# Frame Ancestors Check

> Frame Ancestors Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Validates whether a CSP frame-ancestors directive header contains a required source, returning a deterministic pass/advisory finding as versioned JSON.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/frame-ancestors-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/frame-ancestors-check-63b61460
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_f6qysbkdq0SNtANsaBEzt

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 frame-ancestors-check-63b61460 -d '<json body>'
```

Example prompt: Check whether the frame-ancestors CSP header "frame-ancestors 'self' https://example.com https://trusted.io" contains 'https://trusted.io' as a required source — I need a pass/fail finding before I cache this response.

## When to prefer this

Choose this endpoint when you need a lightweight, deterministic, stateless check of a CSP frame-ancestors directive against a specific required source — especially in agent pipelines that must validate web responses before caching, redirecting, or retrying. Prefer this over manual string parsing when you need a versioned, auditable finding with explicit pass/advisory status rather than raw boolean logic.

## Known failure modes

- Malformed or missing frame-ancestors header may yield an advisory/fail status rather than an error
- Required source string that doesn't match any listed source returns advisory status
- Header value exceeding 8192 characters may be rejected or truncated
- Non-CSP header strings passed as input may produce invalid parse results
- Payment failure via x402 results in request not being processed

## How this service works

Frame Ancestors Check: Frame Ancestors Check checks whether a CSP frame-ancestors directive contains a required source from bounded caller-supplied values without an external provider. Call Frame Ancestors Check before accepting, caching, redirecting, or retrying a caller-supplied web response. Returns normalized web evidence, the computed finding, and an explicit pass or advisory status for Frame Ancestors Check as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party,…

## Output

Returns versioned deterministic JSON containing: normalized web evidence (the parsed header and required source), the computed finding (whether the required source is present in the frame-ancestors directive), and an explicit pass or advisory status indicating compliance.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "header": {
   "type": "string",
   "maxLength": 8192,
   "description": "Header supplied to Frame Ancestors Check; used only for this bounded calculation and processed in memory without retention."
  },
  "required_source": {
   "type": "string",
   "maxLength": 8192,
   "description": "Required Source supplied to Frame Ancestors Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "source": "'none'",
   "present": true,
   "sources": [
    "'none'"
   ],
   "directive": "frame-ancestors"
  },
  "schema": "delx/util-frame-ancestors-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "87d66a2da893969f3b55da12bea54f3990c499fe4d58ef57b180b13ceeb775b2",
   "external_calls": 0
  },
  "operation": "web_reliability:frame_ancestors_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/frame-ancestors-check-63b61460/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)