Every other portage-ucp gem lets a Ruby program expose a commerce backend to agents (server side). This gem is the other direction: connect to somebody else's /.well-known/ucp manifest, or drive your own Adapter directly, and place an order as the client. Three transports behind one interface (loopback over an in-process Adapter, stdio, Streamable HTTP) — callers never know which they got. Depends only on portage-ucp + the mcp gem's client half; no adapter gem is a dependency.