Code Review by anthropics

Automated code review for pull requests using multiple specialized agents with confidence-based scoring to filter false positives.

Overview

The Code Review Plugin automates pull request review by launching multiple agents in parallel to independently audit changes from different perspectives. It uses confidence scoring to filter out false positives, ensuring only high-quality, actionable feedback is posted.

Commands

/code-review

Performs automated code review on a pull request using multiple specialized agents.

What it does:

1. Checks if review is needed (skips closed, draft, trivial, or already-reviewed PRs)
2. Gathers relevant CLAUDE.md guideline files from the repository
3. Summarizes the pull request changes
4. Launches 4 parallel agents to independently review:

• Agents #1 & #2: Audit for CLAUDE.md compliance
• Agent #3: Scan for obvious bugs in changes
• Agent #4: Analyze git blame/history for context-based issues

1. Scores each issue 0-100 for confidence level
2. Filters out issues below 80 confidence threshold
3. Posts review comment with high-confidence issues only

Usage:

/code-review

Example workflow:

# On a PR branch, run:
/code-review

# Claude will:
# - Launch 4 review agents in parallel
# - Score each issue for confidence
# - Post comment with issues ≥80 confidence
# - Skip posting if no high-confidence issues found

Features:

• Multiple independent agents for comprehensive review
• Confidence-based scoring reduces false positives (threshold: 80)
• CLAUDE.md compliance checking with explicit guideline verification
• Bug detection focused on changes (not pre-existing issues)
• Historical context analysis via git blame
• Automatic skipping of closed, draft, or already-reviewed PRs
• Links directly to code with full SHA and line ranges

Review comment format:

## Code review

Found 3 issues:

1. Missing error handling for OAuth callback (CLAUDE.md says "Always handle OAuth errors")

https://github.com/owner/repo/blob/abc123.../src/auth.ts#L67-L72

2. Memory leak: OAuth state not cleaned up (bug due to missing cleanup in finally block)

https://github.com/owner/repo/blob/abc123.../src/auth.ts#L88-L95

3. Inconsistent naming pattern (src/conventions/CLAUDE.md says "Use camelCase for functions")

https://github.com/owner/repo/blob/abc123.../src/utils.ts#L23-L28

Confidence scoring:

• 0: Not confident, false positive
• 25: Somewhat confident, might be real
• 50: Moderately confident, real but minor
• 75: Highly confident, real and important
• 100: Absolutely certain, definitely real

False positives filtered:

• Pre-existing issues not introduced in PR
• Code that looks like a bug but isn't
• Pedantic nitpicks
• Issues linters will catch
• General quality issues (unless in CLAUDE.md)
• Issues with lint ignore comments

Installation

This plugin is included in the Claude Code repository. The command is automatically available when using Claude Code.

Best Practices

Using /code-review

• Maintain clear CLAUDE.md files for better compliance checking
• Trust the 80+ confidence threshold - false positives are filtered
• Run on all non-trivial pull requests
• Review agent findings as a starting point for human review
• Update CLAUDE.md based on recurring review patterns

When to use

• All pull requests with meaningful changes
• PRs touching critical code paths
• PRs from multiple contributors
• PRs where guideline compliance matters

When not to use

• Closed or draft PRs (automatically skipped anyway)
• Trivial automated PRs (automatically skipped)
• Urgent hotfixes requiring immediate merge
• PRs already reviewed (automatically skipped)

Workflow Integration

Standard PR review workflow:

# Create PR with changes
/code-review

# Review the automated feedback
# Make any necessary fixes
# Merge when ready

As part of CI/CD:

# Trigger on PR creation or update
# Automatically posts review comments
# Skip if review already exists