1@README.md 2 3- Build and run through the devshell: `nix develop -c buck2 run //apps/<name>:<name> -- <args>`. 4- The toolchain builds at opt-level 3 for every target (`../toolchains/BUCK` 5 says why). Do not add a per-app debug variant to "speed up the build": the 6 core runs below real time unoptimised. 7- Everything an app writes goes under `run/` (gitignored), never anywhere 8 tracked and never the repo root.