# x402check skills

Task-specific instructions agents can load on demand. Machine index: [`/.well-known/skills.json`](https://x402check.dev/.well-known/skills.json) and [`/.well-known/agent-skills/index.json`](https://x402check.dev/.well-known/agent-skills/index.json).

## x402-preflight

**When:** about to pay / settle / sign `PAYMENT-SIGNATURE` for any x402 tool; asking “is this API a scam?” / “is this endpoint safe?”; verifying payTo; checking uptime or price/wallet drift.

**Do:** call `GET https://x402check.dev/preflight?url=SELLER_URL` (or MCP `preflight_check`) **before** paying the seller. Deny on `avoid`. Unit **$0.01** USDC on Base after one free check per wallet.

Full skill: [https://x402check.dev/.well-known/agent-skills/x402-preflight/SKILL.md](https://x402check.dev/.well-known/agent-skills/x402-preflight/SKILL.md)

Always-on project instructions: [https://x402check.dev/AGENTS.md](https://x402check.dev/AGENTS.md)