Design an embedding-keyed semantic cache for LLM responses that hits on similar prompts without serving wrong answers.
Cache hits on similar prompts cut cost and latency, but one false hit serves a stranger's answer to your question. Picking the threshold and handling user-specific data is the whole game.
Updated Aug 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
Cache hits on similar prompts cut cost and latency, but one false hit serves a stranger's answer to your question. Picking the threshold and handling user-specific data is the whole game.
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.
