multi-agent-review

Automated PR reviews by Claude Code for commits made by Codex and other AI agents. Like CodeRabbit, but for agent-to-agent code review.

Flow: Codex writes code → pushes a PR → Claude Code reviews it → posts a structured GitHub PR review with inline comments.

Quick Start

npm install -g multi-agent-review

cd your-project
mar init

# Reviews happen automatically when Codex finishes a turn.
# Or run manually:
mar review codex/my-feature

Prerequisites

• Node.js >= 20
• Claude Code CLI (claude command)
• GitHub CLI (gh command, authenticated)
• Codex CLI (optional, for automatic reviews)

How It Works

1. mar init sets up your project:

   • Creates .mar/config.json with detected repo and branch defaults
   • Adds a notify hook to ~/.codex/config.toml so Codex triggers reviews automatically
   • Adds .mar/ to .gitignore

2. When Codex finishes a turn, the notify handler checks:

   • Is the branch a codex/* branch? (configurable pattern)
   • Are there new commits since the last review?
   • Is there an open PR for this branch?
   • If all yes: spawns a background review

3. The review runs claude -p with a structured review prompt:

   • Reads the cumulative diff against the base branch
   • Analyzes for security issues, bugs, performance problems, convention violations
   • Returns structured JSON with findings

4. Posts to GitHub as a proper PR review:

   • Summary with verdict and collapsible file walkthrough
   • Inline comments on specific diff lines with severity badges
   • Uses COMMENT event (advisory only, never blocks merges)
   • Updates existing review instead of posting duplicates

GitHub Action

Add Claude reviews to any repo without installing the CLI:

# .github/workflows/review.yml
name: Claude Review
on: pull_request

jobs:
  review:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - uses: TheCraigHewitt/multi-agent-review@v1
        with:
          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}

Action Inputs

Input	Description	Required	Default
anthropic_api_key	Anthropic API key	Yes	—
model	Claude model to use	No	claude-sonnet-4-6
max_diff_lines	Diff truncation limit	No	5000

Action Outputs

Output	Description
verdict	Review verdict (clean, minor_issues, major_issues, critical)
findings_count	Number of findings

Commands

mar init

Initialize in the current git repository. Detects the GitHub remote and base branch automatically.

mar review [branch]

Review a specific branch (defaults to current branch). Requires an open PR.

mar review codex/add-auth

# Preview review locally without posting to GitHub
mar review codex/add-auth --dry-run

mar status

Show current configuration and recent review history.

mar notify-handler [payload]

Called automatically by Codex via the notify hook. Not intended for manual use.

Configuration

After mar init, edit .mar/config.json:

{
  "repo": "owner/repo",
  "baseBranch": "main",
  "branchPattern": "codex/*",
  "model": "sonnet",
  "reviewPrompt": null,
  "maxDiffLines": 5000
}

Field	Description	Default
repo	GitHub owner/repo	Auto-detected
baseBranch	Branch to diff against	Auto-detected
branchPattern	Glob pattern for branches to review	codex/*
model	Claude model to use	sonnet
reviewPrompt	Path to custom review prompt	null (uses built-in)
maxDiffLines	Truncate diffs longer than this	5000

Custom Review Prompt

Place a .mar/review-prompt.md in your project to override the default review prompt. The prompt receives the diff via stdin and should instruct Claude to return JSON matching the review schema.

Review Output

PR reviews include a summary comment:

## Code Review

**Verdict:** Minor issues found (2 findings)

**Summary:** Adds token validation to the auth flow and updates session access control.

<details>
<summary>Walkthrough (3 files changed)</summary>

| File | Change |
|------|--------|
| `src/routes/auth.ts` | Add Zod validation for token exchange |
| `src/services/token-service.ts` | Extract token parsing helper |
| `src/routes/__tests__/auth.test.ts` | Add malformed token tests |

</details>

And inline comments on specific lines:

**warning** Missing input validation on the token parameter.

\`\`\`suggestion
const token = z.string().min(1).parse(req.body.token);
\`\`\`

License

MIT