privacy

Zero retention, private endpoints, redaction pipelines, or open weights in their VPC, the four-rung ladder for PII-sensitive deployments, and the discovery questions that pick the right rung.

Memory is a retrieval problem plus a write-policy problem plus a privacy problem. Most candidates only design the first. Covers memory taxonomies, the curation pipeline, and the leak vectors that fail the question.

The hard part is not the retrieval pipeline, it is the boundary. Embeddings and the index live inside the VPC; the only question is whether the generation model is an in-VPC open model or an external API with a zero-retention DPA, and what crosses that line.

A deceptively simple screener: each detection method maps to a PII class, and the 'why not regex for names' sub-question has a precise answer about structure vs context that interviewers use as the pass bar.

The four-point redaction design is becoming the standard FDE privacy round. Most candidates fortify the chat box and lose on the other three doors, here's the full design, including the de-redaction map that makes it usable.

Every EU enterprise deal hits this question, and the FDE in the room is expected to carry it without legal on the call. The processor/controller split, the transfer mechanics, and the one GDPR right that's hard for LLMs.

Sensitive meeting audio in, speaker-attributed summary out, and a hard guarantee that the raw transcript never lands on disk. The strong answer keeps everything on-prem, processes transcripts in memory only, and proves non-retention with architecture and audit, not a policy promise.

Fine-tune a LoRA adapter on the user's typing on the phone's neural engine, add noise locally with DP-SGD, and aggregate only adapter deltas, so no individual's vocabulary is recoverable from the global update.