# agent-exec /drift — API Drift Detection for x402 Venues

> agent-exec /drift — API Drift Detection for x402 Venues is a paid API for AI agents from agent-exec.448c.org, paid per call via x402, $0.0061/call, status unknown (last checked 2026-10-10).

Fetches a snapshot of a known x402 API marketplace venue and compares it against a stored baseline to detect changes (drift) in the live response.

## Facts

- Endpoint: POST https://agent-exec.448c.org/drift?utm_source=zero.xyz
- Price: $0.0061/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-exec-drift-api-drift-detection-for-x402-venues-1de263a4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9VF3exxEEh1dkBqzNTUgR

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 agent-exec-drift-api-drift-detection-for-x402-venues-1de263a4 -d '<json body>'
```

Example prompt: Check whether the clearedindex x402 venue has drifted from its baseline — fetch the current live response and compare it against the stored snapshot so I can see what changed.

## When to prefer this

Use this endpoint when you specifically need to detect drift or changes in one of the five pre-indexed x402 API venue snapshots (agentry, clearedindex, percall, verantis, x402-list). It is ideal for monitoring whether AI agent API marketplaces have updated their listings, changed status codes, or altered their response bodies since a known baseline. Prefer this over generic HTTP diff tools when operating within the x402 pay-per-use micropayment ecosystem with no account setup required.

## Known failure modes

- Invalid venue value — only agentry, clearedindex, percall, verantis, and x402-list are accepted; any other value returns a 400 or validation error
- Live fetch failure — t2 fields (body, sha256, http_status, content_type) may be null if the upstream venue URL is unreachable
- Payment not included or invalid — returns HTTP 402 requiring x402-compatible payment of 0.0061 USDC before the request is processed
- Venue URL redirected — t2 URL will reflect the final redirected URL, which may differ from the baseline t1 URL

## How this service works

Accountless, pay-per-use code execution for software agents: submit source code, get stdout, stderr and exit code back from an isolated, network-less sandbox. No account, no API key -- possession of valid payment is sufficient.

## Output

Returns two response objects: t1 (the archived baseline snapshot) and t2 (the freshly fetched live response), each containing the URL, HTTP status, content-type, body bytes, SHA-256 hash, raw body, and fetch timestamp. Also includes a list of diff events describing what changed between the two fetches, and the venue name.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "venue"
 ],
 "properties": {
  "venue": {
   "enum": [
    "agentry",
    "clearedindex",
    "percall",
    "verantis",
    "x402-list"
   ],
   "type": "string",
   "description": "One of the endpoints we already snapshot."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "venue",
  "t1",
  "t2",
  "events"
 ],
 "properties": {
  "t1": {
   "type": "object",
   "required": [
    "fetched_at",
    "url",
    "http_status",
    "content_type",
    "body_bytes",
    "body_sha256",
    "body"
   ],
   "properties": {
    "url": {
     "type": "string",
     "description": "The URL actually read. Always the baseline's recorded URL for t1; the final URL after any redirects for t2 (empty string if the live fetch never reached one)."
    },
    "body": {
     "type": [
      "string",
      "null"
     ],
     "description": "The raw body itself -- verify it yourself rather than trusting `events`. Null on t2 when the live fetch never reached a response."
    },
    "body_bytes": {
     "type": "integer",
     "description": "Bytes of body actually read and hashed."
    },
    "fetched_at": {
     "type": "string",
     "format": "date-time",
     "description": "When this side was observed -- the archived snapshot time for t1, or this request's own fetch time for t2."
    },
    "body_sha256": {
     "type": [
      "string",
      "null"
     ],
     "description": "sha256 of the body, hex-encoded, or null on t2 when the live fetch never reached a response."
    },
    "http_status": {
     "type": [
      "integer",
      "null"
     ],
     "description": "The HTTP status observed, or null on t2 when the live fetch never reached a response at all."
    },
    "content_type": {
     "type": [
      "string",
      "null"
     ],
     "description": "The Content-Type header observed, or null if none/never reached."
    }
   }
  },
  "t2": {
   "allOf": [
    {
     "type": "object",
     "required": [
      "fetched_at",
      "url",
      "http_status",
      "content_type",
      "body_bytes",
      "body_sha256",
      "body"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "The URL actually read. Always the baseline's recorded URL for t1; the final URL after any redirects for t2 (empty string if the live fetch never reached one)."
      },
      "body": {
       "type": [
        "string",
        "null"
       ],
       "description": "The raw body itself -- verify it yourself rather than trusting `events`. Null on t2 when the live fetch never reached a response."
      },
      "body_bytes": {
       "type": "integer",
       "description": "Bytes of body actually read and hashed."
      },
      "fetched_at": {
       "type": "string",
       "f
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-exec-drift-api-drift-detection-for-x402-venues-1de263a4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-exec.448c.org](https://www.zero.xyz/host/agent-exec.448c.org/llms.txt)