After the Claude Code source leak, instead of digging through feature flags and anti-distillation defenses, I focused on what I could ship. I focused on reverse-engineering Claude in Chrome from its MCP tool schemas. Clean room, not a fork.
Claude in Chrome blocks 58 domains. Banks, Tinder, Reddit, Robinhood, Bloomberg. Also only works in Chrome and Edge. open-claude-in-chrome has none of that.
Same 18 tools, same performance. Claude doesn't know the difference because it was trained on these exact schemas.
Stuff I found running both extensions side-by-side:
- The official forces deviceScaleFactor: 1 via CDP. Without this, Retina displays make every click miss. Spent an afternoon staring at window.devicePixelRatio to figure that one out.
- It doesn't return screenshots on clicks or typing. Only on screenshot and scroll. I was returning one on every action and burning through the 20MB API limit in 15 calls.
SebastianSosa•1h ago
Claude in Chrome blocks 58 domains. Banks, Tinder, Reddit, Robinhood, Bloomberg. Also only works in Chrome and Edge. open-claude-in-chrome has none of that.
Same 18 tools, same performance. Claude doesn't know the difference because it was trained on these exact schemas.
Stuff I found running both extensions side-by-side:
- The official forces deviceScaleFactor: 1 via CDP. Without this, Retina displays make every click miss. Spent an afternoon staring at window.devicePixelRatio to figure that one out.
- It doesn't return screenshots on clicks or typing. Only on screenshot and scroll. I was returning one on every action and burning through the 20MB API limit in 15 calls.
Case study on how I built it: https://www.noemica.io/blog/reverse-engineered-claude-in-chr...