Using Codex CLI with gpt-oss:120b on an NVIDIA DGX Spark via Tailscale

I've written about the DGX Spark before. Here's how I got OpenAI's Codex CLI to run on my Mac against a gpt-oss:120b model running on the DGX Spark via a Tailscale network. Setting up Tailscale I installed Tailscale on the Spark a while ago and didn't make detailed notes. The Spark runs Ubuntu so I followed the Tailscale Linux installation instructions . My Mac is signed into Tailscale as well. I…