TUI Validate

Overview

This skill validates Terminal User Interface (TUI) applications by capturing their output and using LLM-as-judge for semantic validation. It leverages freeze from Charmbracelet for high-fidelity terminal screenshots and provides structured validation criteria.

Philosophy: Rather than brittle string matching, this skill uses semantic understanding to validate that TUI output "looks right" - checking layout, content presence, and visual hierarchy without breaking on minor formatting changes.

When to Use

• Validating TUI rendering after changes
• Checking that UI components display correctly
• Visual regression testing for terminal applications
• Verifying TUI state after specific interactions
• Creating documentation screenshots with validation

Prerequisites

Required:

• freeze CLI tool installed (brew install charmbracelet/tap/freeze)
• tmux for interactive TUI capture (optional, for live applications)

Verification:

# Check freeze is installed
freeze --version

# Check tmux is installed (for interactive capture)
tmux -V

Parameters

• target (required): What to validate. One of:

  • file:<path> - ANSI output file to validate
  • command:<cmd> - Command to execute and capture
  • tmux:<session> - Live tmux session to capture
  • buffer:<text> - Raw text/ANSI to validate

• criteria (required): Validation criteria. Can be:

  • A predefined criteria name (see Built-in Criteria)
  • A custom criteria string describing what to check

• output_format (optional, default: "svg"): Screenshot format

  • svg - Vector format, best for documentation
  • png - Raster format, best for visual diff
  • text - Text-only extraction, fastest

• save_screenshot (optional, default: false): Whether to save the screenshot

  • If true, saves to {target_name}.{format} in current directory