Definition
Plain language
The clickable, windowed interface most computer programs show their users.
As stated in the literature
Graphical User Interface — the visual, pointer-driven interaction surface of an application, distinct from CLI; the target of computer-use agents like Browser-Use and ToolCUA.
Why it matters: Most software in the world only has a GUI, so agents that can drive them open up automation for tasks that don't expose APIs.
For example, a computer-use agent has to click the right button in a desktop app's GUI, which means it needs to actually see and interpret the screen.
Heard on the show
“When one builder figures out that some multi-service web stack needs readiness polling before its GUI will launch, that lesson gets written down and becomes the default for every subsequent web stack.”Episode 017 — When the Agent Grades Its Own Homework: A Brutal New Benchmark for AI Workers