Open Code Review: How Alibaba Open-Sourced an AI Code Reviewer That Cuts Token Costs by 90%

Alibaba open-sourced Open Code Review (ocr), a tool for automatic pull request review used internally for two years. Its hybrid architecture with a deterministic engine and AI agents cuts token usage by about 9x (89%) and improves comment positioning accuracy.

• Tool used internally at Alibaba for two years by tens of thousands of developers
• Token usage cut by about 89% compared to general-purpose agents
• AACR-Bench: 200 PRs, 10 languages, 1505 defects from 80+ engineers
• Installs via npm as CLI, supports OpenAI, Anthropic, and local models