Claw Code vs Libretto

On March 31, 2026, a security researcher discovered that Anthropic had accidentally published full Claude Code source maps to npm — making the entire internal architecture readable to anyone who looked. Within hours, a developer going by ultraworkers began a clean-room rewrite in Rust, and Claw Code was born. The project hit 180,000 GitHub stars in under two weeks, making it one of the fastest-growing open-source repositories in history. It replicates Claude Code's core agent loop, permission system, and tool dispatch while adding a Rust-native performance profile and removing telemetry. The project explicitly operates under clean-room principles — contributors who viewed the source maps are excluded from contributing. The implications are significant: Claw Code is proof that the underlying architecture of agentic coding tools is now commoditized. If Anthropic's secret sauce was the agent loop, that loop is now public. What remains is the model quality — and Claw Code works with any API-compatible provider.

Libretto is an open-source TypeScript toolkit for building and maintaining browser automations that are actually reliable. Unlike most AI-driven browser tools that use probabilistic reasoning to select elements at runtime, Libretto works by having the AI generate deterministic selectors and action sequences upfront — then executing them with zero LLM involvement at runtime. The AI is your authoring tool, not your runtime dependency. The core insight: most AI browser automations fail in production because they call an LLM on every page interaction. Libretto flips this by using AI to write and update the automation scripts, but running them as ordinary code. When a site changes and your automation breaks, Libretto detects the failure and prompts you to let AI update the selector — then it's deterministic again. Built by the team at Saffron Health, the library hit HN's front page today and is generating discussion as a more pragmatic alternative to fully autonomous browser agents. For anyone who's tried Playwright with AI wrappers and found them unreliable in CI/CD, this is the architecture that's been missing.