Codex ⇄ Claude review debate

Automate the back-and-forth you'd otherwise courier by hand: codex (the reviewer) critiques the current change, a Claude subagent (the author) fixes what it agrees with and disputes what it doesn't, codex re-reviews, and so on — round after round, until they reach consensus. There is no round cap and no "deadlock" surrender: a debate that quits without agreement defeats the purpose, so the two sides keep arguing until one concedes. You stay out of the middle: each round lands as its own commit whose message carries the debate context (codex's findings + Claude's dispositions) so the PR history reads as the debate, and the summary is posted to the PR as a comment at the end.

Why this shape

The two sides are asymmetric, and that asymmetry is the whole design:

• codex is CLI-invokable headlessly (codex exec, authed via ChatGPT), so it runs from a shell command.
• Claude on a Max plan is not headless — claude -p doesn't work with Max auth. But the Workflow tool's agent() spawns Claude subagents through the harness, not claude -p, so it works. That subagent is the author side.

So the debate runs as a Workflow: agent() is Claude, a Bash-invoked codex exec is the reviewer, and the script couriers structured verdicts between them and decides when they agree. Both sides are forced to emit schema-constrained JSON, so consensus is detected in code, not by vibes.

This skill requires Claude Code's Workflow tool (it is the engine). Under codex/opencode runtimes the skill is inert.

Arguments

Parse [<pr-number>] [--base <branch>] [--no-commit] [--no-comment]:

• <pr-number> (optional): a PR to debate. If given, gh pr checkout <n> first and default the base to that PR's base branch. If omitted, debate the current branch's working-tree diff.
• --base <branch>: ref to diff against. Always a remote-tracking ref, never a stale local branch. Default: origin/<PR base> when a PR number is given, else the repo default branch as git symbolic-ref --short refs/remotes/origin/HEAD (e.g. origin/master) — used as-is, NOT stripped to local master (which can lag the remote). Fallback origin/master. Step 1 runs git fetch origin first so the ref is current.
• --no-commit: don't commit per round — leave all agreed changes uncommitted in the working tree for you to commit yourself. Default is to commit each round (see below).
• --no-comment: don't post the debate summary to the PR. By default, when a PR exists, the debate summary IS posted as a PR comment (see step 3). Pass this to suppress the outward-facing write and report in chat only.

Steps

1. Resolve context

• Determine repoPath (the worktree root, normally the cwd).
• git fetch origin so remote-tracking refs are current — the base is an origin/... ref, and a stale one would diff against the wrong tree.
• Resolve base per the rules above (a remote-tracking ref like origin/master).
• If a PR number was given, gh pr checkout <n> and confirm the branch.
• Confirm there is a non-empty diff: git diff --stat <base>. If empty, tell the user there's nothing to review and stop.
• Preflight codex: codex login status. If not logged in, stop and tell the user to run codex login (suggest the ! prefix to do it in-session).

2. Run the debate Workflow

Invoke the Workflow tool pointing at this skill's committed script, passing context through args:

Workflow({
  scriptPath: ".claude/skills/codex-debate/debate.workflow.js",
  args: {
    repoPath: "<worktree root>",        // also the per-worktree scratch dir root
    base: "<base branch>",
    commit: <false only if --no-commit>,
    skillDir: ".claude/skills/codex-debate"
  }
})

The workflow runs in the background and notifies you when it completes. It alternates codex:roundN and claude:roundN agents under a Debate phase — the user can watch live via /workflows. Each Claude round edits the working tree, then (unless --no-commit) a commit:roundN agent commits exactly that round's changed files with a message embedding the round's codex findings and Claude's dispositions — never pushing or merging.

Ephemeral scratch (verdicts, rebuttals) lives under the gitignored, per-worktree <repoPath>/.codex-debate/, so parallel debates in different worktrees never collide and the scratch never shows up in the diff codex reviews. It returns:

{ status: "consensus" | "reviewer-error",
  rounds, base, finalVerdict, filesChanged, transcript }

(each transcript[] round also carries a commit SHA when that round committed.)

