"Flat" matching MCP connectors:

Tokenbooks - crypto and fiat accounting and paymentsAOAuth

io.tokenbooks

Crypto and fiat on one double-entry ledger: sync wallets, reconcile, cost basis, audit-ready close.

No-account cross-chain crypto swaps (BTC, ETH, SOL, USDT, ZEC…) for AI agents. Flat 0.5% fee.

Flat 1-credit Base/ETH/XRPL RPC (eth_getLogs=1 credit), x402 wash filter, 0% checkout & tax CSV.

Find, price, rent and stop GPUs on AmpleRun. Paid in USDC or USDT on Base. Flat 5% fee.

61 x402 pay-per-call tools that chain: each answer names the next call. No API key, no account.

Settlement layer for AI agent commerce. 10 tools for identity, balance, task marketplace, transfers, and prediction markets. Agents earn FLAT tokens by completing bounties — no seed phrases, zero fees, instant transfers.

CPI-pegged stablecoin for AI agents. Zero fees, task board, self-register in 30s.