Agent Skills: codex-plan-reviewer

Cross-model adversarial review loop for markdown plans. Use this skill whenever the user asks to review, validate, or stress-test a markdown plan file using Codex (OpenAI). Triggers on phrases like "review this plan with codex", "let codex check the plan", "adversarial review", "cross-model review", "codex audit", "validate plan", or when the user has a markdown plan and wants a second opinion from a different AI model. Also trigger when the user says "plan review loop", "codex review loop", or references having Codex critique a plan before execution.