Gas optimizer

Find the cheapest gas right now: Base gas, Ethereum gas, Base fee estimate, and ETH price for USD conversion.

When to use this pack

Timing a transaction - compare gas across chains and decide whether to act now or wait.

Tools in this pack

All 3 run inside the single $0.007 call above. Each is also callable on its own if you only need one part.

• Gas snapshot (slow / standard / fast) POST /api/gas-snapshot Live gas price snapshot for a chain - slow / standard / fast tiers in gwei, plus the latest base fee. Sampled from eth_feeHistory (last 4 blocks, 25th/50th/90th percentile priority fees). Use to estimate before broadcasting a transaction from another tool.
• Gas price GET /api/gas-estimate Current gas price on Base, Polygon, Arbitrum, Optimism, Ethereum, Monad, Celo, Avalanche, Sei, or Robinhood Chain - for an agent budgeting a transaction: returns network, gasPriceGwei and gasPriceWei (decimal strings) from the chain's own eth_gasPrice, the node's suggested all-in price per gas unit. Multiply by the gas a transaction uses (21000 for a plain transfer) for its fee. Read-only. ?network=base
• Crypto price GET /api/crypto-price Live crypto prices for one or many coins in any vs_currency (usd, eur, btc, eth, etc). Returns last price, 24h change %, 24h volume, and market cap per coin. The simplest crypto price read - for ranked market-cap tables use crypto-market, for candles use crypto-history. Accepts ticker symbols (BTC, ETH, SOL) for the top ~50 by market cap, or canonical CoinGecko ids (e.g. "render-token") for any of the ~15k tracked coins. Batched: up to 25 coins per call. Backed by CoinGecko's API (this server's Demo key when configured, else the shared keyless rate).

Bought one at a time, these 3 tools cost $0.007 together; the pack is that sum less a 10% bundle discount, rounded up to the $0.001 settlement floor, which is $0.007.

Workflow

1. Get Base gas tiers (slow/standard/fast).
2. Get Ethereum gas tiers for comparison.
3. Get a Base fee estimate for a standard transfer.
4. Get ETH price to express costs in USD.

What one call returns

A JSON object with pack, args, steps, summary; steps holds one entry per tool (gas-snapshot, gas-estimate, crypto-price), each with its own result or error. Full example on the API page.

Call it directly

Any x402 client pays the 402 and gets the whole workflow back in one response. With the agent402-client SDK (npm i agent402-client, an ES module):

import { Agent402 } from "agent402-client";
// payFetch: an x402-wrapped fetch your wallet signs (@x402/fetch).
// Tools on the free tier need no options: new Agent402() pays them by proof-of-work.
// an existing prepaid credits key also works: new Agent402({ creditsKey })
const client = new Agent402({ fetch: payFetch });
const result = await client.call("skill-gas-optimizer", {});

Run it in Claude

claude mcp add agent402 -s user -- npx -y agent402-mcp@latest

Then paste this prompt into Claude:

Find the cheapest gas right now using Agent402's gas-optimizer skill pack. Get (1) Base gas tiers, (2) Ethereum gas tiers, (3) Base fee estimate, (4) ETH price. Tell me the cost in USD and whether to act now or wait.

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