Anything that can do RAG is, by definition, a system that wraps an LLM with additional code that performs the retrieval.
It's the difference between ChatGPT (software that wraps a model and can extra features such as tool usage, Code Interpreter, RAG lookup via Bing etc) and GPT-4 Turbo (a model).
In order to use tools they need to be run as part of a system that grants them access to tools, eg via the reAct pattern. https://til.simonwillison.net/llms/python-react-pattern
Obviously I’m talking about next gen models, like gpt5/6.
As you train a model it should build it's knowledge database at the same time. I guess that's how it work?
When an LLM get trained on next word guessing, can it search the web to improve his results?
You wouldn’t say a steering wheel is built into an engine. People just build cars with engines.