Cross-model review skills for Claude Code, OpenAI Codex CLI, and Antigravity CLI: the agent you work with orchestrates, and a second model reviews its plans, code and reasoning under a compiled 3-layer Principal Reviewer system prompt. The reviewer is the Codex CLI by default; Claude Code (claude) and Antigravity (agy) can review too. The runner drives each reviewer CLI through its own adapter (scripts/lib/reviewers/).
Six skills (Claude Code & Antigravity: /name, Codex: $name):
loop-plan — write a phased, code-grounded implementation plan for large, multi-feature workloop-implement — execute an approved loop plan phase by phase with TDD, checkpoint reviews, and commitsreview-plan — debate implementation plans before codingreview-impl — review uncommitted changes, unpushed commits, or a branch before commit/push/mergereview-think — peer reasoning/debate on technical topicsreview-pr — review someone else's PR as a peer (correctness, description, merge readiness); your own PR goes through review-impl
This project was called codex-review (lploc94/codex_skill, skills codex-plan-review, codex-impl-review, codex-think-about, codex-commit-review, codex-pr-review). Installing removes that pack's skills, runtime and MCP server registration. Finish any review that is still running before you update: sessions started under the old names cannot be resumed.
Benchmark: which reviewer to pick
We gave the same 168 pull requests (144 with planted bugs, clean ones and decoys, plus 24 real bugs from open source) to Codex (gpt-6-astra), Claude Code (claude-opus-5-5) and Antigravity (gemini-4-argon), three runs each at effort high, all through review-impl, and graded every finding blind with a three-judge panel and an audit. The method was pre-registered. Full write-up: cross-review.tlelabs.com/benchmark; code, public tasks and report: lploc94/cross-review-bench.
- Codex and Claude Code find the most bugs: about 90% of the planted bug weight, with no significant gap between them.
- Antigravity raises the fewest false alarms: 87% of its findings were real, and it asked for changes on 5% of correct pull requests, against 21% for Claude Code and 48% for Codex. That gives it the best F1, but it misses more of the hard bugs.
- Claude Code is the best all-rounder: Codex-level detection, less than half of Codex's false alarms, and the fastest median run (141 s).
- On real bugs Codex leads (F1 0.58, Claude Code 0.53, Antigravity 0.45).
- A second model did not fix more bugs: when Claude Code or Codex fixed buggy pull requests, adding a reviewer did not raise the share fixed over the agent reviewing its own work.
Planted corpus (144 pull requests); brackets are 95% bootstrap intervals over tasks:
Detection against noise (the dotted curves are equal F1):
False alarms: the share of correct pull requests (clean or decoy) on which the reviewer asked for changes over something that was not a bug:
Recall by difficulty, from L1 (visible in the diff) to L4 (needs running the code):
Real defects nobody planted, confirmed by the audit (60 in all):
Real bugs from public repositories, fixed after every model's training cutoff (21 scored):
The second round: does the reviewer accept a correct fix, catch a wrong one, and hold against a false rebuttal?
Fix loops: share of bugs fixed when Claude Code or Codex fixes 40 buggy pull requests alone or with each reviewer:
Median time per review run:
Pick Codex or Claude Code when a missed bug costs more than a false alarm, Antigravity when noise is the problem, and Claude Code for a balance of both. See Choosing the reviewer.
Requirements
- Node.js >= 22 and npm
- Claude Code CLI and/or Codex CLI
- At least one reviewer CLI in PATH, signed in:
- macOS, Linux or Windows. On Windows the reviewer CLIs may be
.exe files or npm installs (.cmd), and the cross-review command works in PowerShell 7, cmd and Git Bash
Install
npx @tlelabs/cross-review
From GitHub instead: npx github:lploc94/cross-review.
