The MCP feature is like other OpenAI tools. It runs on the internal tool iterator. It employs internet-based resources. Think of it like the web search pattern.
You also might want to make up an “api key” for authentication so you aren’t serving up free resources to the world.
Paragraph 1 of documentation will key you in:
remote: The MCP tool in the Responses API allows developers to give the model access to tools hosted on Remote MCP servers.
internet: These are MCP servers maintained by developers and organizations across the internet…