tl;dr: Sphinx is a Git pre-push hook that quizzes developers on AI-generated code before it ships, asking questions about what the diff actually does in failure scenarios. It works with Codex, Claude Code, Cursor, OpenCode, Pi, or plain Git, and runs through your existing coding agent, OpenRouter, or any OpenAI-compatible endpoint. A `sphinx yolo` escape hatch lets pushes through when needed, with skips logged.