• consensus — codex approved with no blocking/major findings open. This is the only way the debate ends normally: it keeps running rounds until codex and Claude agree, with no round cap and no deadlock exit. (The harness's own per-workflow agent backstop is the sole hard ceiling; if you ever need to stop a debate by hand, interrupt it via /workflows or TaskStop.)
• reviewer-error — the one abnormal terminus: codex itself failed to produce a verdict (broken/unavailable CLI), so the workflow synthesized an error verdict and aborted rather than spin forever on a dead reviewer. This is infrastructure failure, not a debate outcome — finalVerdict.summary carries the failure detail. Do not treat it as consensus (see step 3).

3. Present the result

First branch on status. If status === "reviewer-error", the debate did not reach consensus — codex never produced a real verdict. Report it as a failure, not a success: surface finalVerdict.summary (and the workflow log) so the user sees codex was broken/unavailable, and tell them to fix codex (e.g. codex login, check the CLI) and re-run. Do not post a consensus badge or a ## Codex ⇄ Claude debate PR comment for this path — there is no agreement to report. Skip the rest of this section.

Otherwise (status === "consensus") report in chat (do not push or merge — the per-round commits sit on the local branch for the human to review):

• The outcome — consensus — and how many rounds it took to get there.
• The reviewer's reasoning effort: codex runs at xhigh (scoped to the debate via -c model_reasoning_effort=xhigh in codex-review.sh, regardless of the user's global codex default). State this so the depth of the review is on the record.
• git log --oneline <base>..HEAD (the per-round debate commits) and git diff --stat <base> so the user sees what the debate changed.
• A compact per-round table from transcript — each round's codex verdict (approved? open blocking/major count), Claude's dispositions, and the round's commit SHA — so the convergence reads round by round.
• The agreed changes are committed per round on the local branch (or, under --no-commit, uncommitted in the working tree). The user reviews, then pushes / merges (or runs /do --from post-implement) when satisfied.
• Post the debate summary to the PR (default). When a PR exists and --no-comment was NOT passed, post a ## Codex ⇄ Claude debate comment via gh pr comment. Include: the consensus outcome badge and the round count; a note that codex reviewed at xhigh reasoning effort; and a per-round table (codex approved? open blocking/major findings; Claude's dispositions; the round's commit SHA) showing how the two sides converged. Use a single-quoted heredoc so backticks/$ survive. This is an outward-facing write — it's on by default because the whole point is to leave the review trail on the PR; --no-comment suppresses it.

Safety & notes

• codex runs read-only — enforced, not just asked. codex is invoked with --sandbox read-only, so the kernel sandbox blocks file writes and other state-mutating syscalls; the prompt's "don't write" instruction is belt-and- suspenders, not the only guard. This matters because codex reviews arbitrary diffs and could be prompt-injected by file contents. The only writes to the tree come from the Claude author rounds. (codex auto-falls-back to its bundled bubblewrap when the system one is absent, so read-only works in containers.)
• Commits, but never pushes or merges. Each round is committed locally (unless --no-commit) so the PR history reads as the debate, but the skill never pushes or merges. Consensus means "both AIs agree on the committed code," not "ship it" — the human reviews the commits and pushes/merges.
• Parallel-safe. Ephemeral scratch (verdicts, rebuttals) lives under the gitignored, per-worktree <repoPath>/.codex-debate/, so debates on many worktrees run at once without clobbering each other — no shared /tmp paths.
• Posts to the PR by default. When a PR exists, the debate summary is posted as a PR comment (outward-facing write) unless --no-comment is passed — the point is to leave the review trail on the PR.
• Runs to consensus — no cap, no deadlock exit. The loop ends only when codex and Claude agree; it does not bail out at a round cap or declare a "deadlock," because a debate that quits without agreement is pointless. The two sides keep arguing until one concedes. The harness's own per-workflow agent backstop is the sole hard ceiling; interrupt via /workflows or TaskStop if you ever need to stop one by hand.

Files

• debate.workflow.js — the Workflow script (the loop + consensus logic).
• scripts/codex-review.sh — the canonical, deterministic codex exec invocation.
• scripts/codex-verdict.schema.json — the JSON Schema codex's verdict is constrained to.

These are generated from .apm/skills/codex-debate/; edit the source there and run just ai apm to regenerate.

ARGUMENTS: $ARGUMENTS