Implement Spec With Codex Skill for Codex

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.