A small toolbox, pinned and reproducible. Nothing here is fashionable for its own sake, each line earns its slot because it makes the result more deterministic, more auditable, or more honest about where the time goes.
rustc is the default: the borrow checker buys us correctness we'd otherwise pay for in 3am pages. zig comes out when Rust's safety gets in the way of a tight allocator or a freestanding target, comptime and no hidden control flow make it the right tool for the hot, unsafe corners. clang 19 handles the kernel modules and embedded firmware where the toolchain isn't negotiable.
linux 6.9 is the target we test against, we pin the kernel because scheduler and io_uring behavior shifts between releases and we'd rather know. nix gives us builds that are byte-identical on your machine and ours, so "works here" stops being a category of bug. postgres 17 is what we reach for when a real database is genuinely fine, we don't write a custom store to prove a point.
tla+ 1.8 specifies the protocols and state machines that have to survive a decade, a model checker catches the race you'd never reproduce in a test. perf and ebpf are the truth machine: when we claim a speedup, it's because the flamegraph and the counters agree, not because the microbenchmark felt faster.
$ uname -a Linux build-rig 6.9.0-nexora #1 SMP PREEMPT_DYNAMIC x86_64 GNU/Linux $ nproc / mem cores: 16 (AMD Zen4) · ram: 64G ECC · swap: off (we don't page hot paths) $ toolchain rustc 1.84.0 · zig 0.13.0 · clang 19.1.0 · nix 2.20.5 $ reproducibility flake.lock pinned · SOURCE_DATE_EPOCH frozen · CI rebuilds bit-for-bit $ [wrn] locale set to C.UTF-8, yes, on purpose $ [ok] environment hash matches lockfile · ready to build