How On Codex, read the platform mapping, including its per-skill notes, before following this skill. On GitHub Copilot, read the platform mapping, including its per-skill notes, before following this skill. On Muse, read the platform mapping, including its per-skill notes, before following this skill. Explore the codebase to answer "how does X work?" questions. Produce architectural explanations at the level of a senior engineer onboarding onto a subsystem, enough to build a working mental model, not so much that it reads like annotated source code. Every spawn is a subagent with and . Explor…