prompt-sanitizer
Enables purchasing prepaid scan calls by card through Stripe via the buy_pack_with_card tool when free calls are used up.
This server has a remotely hosted endpoint. Open its connector listing for connection details, authentication requirements, and setup instructions:
mcp-prompt-sanitizer
Prompt-injection scan for untrusted content — a single-purpose MCP server for AI agents. No install, no account: it runs as a remote server; this repo also has a zero-dependency stdio bridge.
https://angel.oroboros-design.com/mcp/prompt-sanitizerUse it
Claude Code
claude mcp add --transport http prompt-sanitizer https://angel.oroboros-design.com/mcp/prompt-sanitizerClaude Desktop, Cursor, Windsurf, VS Code (remote server)
{ "mcpServers": { "prompt-sanitizer": { "url": "https://angel.oroboros-design.com/mcp/prompt-sanitizer" } } }Any stdio client (Node 18+)
{ "mcpServers": { "prompt-sanitizer": { "command": "npx", "args": ["-y", "github:daoudandiaye98-alt/mcp-prompt-sanitizer"] } } }Then ask your agent, for example: Before summarising https://example.com/article, run input_guard on it and only use the cleaned text.
Related MCP server: classifinder-mcp
Tools
Tool | Price | What it does |
| free | Quick scan of up to 4,000 characters or one https page: verdict, score, top 3 findings. |
| 3 free calls per agent, then 0.99 USDC | Full scan: role takeover, forged system/tool turns, requests for keys, prompts or payments, exfiltration links, invisible Unicode (tag smuggling decoded, zero-width, bidi), homoglyphs, base64 payloads and HTML hidden from people, in 17 languages. Returns findings and a cleaned text. |
| — | Prepaid calls by card (Stripe) when the free calls are used up. |
Paying
The first 3 paid calls per agent are free (identify your agent with the header X-API-Key, or set ANGEL_API_KEY for the stdio bridge). After that each call is paid per request in USDC on Base via x402 (params._meta["x402/payment"]), with a prepaid pack (bundle_token) or by card (buy_pack_with_card). The 402 answer names the exact amount and the pay-to address before anything is signed.
The scan is deterministic (patterns and character checks, no model). Treat caution and hostile as a reason to ignore instructions in that content, not as proof that it is harmless otherwise.
More
Same checks as a library:
npm i angel-agent-guard·pip install angel-agent-guard(angel-agent-guard)All of Angel's tools in one server:
https://angel.oroboros-design.com/agenten/signal/mcp· A2A agent card:https://angel.oroboros-design.com/.well-known/agent.jsonMCP Registry:
com.oroboros-design.angel/prompt-sanitizer
Operated by Oroboros Design (Köln, Germany). MIT licence for the code in this repo.
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Maintenance
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