GHI Electronics has released a Visual Studio Code extension that brings full source-level, on-chip debugging to MicroPython, no special hardware required. You use the same USB cable already connected to your board. Supported targets include Raspberry Pi Pico variants and several ESP32 chips, including the ESP32-S3.
The catch is firmware. You must flash a custom MicroPython image, either one GHI provides or one you build yourself. Building your own means assembling a full toolchain and its dependencies. The provided images have known issues: an RP2040 GEEK board threw setup errors, and Linux users targeting the ESP32-S3 hit similar behavior. A stock Pico worked cleanly. Documented limitations include no exception interception for already-caught exceptions and breakpoints that halt all threads simultaneously.
Read the full piece for the specific GitHub issue list and to understand where the boundaries of this tool actually sit. The larger question it opens is why MicroPython still lacks a native debugger after all this time, and what it costs to bolt one on from the outside.
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