MCP - Developer built a read-only MCP server to query

The folding roof on my Ford Focus CC stopped working. Roof module: zero fault codes. Door module: two codes. I built a read-only MCP server that lets Claude query the car's diagnostics directly. Here's what worked, what didn't, and where I wasted hours. Source: https://x.com/patek_petr/status/2056714999452545176