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Markedet Prompt-Injection Check
x402
Markedet Prompt-Injection Check is a paid API for AI agents from prompt-injection-check.onrender.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-29).
Analyzes web page content fetched from URLs for prompt injection attacks, returning per-URL verdicts, scores, and span-level evidence with intent classification.
Price / call$0.005
Success—
StatusUnknown
How this service works
Prompt-injection check for agents: per text a verdict (safe, suspicious, injection), a score, and per-span evidence with code point, UTF-8 byte and UTF-16 offsets plus intent (override, role_spoof, secret_request, bait_link, fake_order, fake_correction, hiding). Deterministic rules (mode fast) for English, with override and agent-addressed phrases also in Dutch and German; mode full adds an open DeBERTa classifier when the server has the model installed. Free self-test against a published, hashed known-answer set.
Output
Returns a results array with one object per URL containing: verdict (safe, suspicious, or injection), a numeric score, an array of spans with UTF-8/UTF-16 byte offsets and intent labels (override, role_spoof, secret_request, bait_link, fake_order, fake_correction, hiding), the page title, HTTP status, fetched and sanitized markdown, and fetch metadata. A summary object aggregates counts across all URLs.
Example use cases
Screen external URLs before agent ingestion
“I'm about to have you summarize these three pages: https://news-site.com/article1, https://news-site.com/article2, and https://blog.com/post. First, run a prompt-injection check on all of them with a threshold of 0.5 so I can see if any contain hidden instructions trying to manipulate you.”
Audit user-submitted links in a pipeline
“We've got a batch of user-submitted URLs — https://user-submission.com/doc1 and https://user-submission.com/doc2 — that our agent will process. Can you scan them for prompt injection with the fast mode and flag anything that comes back as suspicious or injection so we can block those before they reach the agent?”
Validate a vendor document for hidden overrides
“Before our procurement agent reads this vendor proposal at https://vendor-corp.com/proposal.pdf, check it for prompt injection — especially role-spoofing or fake-order intents — and give me the verdict, score, and any suspicious spans so I can decide whether to let the agent proceed.”
Technical details
Endpoint
POSThttps://prompt-injection-check.onrender.com/fetch-check?utm_source=zero.xyzWhen to prefer
Choose this endpoint when your AI agent needs to safely consume externally fetched web content and you need deterministic, span-level evidence of prompt injection attempts — not just a binary block/allow. It is especially valuable in agentic pipelines where user-supplied or third-party URLs are fetched before processing, where span offsets help downstream filtering, or where you need intent classification (role_spoof, fake_order, etc.) beyond a raw score. Prefer it over generic content moderation APIs when the threat model is specifically adversarial instructions embedded in documents targeting AI agents.
Side effects
- Non-HTTPS URLs are rejected by schema validation
- URLs that are unreachable or return non-200 status are marked failed in the summary
- Exceeding 10 URLs in a single call violates the maxItems constraint
- Model-dependent 'full' mode verdicts unavailable if DeBERTa model not installed on server
- Low threshold values may increase false-positive suspicious verdicts
- Payment failure via x402 prevents the call from completing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| urls | array | 1 to 10 public https URLs |
| threshold | number | |
| includeMarkdown | boolean | false leaves out the raw markdown and keeps only safe_markdown |
Output
Schema · Response
{
"type": "json",
"example": {
"results": [
{
"url": "https://example.com/",
"score": 0,
"spans": [],
"title": "Example Domain",
"status": "ok",
"charged": true,
"intents": [],
"verdict": "safe",
"markdown": "This domain is for use in documentation examples without needing permission. This is not a service; avoid relying on it for testing and monitoring purposes.",
"final_url": "https://example.com/",
"http_status": 200,
"human_summary": null,
"safe_markdown": "This domain is for use in documentation examples without needing permission. This is not a service; avoid relying on it for testing and monitoring purposes.",
"fetch_truncated": false,
"hidden_html_parts": 0,
"markdown_truncated": false
}
],
"summary": {
"ok": 1,
"safe": 1,
"urls": 1,
"failed": 0,
"injection": 0,
"suspicious": 0,
"charged_urls": 1
}
}
}Tags
x402
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