Q402 ships as a Model Context Protocol server. One install and Claude can quote stablecoin transfers across 7 EVM chains, settle them gaslessly, and confirm on-chain — all from a single prompt. The recipient gets the full amount. The sender pays $0 in gas. The agent never holds a key it shouldn't.
Sandbox-default — no API key, no signup, no funds at risk to try q402_quote.
Change the amount or token filter — the table re-ranks every chain by gas the same way the MCP server returns to Claude in real time.
No hidden admin endpoints, no key-rotation paths, nothing that could let a hallucination cost you money.
q402_quoteno authCompare gas + supported tokens across all 7 chains. Read-only, no key. Perfect first call before anything signs.
q402_balanceapi keyVerify the configured key and report its plan tier (live vs sandbox). Read-only.
q402_payapi key + signer + flagSend a gasless USDC or USDT payment. Sandbox by default — three env vars must align before a single wei moves.
Letting an LLM touch a payment rail demands more than “the model will be careful.”
Without three env vars (Q402_API_KEY live tier, Q402_PRIVATE_KEY, Q402_ENABLE_REAL_PAYMENTS=1), every q402_pay returns a fake hash. No funds, no quota.
Q402_MAX_AMOUNT_PER_CALL defaults to $5. Larger amounts are rejected before any signature happens.
Q402_ALLOWED_RECIPIENTS takes a comma-separated list. Unset = no restriction; set = nothing else gets through.
The tool description requires the model to obtain explicit user OK in chat before passing confirm: true. Combine with the cap and allowlist for defense in depth.
No signup. No API key. Sandbox-safe. Real payments later — your first $1 of gas is on us.
@quackai/q402-mcp · github.com/bitgett/q402-mcp · /docs → Claude MCP