Short answer: An MCP gateway is the layer between an agent host and the MCP server. It adds what a raw server does not have: one upstream URL for every client, per-key and per-team request limits, budget caps clamped to the plan, and one audit row per tool call. A plain proxy forwards the same bytes and can describe none of it. Key takeaways The gateway owns policy, the server owns tools. A raw MCP server answers tools/list and tools/call ; it has no opinion about who may cal...