Libretto vs TUI-use

Libretto is an open-source browser automation toolkit built by Saffron Health to solve a critical problem with AI-driven web agents: non-determinism. Standard agent-controlled browsers using Playwright or Puppeteer routinely fail 20-30% of the time on production workflows because they rely on LLM judgment for timing and element selection. Libretto replaces that with a record-replay system that captures precise interaction timing and DOM fingerprints, achieving a reported 95% success rate on identical workflows. The library works by recording a "golden path" of a browser session — capturing not just actions but the exact CSS selectors, visual context, and timing windows during which those actions are valid. On replay, it verifies each step against expected page state before proceeding, and falls back to an LLM-assisted recovery mode when pages drift (e.g., after a UI update). Saffron Health built it to maintain integrations with EHR portals that change frequently and where failure has compliance consequences. Saffron open-sourced Libretto after using it internally for 18 months across 40+ healthcare software integrations. The HN thread highlighted the appeal for fintech, legal, and healthcare automation where reliability, not just capability, is the product. The toolkit targets TypeScript/Node.js environments and integrates cleanly with existing Playwright infrastructure.

TUI-use is an open-source library that gives AI agents the ability to interact with traditional interactive terminal (TUI) applications — think vim, htop, ssh sessions, database CLIs, and legacy text-based UIs that were never designed for programmatic control. Instead of requiring a GUI or a REST API, TUI-use interprets terminal output as structured state and sends synthetic keystrokes back, enabling agents to "see" and "drive" any TUI application as if they were a human at a keyboard. The project was born from a real pain point: AI coding agents can call bash commands and write files, but they fail badly the moment a tool opens an interactive prompt waiting for user input. TUI-use solves this by building a state machine layer over PTY (pseudo-terminal) interfaces, letting agents read the current screen buffer, detect interactive prompts, and respond intelligently. It ships with adapters for common TUI patterns and a clean API that works with any LLM tool-use framework. The Show HN post attracted genuine interest from the ops and DevOps community — many existing workflows depend on tools that expose only an interactive terminal interface. TUI-use fills a real gap in the "AI agents that control computers" space by handling the long tail of CLI programs that have no API, no GUI, and no intention of ever getting one.