The developer created CoPet, a desktop application for Windows that visualizes the activity of the Codex AI agent. The program displays a pixel-art satellite that changes its state based on the agent's tasks, such as thinking, using tools, or compacting context.
The project began in January 2026. The initial prototype was developed in three to four hours using C# and .NET. The first version relied on OpenTelemetry and a JSON file to track agent states, but by February 22, 2026, the architecture was simplified into a single process.
The animation system consists of 56 frames, each 128 by 128 pixels. The satellite's movements, such as unfolding solar panels or extending an antenna, are triggered by specific events from the AI agent. The developer designed the logic to ensure smooth transitions between animation cycles.
To manage development remotely, the creator implemented a tool called MediaLab. It allows the AI agent to generate and send images of the interface and animation sequences directly to the developer's phone, enabling code review and approval while commuting.
