In MCP architecture, executable capabilities are exposed by an MCP server . The server advertises available tools through the protocol, including each tool's name, description, and input schema. An MCP client discovers those capabilities using tools/list and invokes a selected tool through tools/call . The uploaded course material therefore correctly identifies the separate MCP server as the location associated with production MCP tool implementations.

The official MCP architecture defines an MCP server as the program that provides context and capabilities to MCP clients. It also defines tools as executable functions exposed by servers for actions such as API calls, database queries, or file operations. During execution, the AI application routes the model-generated tool call through the corresponding MCP client to the appropriate MCP server.

Tools are not encoded into an LLM's trained weights. Locally defined function tools can indeed be declared in agent code, but that is distinct from an MCP-served tool. Likewise, the MCP client handles communication and protocol coordination; it is not conceptually the server-side implementation host.

Therefore, A is architecturally correct.

Study Guide reference/topic: Model Context Protocol (MCP) Fundamentals — MCP Servers, tool hosting, tools/list, tools/call, and client-server separation.

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