Lucas Gerads wired his LeCroy oscilloscope and a SPICE simulator to custom MCP servers so Claude Code could iterate between simulation and real hardware. By exposing the instruments through HTTP‑based MCP endpoints, the LLM receives fresh measurements instead of static snapshots. The demo uses a trivial MCU circuit, but the setup proves the concept scales to larger embedded projects.

Gerads found natural‑language prompts work for simple schematics but quickly break down on anything beyond a few components. Supplying Claude with live data let it validate SPICE models, normalize time axes, and align waveforms without manual eyeballing. He also bundles a Makefile that defines build, flash, ping and erase commands, forcing the model to call deterministic tooling rather than inventing ad‑hoc shell strings.

Key takeaways include never letting Claude assume wiring, always feeding it fresh measurements, and storing raw traces in files rather than dumping them directly into the prompt. Providing an explicit pinout and a scripted build flow keeps the interaction reliable. The open‑source repos—leCroy-mcp, spicelib-mcp, and rc-filter-demo-files—showcase the end‑to‑end pipeline and invite others to adopt the loop for more ambitious hardware designs.