Short Answer

Design the retrieval architecture when 95% of queries carry five or more metadata predicates of wildly varying selectivity.

PremiumDiagnose why a pgvector…

Design an auto tuner that adjusts ef_search to hold recall@10 at 0.95 as data and traffic drift.

Design a CI gate that blocks deploys when vector index recall regresses.

PremiumDiagnose a recall@10 collapse…

Estimate the infrastructure gap between in RAM HNSW and NVMe DiskANN for one billion 1024-dim vectors.

Walk through orchestrating a 500M-vector re-embedding backfill: rate limits, checkpoints, verification, and cutover readiness.

Design search over 100M vectors for 6,000 tenants where one tenant owns 40% of the data.

Walk through what quadrupling vocab to 128k does to params, compute, and sequences

Rescue a streaming deployment that collapses once early tokens leave the cache

Architect a layer pattern mixing sliding window and global attention for huge contexts

Diagnose attention logit explosion in a large run and defend QK-norm as the fix

Diagnose why a 48-layer model diverges right after a pre-norm to post-norm refactor

PremiumDebug a 64-layer stack…

Evaluate depth up scaling: duplicating middle layers to grow a model mid stream

Design an ablation study that fairly tests a new transformer block modification

Defend dropping the value network: when does critic free RL break down?

PremiumLive thumbs up training…

Diagnose a run where reward climbs steadily but human evals stay flat

PremiumRefusals jumped from 2%…

Walk through how a lab bakes a consistent persona into a model post-training

Design an online preference learning loop fed by live production traffic

PremiumKL blew past target…

Using an LLM judge as the training reward: list the failure modes you'd watch

PremiumSketch the reward overoptimization…