipt showing the verdict.

## When to prefer this

Choose this endpoint when you need a pre-execution compliance gate for on-chain or x402 payments — specifically when you want caller-defined policy evaluation combined with sanctions screening and a signed, independently verifiable receipt. Prefer over generic wallet screening when you need the combined policy+sanctions verdict in a single signed artifact before committing to a transaction.

## Known failure modes

- Invalid or malformed wallet address returns a validation error
- Missing required policy fields cause a 400 bad request
- Chainalysis oracle unavailable may delay or fail sanctions screening
- Network timeout on the signing service causes a 503
- Invalid policy schema causes policy evaluation to fail with descriptive error

## How this service works

Evaluate a proposed payment against a structured, caller-supplied policy and optional recipient sanctions screening, before execution. Returns ALLOW, REQUIRE_APPROVAL, or BLOCK with reasons, plus a signed OCD PREFLIGHT receipt anyone can independently verify. Policy evaluation only: OCD never holds, moves, or authorizes funds. The wallet, PayBox, or x402 client independently authorizes execution afterward; an ALLOW here does not guarantee it will proceed.

## Output

Returns a structured verdict of ALLOW, REQUIRE_APPROVAL, or BLOCK along with the specific reasons for the decision, plus a cryptographically signed OCD PREFLIGHT receipt that any party can independently verify. The receipt serves as an auditable compliance record. Note: an ALLOW verdict is advisory only — OCD never holds or moves funds.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchain-diligence-preflight-payment-check-609d7939/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcp.onchaindiligence.com](https://www.zero.xyz/host/mcp.onchaindiligence.com/llms.txt)