External Runtimes Should Read AGENTS.md Directly

The cleanest APX design is not a translation layer. It is a handoff.

APC is the portable context layer. APX is the daily-use runtime and tooling layer. When APX launches an external runtime like Claude Code, Codex, OpenCode, or Aider, the job is simple: locate the project, start the runtime, and let that runtime read the project's own contract.

That keeps one source of truth in the repo and keeps APX thin.

Why this matters