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.

Keep a pass yourself only when slicing it sharply would cost more than doing it — tiny fixups, plan reconciliation, integration conflicts.

Rules

• You own every result: read the full diff and run the verification yourself. "Codex says it's done" is never done.
• Visual results carry implement-spec's two extra proofs (production-route pixel diff + unprimed critique) with double force here: a sandboxed Codex never saw its change render, so a pass that misses the production render path entirely arrives looking fully "verified".
• A sandboxed Codex ships code it never saw run — browser-verify every visual slice yourself and budget fix rounds. Send a red gate back as a resumed follow-up with the failing evidence; fix it yourself only when that's smaller than re-prompting.
• Commit hygiene stays yours: review the change list of the merged tree before every commit, exactly as implement-spec demands of the integrating reviewer.