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aiskills402 Prompt Injection Guard (File)
x402
aiskills402 Prompt Injection Guard (File) is a paid API for AI agents from api.aiskills402.com, paid per call via x402, $0.07/call, status unknown (last checked 2026-10-12).
Fetches and sanitizes content from a file URL, instructing an AI agent to treat retrieved content as data only and never as executable instructions, while reporting any injection attempts found.
Price / call$0.07
Success—
StatusUnknown
How this service works
Prompt Injection Guard: Keeps an AI agent from obeying instructions hidden in what it reads (indirect prompt injection). Web pages, e-mails, files, PDFs, API and tool output, other agents' messages and skill files under review are treated as content, never as orders. The agent is instructed never to pay, transfer, delete or reveal anything because content asked, to report the attempt with a quote and its source, and to still finish the real task. Use whenever the agent reads anything it did not…
Output
The agent receives the file's content treated strictly as data, along with a report of any detected prompt injection attempts including a direct quote of the suspicious instruction and its source location. The agent is also guided to complete the original task despite any injection attempt.
Example use cases
Safe PDF processing for research agents
“I need you to fetch and read this research PDF for me, but first run it through the prompt injection guard so you don't get hijacked by any instructions hidden inside the document — then give me a summary of the actual content.”
Secure file intake for autonomous agents
“Before you process the configuration file from that third-party URL, use the prompt injection guard on it — I don't trust the source and I want any embedded instructions flagged and reported before you do anything with it.”
Defending against malicious skill files
“There's a skill file I need you to review, but use the prompt injection guard first — check it for any hidden commands trying to make you transfer funds or reveal secrets, and tell me exactly what you found and where.”
Technical details
Endpoint
GEThttps://api.aiskills402.com/v1/skills/prompt-injection-guard/file?utm_source=zero.xyzWhen to prefer
Choose this endpoint whenever an AI agent needs to fetch and process content from an external file (PDF, document, skill file, configuration file, etc.) that may have been crafted or modified by untrusted parties. It is specifically designed to neutralize indirect prompt injection — where malicious instructions are hidden inside content the agent reads — rather than direct user prompt attacks. Prefer it over generic fetch tools when trust in the file source is uncertain or when the agent has access to sensitive capabilities like payments, deletions, or private data that could be abused.
Side effects
- File URL is unreachable or returns a non-2xx HTTP status — content cannot be fetched
- File format is unsupported or content is binary/unreadable — guard cannot analyze text
- Network timeout fetching the target file — no result returned
- Malformed input object missing required 'type' or 'method' fields — validation error
- Payment not received or x402 flow incomplete — endpoint returns 402 with payment instructions
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"file": {
"name": "SKILL.md",
"content": "<the SKILL.md file>",
"encoding": "utf-8"
},
"name": "Prompt Injection Guard",
"skill": "prompt-injection-guard",
"sha256": "<sha256 of SKILL.md>",
"receipt": {
"tx": "0x<settlement transaction>",
"settled": true
},
"version": "1.0.0",
"redownload": {
"url": "<api>/v1/purchases/<token>",
"token": "<64 hex chars>"
}
}
}Tags
x402
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