AREPL is a VS Code extension that evaluates Python code in real-time as you type, displaying variables, errors, and print output in a side panel. It provides a scratchpad-like experience for Python development, with features like real-time evaluation, variable inspection, error display, and support for dumping variables from functions. The extension uses a Python backend (arepl-backend npm package) to execute code and communicate results via JSON. The TypeScript architecture includes a PreviewManager that orchestrates execution and preview updates, a PreviewContainer that manages the webview, and separate modules for inline errors (PythonInlinePreview) and panel display (PythonPanelPreview). The codebase is well-structured with clear separation of concerns, includes unit tests (mocha), and uses telemetry for diagnostics. The extension is maintained (last release November 2024) and uses modern dependencies.