NythosX

Agent Tools.

Pay-per-call tools for autonomous agents: live gas and fee prices across six chains, and web page to clean Markdown. Priced in USDC through x402 v2 on Base. No account, no API key. Failed calls are never charged.

Endpoints

MethodPathPriceWhat it does
GET/v1/gas?chain=base$0.002Current slow/standard/fast gas tiers and the USD cost of a transfer, USDC transfer or swap. Chains: base, ethereum, arbitrum, optimism, polygon, solana.
GET/v1/gas/compare?tx=usdc_transfer&tier=standard$0.005Where is it cheapest to send this transaction right now? Ranks all six chains by USD cost, returns the cheapest, and lists any chains that errored.
GET/v1/read?url=https://example.com$0.003Clean Markdown from any public web page: title, byline, site name, excerpt, word count, article body. Respects robots.txt, blocks private hosts, caps the page at 3 MB.
GET/v1/chainsfreeSupported chains and the gas-unit constants.
GET/v1/sample?endpoint=gas|compare|readfreeFixed-input sample response, cached hourly. Use it to shape a request before paying.

How payment works

Call a paid endpoint without payment and you get 402 Payment Required with a PAYMENT-REQUIRED header (base64 x402 v2). Sign the USDC payment, retry with PAYMENT-SIGNATURE. Settlement happens only after a successful 200 result, so failed calls are never charged.

curl

curl -i "https://tools.nythosx.com/v1/gas?chain=base" curl -i "https://tools.nythosx.com/v1/gas/compare?tx=usdc_transfer&tier=standard" curl -i "https://tools.nythosx.com/v1/read?url=https://example.com"

Minimal client (@x402/fetch + viem)

import { wrapFetchWithPayment, x402Client } from "@x402/fetch"; import { ExactEvmScheme } from "@x402/evm/exact/client"; import { privateKeyToAccount } from "viem/accounts"; const account = privateKeyToAccount(process.env.AGENT_KEY); const client = new x402Client().register("eip155:*", new ExactEvmScheme(account)); const pay = wrapFetchWithPayment(fetch, client); const res = await pay("https://tools.nythosx.com/v1/gas?chain=base"); const { data } = await res.json(); console.log(data.chain, data.costUsd.usdc_transfer.standard);

MCP

All three tools are available as Model Context Protocol tools at https://tools.nythosx.com/mcp (Streamable HTTP, stateless). Paid calls carry an x402 payment in _meta["x402/payment"]; x402-aware MCP clients handle this automatically.

Tools: get_gas_price ($0.002) · compare_gas_costs ($0.005) · read_url_as_markdown ($0.003) · list_chains (free)

Machine-readable

/openapi.json /api/catalog /.well-known/x402 /.well-known/agent-card.json /llms.txt

Every response is an envelope { schema_version, endpoint, generated_at, source_timestamp, data, disclaimer }. Paths are versioned; response shapes do not change within /v1. Informational data only — verify critical values before acting.