Last reviewed
Correct answer: D. The model decides which tools run; the host application decides which resources are pulled in.
Explanation
The principle — Each primitive has a fixed controller, and that is what makes the three of them different from one another.
Why the key is correct — Tools are model-controlled, meaning AI models can discover and invoke them automatically. Resources are application-driven, giving them flexibility in how they retrieve, process, and present available context.
Why the others are wrong — The application carries the call but does not choose it. The model does not choose its resources. And control is a property of the primitive rather than of the last person to act.
Remember this — Model reaches for tools; the application reaches for resources.
Sources — MCP first-party documentation.
Sources
“Tools are model-controlled, meaning AI models can discover and invoke them automatically.”
“Resources are application-driven, giving them flexibility in how they retrieve, process, and present available context.”
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