Buck2 project root. The prelude is BUNDLED with the buck2 binary (via [external_cells]) so it always matches the version in the nix devshell — a checked-in prelude drifts and breaks with "attribute not available" the day the binary and the prelude disagree. Cargo.toml is the dependency source of truth; reindeer generates third-party//rust from it.
nyx has 10 cores. Leave one idle so the host (WSLg, the window, the user's desktop) stays responsive while several agents build (user, 2026-09-22).
28threads = 9
Record when each artifact in buck-out was last used, so that
buck2 clean --stale <age> can prune old build variants without a full
rebuild. Without it, stale-clean finds nothing, and deleting variants by
hand desyncs the daemon (2026-09-22: a hand prune broke a build-script
output the daemon still believed materialized).