Codex reads AGENTS.md by default, not CLAUDE.md. Move project guidance to AGENTS.md (trim/nest long validation notes under docs/AGENTS.md), leave CLAUDE.md as a thin @AGENTS.md wrapper for Claude Code, and document the Codex project_doc_max_bytes raise needed for the ~35KiB root file. Co-authored-by: Colby McHenry <colbymchenry@users.noreply.github.com>