Networks
MPP_STELLAR_NETWORK accepts stellar:testnet or stellar:pubnet and nothing
else; anything else is a configuration error reported once via PREFLIGHT.
Only testnet has a default RPC endpoint. Pubnet deliberately has none, so a
pubnet run must pass --rpc-url explicitly rather than silently reaching a
third-party node.
The x402 payment checks also pay on Base Sepolia (eip155:84532), through
--network (MCP: network), with the payer key in EVM_PRIVATE_KEY. Its
default RPC endpoint is Base's public https://sepolia.base.org, overridable
with --rpc-url. They pay on Solana devnet too
(solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1), with the payer key in SVM_PRIVATE_KEY
and the public https://api.devnet.solana.com as the default RPC endpoint. Any other
network gets the read-only checks only.