# Agent Tools: paid utilities with x402

Start with the free human and agent integration guide: https://agent-tools-x402.t6y11a.workers.dev/docs#use-from-agent
OpenAPI: https://agent-tools-x402.t6y11a.workers.dev/openapi.json
Download runnable Node client: https://agent-tools-x402.t6y11a.workers.dev/client.mjs

## Random integers: main supported paid use case
GET https://agent-tools-x402.t6y11a.workers.dev/api/random?n=5&min=1&max=100
Price: 0.002 USDC per call on eip155:8453. n=1..100, min/max safe integers; max-min <=1000000000000.
Returns integers, the public drand beacon round/randomness/signature, and derivation details.
Use for reproducible sampling, simulations and draws between trusting parties. Same parameters in the same latest30-second round repeat the result. NOT private randomness, secrets, keys or gambling. Source beacon is public/free; this price buys the packaged integer derivation and x402 interface, not exclusive data. No server BLS signature verification.

## Client flow
Unpaid requests return HTTP402 with PAYMENT-REQUIRED and a JSON body carrying resource, accepts and extensions. Use a current x402 v2 client that preserves resource and discovery extensions. The downloadable Node client uses @x402/fetch2.30.0 and @x402/evm2.30.0; default run only inspects the unpaid402. Its --pay mode signs a real payment using the caller's locally stored PAYER_KEY and USDC on Base. Review the file before authorizing it. Never send private keys to this service or in chat.
Handler errors do not trigger settlement. A settlement error or timeout can leave payment uncertain: preserve the client result/payment header and reconcile the original operation on-chain before a fresh authorization.

## Verify integers offline
UTF-8 encode the lowercase hex randomness TEXT, colon, decimal round, colon, zero-based i. SHA-256, interpret digest as big-endian integer, modulo(max-min+1), add min. Do not hex-decode randomness before hashing.
Real public fixture: round6596584, randomness99909959f2059f9ad497651a9be9ffe67cc0230e5f5d97139a005ed510446f37, n5/min1/max100 gives [44,36,62,6,11]. Source https://api.drand.sh/public/6596584 . Offline fixture, not a paid response or BLS verification. Live endpoint chooses latest round, not this fixed round.

## Other tools
POST https://agent-tools-x402.t6y11a.workers.dev/api/markdown:0.005 USDC, JSON {html,url?}. Caller supplies HTML; no caller-URL fetch.
POST https://agent-tools-x402.t6y11a.workers.dev/api/agent-scan:0.01 USDC, JSON {html?,robotsTxt?,llmsTxt?,headers?}. Heuristic checklist of unverified caller materials, not a ranking benchmark.
GET probes of these POST-only tools return405; call with POST for current payment requirements.
Free routes: /, /health, /docs, /openapi.json, /llms.txt, /client.mjs.
No accounts/API keys for this service. Payment requires the caller's wallet and supported client; the service's facilitator handles settlement directly to its receiving address.