Circuits are defined in declarative code (the 'ato' language) rather than a graphical CAD tool, so an agent can build, simulate, and inspect failures without leaving the project. Each task uses real manufacturer parts with datasheet-derived specifications, and grading cuts power, changes component tolerances, and re-runs SPICE simulations to check whether the design survives real-world conditions — not just whether it compiles. As of EEBench V1 (September 2026), it covers analog and digital design through simulation only, not PCB layout, routing, or manufacturing.