Implement Spec with Codex

Run implement-spec exactly — same loop, same gates, same maintenance checkpoints — but Codex writes the code. Invoking this skill IS the explicit ask that authorizes codex exec delegation under the codex skill.

Role split

• Codex implements — whenever possible. Default every implementation pass to a codex exec, sliced sharp and prompted per the codex skill (prompt blocks, sandbox choice, exec liveness). Run independent slices as concurrent execs in separate worktrees, exactly where implement-spec would fan out subagents.
• You orchestrate and review. The spec loop stays yours: pick the next slice, reconcile plan with code, author each prompt end-to-end, integrate diffs, run the gates, review the merged tree, commit, update the handoff, run maintenance checkpoints. None of that delegates.