# VEA /attest — Post-Execution AI Transaction Attestation

> VEA /attest — Post-Execution AI Transaction Attestation is a paid API for AI agents from vea-base.onrender.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Verifies after blockchain execution that the on-chain outcome exactly matched the originally declared intent, returning a signed attestation.

## Facts

- Endpoint: POST https://vea-base.onrender.com/attest
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/vea-attest-post-execution-ai-transaction-attestation-a965941b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xOz6ZNKEAcqJvgdt3tljy

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 vea-attest-post-execution-ai-transaction-attestation-a965941b -d '<json body>'
```

Example prompt: After my agent just submitted that USDC transfer transaction on Base, run a post-execution attestation against the original intent I declared — check whether what actually happened on-chain matches what was approved, and give me a signed receipt of the result.

## When to prefer this

Use this endpoint when you need a cryptographically signed, non-custodial post-execution audit confirming an AI agent's blockchain transaction matched its pre-approved intent. Prefer VEA /attest over manual on-chain log inspection when you need a structured, signed receipt for compliance, audit trails, or chained agent workflows where trust verification between steps is required. It is especially valuable in autonomous agent pipelines where no human reviews individual transactions.

## Known failure modes

- Mismatch between intent and execution objects causes a denial/fail attestation result
- Malformed or missing intent or execution fields return a 400-level validation error
- If the execution object does not reference a verifiable on-chain event, attestation may be inconclusive
- Payment not fulfilled via x402 protocol results in 402 Payment Required before processing

## How this service works

Two calls. /verify runs BEFORE signing: allow or deny plus an Ed25519-signed receipt. /attest runs AFTER execution: did the chain do exactly what was declared? Non-custodial — VEA holds no keys and never executes. Paid per call over x402; the documented samples under /samples are free and use the same engine.

## Output

Returns a verdict indicating whether the actual on-chain execution matched the declared intent (allow/deny style match result), along with an Ed25519-signed attestation receipt that can be stored as a tamper-evident proof of the post-execution check.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "intent",
  "execution"
 ],
 "properties": {
  "intent": {
   "type": "object"
  },
  "execution": {
   "type": "object"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/vea-attest-post-execution-ai-transaction-attestation-a965941b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from vea-base.onrender.com](https://www.zero.xyz/host/vea-base.onrender.com/llms.txt)