MCP gateway
A single MCP endpoint that fronts several underlying platforms, so one connection reaches all of them under one authentication and one set of conventions.
What makes it wrong.
The mechanism, not the warning.
A gateway is also a single point of scope. What it can reach is what every tool can reach, so the account allowlist matters more here than on a single-platform server: it is the only boundary between one client's data and another's.
In detail.
A gateway exists because the questions people ask cross platforms and the servers do not. Answering whether search spend moved organic rankings means holding Google Ads and Search Console in the same reasoning context, with periods that line up and metric names that mean the same thing on both sides.
The alternative is several servers wired into the same client, which works, and costs a reconciliation the model performs on every question: different authentication, different naming, different date semantics, different write behaviour.