Your MCP Server Authenticates the User, Not the Tool Call
Microsoft states it in an Important callout: MCP server authorization defines access to the server and does not reach individual tools. The protocol makes authorization optional, any connected caller can list every tool and read every description, and the token you issue must not be forwarded to the systems behind. What holds the line is the tool calling the same service method your screens call, so that one rule change covers both and neither drifts.
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