What problem does it solve? LLM application code fails in ways that pass code review: prompt injection through tool results, retries that re-execute refunds, context budgets measured with character heuristics, and evals whose average score hides catastrophic regressions. This Skill encodes 25 incident-derived rules and gated workflows to catch those defects before they ship. ## Core Features & Use Cases - Review workflow: Audits model-calling code against a trust-boundary map, tool reversibility table, budget checks, and output-contract rules, with every finding tied to the observable failure it causes. - Build workflows: Step-by-step checklists for writing tool-using agent loops (turn caps, idempotency keys, per-phase tool sets) and RAG pipelines (chunking units, relevance floors, citation ids, embedding symmetry). - Evaluation workflow: Designs per-case pass/fail gates with must-never-fail sets, held-out leakage control, judge bias mitigations, and trajectory assertions instead of average scores. - Use Case: Given a support-agent loop that issued wrong refunds and burned $190 on one ticket, the review workflow identifies the tool-result-as-user-turn injection path, the missing turn cap, and the retry wrapper multiplying paid requests. ## Quick Start Ask the agent to review your agent loop, RAG pipeline, or eval harness file using the ai-engineering skill and list each defect with the failure it causes.