What it does
- Installs the skills for Claude Code into
~/.claude/skills/, for Codex into ~/.agents/skills/, and for Antigravity (agy) as the cross-review plugin into ~/.gemini/config/plugins/cross-review/ (including 6 skills, 4 reviewer agents cross-reviewer-review-{impl,plan,pr,think}, and enabling the plugin in ~/.gemini/config/config.json)
- Installs the shared runtime (runner, MCP server,
build-prompts.js, compiled 3-layer reviewer prompts, and dependencies from the lock file) into ~/.claude/skills/cross-review/
- Renders each SKILL.md with the shared review protocol and the absolute runner path
- Registers the
cross-review MCP server with Claude Code (user scope), Codex, and Antigravity (~/.gemini/config/mcp_config.json)
- Swaps directories atomically with rollback on failure; removes the old
codex-review pack and this pack's copies in ~/.codex/skills
- Writes the
cross-review command, a small script that runs the installed runner: ~/.local/bin/cross-review on macOS and Linux; on Windows cross-review.cmd, cross-review.ps1 and cross-review (for Git Bash) in npm's global folder (npm prefix -g, usually %APPDATA%\npm, which is on your PATH). A file of that name the installer did not write is left alone. When the folder is not on your PATH, the installer says so
Windows PowerShell 5.1 blocks .ps1 files by default: type cross-review.cmd there, or allow local scripts with Set-ExecutionPolicy -Scope CurrentUser RemoteSigned. PowerShell 7 runs them as they are.
Verify
node ~/.claude/skills/cross-review/scripts/review-runner.js version # 15
claude mcp get cross-review
codex mcp get cross-review
Reinstall / Update
npx @tlelabs/cross-review@latest
Re-running is safe: the MCP registration is replaced, not duplicated.
Automatic reviews (optional)
npx @tlelabs/cross-review --auto
Adds a block to ~/.claude/CLAUDE.md and ~/.gemini/GEMINI.md that has Claude Code and Antigravity use the review-plan skill after finishing any plan and the review-impl skill after finishing any implementation, without asking first. This applies to every plan and implementation, not only loop-plan and loop-implement. It skips trivial changes, reviews a loop skill already ran, and reviews you asked it to skip. The other skills are never run automatically. Idempotent — safe to re-run. Every install, with or without --auto, refreshes a block that is already there, including one written by the old codex-review pack.
Usage
loop-plan writes a loop-plan/v1 plan with review checkpoints into <repo>/.cross-review/plans/; it is approved by review-plan or by you.loop-implement executes the approved plan, ticks each acceptance criterion it meets (- [x]), and runs review-impl at the plan's checkpoints.- The review skills use the MCP tools
review_begin, review_wait, review_reply, review_end. Without MCP, or in a mode that refuses the tools, they run the same verbs through the CLI: node ~/.claude/skills/cross-review/scripts/review-runner.js begin|wait|reply|end.
- Review sessions and plans live in
<repo>/.cross-review/, which ignores itself in git. Plans stay out of git too unless you turn on Plans in git (below).
The reviewer runs with full access so it can run tests and network commands (curl, npm view, git fetch) to check its findings; its prompts forbid changing project files.
Decision points: every regex, parser, guard, allow/deny list, default, fallback, timeout, retry or numeric bound a change adds needs a grounded source (real samples, a cited specification, or an exhaustive test) and a check of what it misses and what legitimate input it blocks. The reviewer blocks approval on an ungrounded one and lists each in a ### Decision Ledger table; a test that still passes with the fix disabled is a high finding.
Choosing the reviewer (optional)
Codex reviews unless you choose another reviewer:
- for one review, name it when you ask ("review this with Claude Code"); the skill passes
reviewer (codex, claude or agy) to review_begin, and the session keeps it for every round;
- as a default, set
"reviewer" in ~/.cross-review/config.json or <workspace>/.cross-review/config.json, or pick it in the dashboard's Settings.
