Last-mile 1Z0-1127-25 review: RAG pipeline, chunking and embeddings pickers, evaluation signals, prompt injection defenses, deployment patterns, and cost/latency controls.
Use this for last‑mile review. Pair it with the Syllabus.
flowchart LR
DOC["Docs"] --> CH["Chunk + clean"]
CH --> EMB["Embeddings"]
EMB --> IDX["Vector index"]
Q["Query"] --> QEMB["Query embedding"]
QEMB --> RET["Retrieve top-k"]
RET --> PROMPT["Prompt with context"]
PROMPT --> LLM["LLM"]
LLM --> OUT["Answer + citations"]
Rule: “Better prompts” rarely fix a broken retrieval layer.
| Decision | Too small | Too big |
|---|---|---|
| Chunk size | low context | low precision |
| Overlap | wasted cost | continuity breaks |
| Metadata | missing filters | wrong tenant/version |
| Layer | What to measure |
|---|---|
| Retrieval | hit rate/top‑k relevance, filter correctness |
| Generation | groundedness, correctness, citation quality |
| Safety | leakage, injection resilience, policy violations |