It scrolls up

My son and daughter stand around a physical VT520 terminal from DEC, asking it questions as if it were a real person. My son has been listening to the Harry Potter books on tape. Naturally, he asks about things he's curious about from the story.

The tactile buttons click as they type. A question appears on the monochrome display. A text response follows and scrolls up.

The VT520 provides the display and keyboard. The text reaches it from my Linux machine over a serial connection.

Getting away with less

OpenCode Mini / interface 80 × 25

OpenCode
~/src/notes/setup
Ask anything... "Fix a TODO in the codebase"

A small interface. The session opens with a splash, the working directory, and an empty prompt.

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On that machine, OpenCode Mini renders to the normal scrollback buffer rather than the alternate screen used by the full terminal UI. Its interface has a simple CLI feel.

A small bar at the bottom can show some context about the prompt or session, but not much more. The contents become the main part of the screen.

I started by making this version look almost exactly like the full terminal interface. That way, people would recognize the product.

For each UI element, I asked if it added value. Did it have to be present all the time, or could it stay hidden until you asked for that information? The settings panel leaves some of that choice to you. It lets you decide how much information is enough.

The more I iterated, the more I removed. I started with the background color, then removed UI elements step by step. What remained was the scrollback, a prompt, a bottom bar, a splash screen, and some context about the session.

A physical terminal

OpenCode Mini / monochrome 80 × 25

[O] OpenCode
    ~/src/notes/setup
Ask anything... "Fix a TODO in the codebase"

ASCII from the start. Monochrome mode replaces interface symbols with ASCII from the first screen.

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Terminals never really disappeared. They changed into software emulators. Even the VT520 can emulate different terminals. Terminal applications have had a renaissance. Coding agents have made terminal applications popular again.

The largest language models usually run in data centers, much like mainframes once sat in one location with terminals connected to them.

Coding agents normally run inside modern graphical terminal emulators, but I ran this one through a physical terminal instead: a VT520 with a monochrome, paper-white CRT and a keyboard on the end of a serial line.

I set the display to 80 columns and 25 lines. The text stream, scrollback, and prompt still work. The hardware does not support Unicode symbols, color, or mouse interactions.

A monochrome mode in the settings replaces interface symbols with ASCII and converts the output to ASCII before it enters the scrollback.

A physical terminal. The CRT and keyboard provide the interface. The application runs on Linux at the other end of the serial connection. Turn on the sound to hear the keys.

Terminal interfaces are often limiting, yet powerful. You can still use this minimal interface to do real work.

The full experience shows much more. On a physical terminal, the same application can look as simple as a prompt.

The tactile buttons click as my son and daughter type another question.