Each reviewer keeps its own model and effort under reviewers.<name>, so switching reviewers never hands one CLI another's model:
{
"reviewer": "claude",
"reviewers": {
"codex": { "model": "<codex model>", "effort": "high" },
"claude": { "model": "opus", "effort": "max", "skills": { "review-pr": { "effort": "high" } } },
"agy": { "model": "<agy model family>", "effort": "low" }
}
}
- Codex: the models
codex debug models lists; effort as Codex names it.
- Claude Code: the aliases (
opus, sonnet, …) or a full model name; effort low, medium, high, xhigh or max.
- Antigravity:
agy models lists one model per effort (<family>-low, <family>-high, …). Pick the family and an effort, and the runner passes both to agy (--model <family> --effort <level>); a model listed without levels takes no effort. A level the family lacks fails before the review starts.
model, effort and skills at the top of a file are the older form of reviewers.codex and are still read that way; the dashboard saves them under reviewers.codex.
A reviewer never starts a review of its own: the runner marks the reviewer's environment (CROSS_REVIEW_REVIEWER), and a begin inside it fails with NESTED_REVIEW. This matters most when Claude Code reviews, since the cross-review skills are installed for it too.
Choose a model (optional)
Name a model or effort when you ask for a review (or in a plan's review checkpoint). The skill passes it to review_begin; the runner stores it and reuses it for every later round. Without one, the runner applies the dashboard settings (below) for the chosen reviewer, else the reviewer CLI's default model and effort high.
Dashboard
cross-review dashboard # the command the installer writes (~/.local/bin, or npm's folder on Windows)
npx @tlelabs/cross-review dashboard # without installing
| Plans: a plan's progress | Settings |
|---|
| |
Starts a local web page and opens it in your browser. It lists the review sessions and plans in the folder you start it from and up to 3 levels below. Options: --root <dir> scans another folder, --port <n> picks the port (default: a random free one), --no-open only prints the link, --idle-exit <s> stops the server after that many seconds with no page open.
- Sessions: reviews in progress (reviewer working, waiting for the agent, stopped) update live; History lists the finished ones with filters. A review left waiting for the agent, or stopped, for over an hour moves to History (
no reply or stopped) and comes back when the agent resumes it. A session's page shows the conversation round by round, the issue ledger, and what the reviewer is doing right now. The dashboard only reads sessions; it never starts, stops or answers one.
- Plans: every plan in
.cross-review/plans/ with its state (draft, in review, ready, phase N of M, done) and progress, live. A plan's page has two tabs: Progress (phases, their criteria, checkpoints, commits, the progress log) and Plan (the whole file with its contents). Another .md file in that folder shows as a plain document. Plans elsewhere in the repository are not shown.
- Settings: the reviewer, and each reviewer's model and effort, that a review uses when you do not name them, saved as you change them, globally (
~/.cross-review/config.json) or for one workspace (<workspace>/.cross-review/config.json, ignored by git), with overrides per skill. Model and effort for picks which reviewer's values the form shows. First match wins: what you tell the agent in chat · workspace, this skill · workspace · global, this skill · global · the reviewer's default model and effort high. Model lists come from codex debug models and agy models (kept in ~/.cross-review/models.json and models-agy.json, so Settings opens at once while it asks again); Claude Code shows its aliases, and Other… takes a full model name.
- Follow reviews: when on, every review that starts opens its page in your browser, starting the dashboard if it is not running; that dashboard closes itself after 30 minutes with no page open.
- Follow plans: when on, each plan
loop-plan finishes opens on its Plan tab the same way, so you can read it before you approve it.
- Plans in git: off by default. On adds an exception for
plans/ to .cross-review/.gitignore, so loop-implement commits the plan with each phase; sessions and settings stay out of git. A root .gitignore that ignores .cross-review/ itself overrides that exception: change it to .cross-review/* and add !.cross-review/plans/ (the dashboard and loop-plan warn when this happens). Turning it off later does not remove plans already committed: run on them.
The server listens on 127.0.0.1 only. The link it prints carries a per-run token that every request needs, so other web pages cannot read your sessions or change settings.
License
MIT
