personalization

Cross-session memory is what makes an assistant feel personal, and it is mostly a retrieval and state-management problem, not a bigger context window. The signal is the tiered architecture plus what to store, forget, and protect.

Summarize, draft, triage, all over the most sensitive PII a person owns. The signal is grounding in the actual thread, matching the user's voice, and a hard human-in-the-loop rule on anything that gets sent.

E-commerce search is where retrieval, ranking, and business goals collide, and it carries a hard exact-match requirement (brand, size, SKU). The signal is query understanding plus hybrid retrieval plus business-aware ranking. Here is the design.

Notification systems fail by spamming users into muting them, and a mute is a permanently lost channel. The signal is treating it as a per-user send/hold/batch/suppress decision optimized for long-term trust, not for clicks or volume.

Personalizing an LLM is a retrieval and memory problem, not a per-user fine-tune. Learn how to assemble user context at request time, manage long-term memory without bloating the prompt, and respect privacy and the right to be forgotten.