I feel you have both missed the point of caveman reasoning.

LLMs are trained on human natural language, not a specialised internal-only monologue to make syntactic shortcuts. Their response should make grammatical sense to a human reader because they are mimicking human speech.

"foo bar" is ambiguous.

"pursue theory foo; no, this didn't lead anywhere, let's backtrack and pursue theory bar" is accurate, should be meaningful to LLM attention, but is too verbose.

The minimal caveman way to say this is "not foo. instead do bar".

This really should provide the LLM attention with everything it needs to grasp the intention, but with far fewer tokens used.

Instead of all this I could have just said:

"nothing ambiguous. clear but less words"