Given a new LLM use case, how do you decide between prompting, RAG, fine-tuning, and tools/agents?
The senior signal is fitting the method to what is genuinely missing rather than reaching for your favorite. Knowledge, behavior, or actions each steer you to a different tool. Here is the decision framework that scores highest.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
The senior signal is fitting the method to what is genuinely missing rather than reaching for your favorite. Knowledge, behavior, or actions each steer you to a different tool. Here is the decision framework that scores highest.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
