An agent with no shell can open and pay for an account over MCP

Two new tools, runtime_wallet_open and runtime_wallet_claim (also at /mcp?signup=wallet), open an account paid in USDC: the first answers with an address per network, the exact amount and a claim code; the second connects once the payment lands. There is no free trial on this path. The Go, Ruby and Java SDKs gain the wallet calls, and runtime_connect picks up a key saved after the MCP server started. See pay with stablecoins.