I run Qwen3-Coder on a spare RTX 5090 and point my coding agent at it over the LAN. Private, fast, no per-token bill, secured with an API key, and watched on a dashboard. Here is the whole build.

I run my place off an underground cistern, and a dry run can boil the pump and flood the basement. Here is the whole chain that put the tank on a dashboard, from the 4-20mA probe to the gallons reading on my phone.