There is no open-source tool that automatically checks a hobbyist's schematic for missing bypass capacitors, wrong pull-up resistor values, or unconnected IC power pins — KiCad's ERC only checks net connectivity

KiCad's Electrical Rules Check (ERC) verifies that nets are connected, that pins marked as outputs aren't shorted together, and that power flags exist. It does not check whether a microcontroller's VCAP pin has the required 2.2uF capacitor to ground, whether an I2C bus has pull-up resistors (and whether they're the right value for the bus speed and capacitance), whether an LDO regulator has the minimum output capacitance specified in its datasheet, or whether a MOSFET gate driver has a series resistor to limit ringing. These are the errors that actually cause boards to fail, and they pass ERC with zero warnings. This gap means that a hobbyist's first custom PCB — the one they spent weeks designing and $30-50 fabricating and assembling — has a high probability of not working due to a 'known unknown' that any experienced EE would catch in a 5-minute schematic review. But hobbyists don't have access to experienced EEs. Online schematic review requests on Reddit's r/PrintedCircuitBoard or the EEVBlog forum can take days to get responses, and the feedback quality varies wildly. The result is an expensive, time-consuming trial-and-error loop: order board, discover it doesn't work, post for help, learn you're missing a bypass cap, redesign, reorder, wait 2 more weeks. The structural reason this gap exists is that 'electrical correctness' beyond net connectivity requires component-specific domain knowledge — you need to know that the STM32F4's VCAP pin needs exactly 2.2uF, not just 'a capacitor.' Encoding this knowledge into automated rules requires a massive database of component-specific design requirements extracted from datasheets, which is a data problem no open-source project has tackled at scale. Emerging AI-powered tools like Schemalyzer and Traceformer are attempting this, but they're commercial, cloud-based, limited to specific EDA tools, and not yet integrated into the design workflow where hobbyists would benefit most — inside KiCad's own DRC engine, flagging issues before the board is sent to fab.