The build time claim in the blog post is dubious, part of the problem is CGO isn't fast, but also if build time was really a motivator the null build path is entirely unoptimized for objects with long build times:

cached null (no changes) build:

        ~github/unstablebuild/rune % make
        pre-commit not installed; skipping git hook setup
        cd cmd/buildstamp && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/buildstamp
        cd cmd/extension_chaos && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_chaos
        cd cmd/extension_color_palette && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_color_palette
        cd cmd/extension_fuzzy_search && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_fuzzy_search
        cd cmd/extension_go && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_go
        cd cmd/extension_python && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_python
        cd cmd/extension_rtc && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_rtc
        cd cmd/extension_rust && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_rust
        cd cmd/extension_zig && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/extension_zig
        cd cmd/runefox && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/runefox
        cd cmd/sshshop && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/sshshop
        cd cmd/walkbench && CGO_ENABLED=1 go build  -ldflags="-X unstable.build/rune/internal/debug.Tag=$(git describe --tags) -X unstable.build/rune/internal/debug.Commit=$(git rev-parse --short HEAD) -X unstable.build/rune/internal/debug.BuildDate=2026-09-11T20:16:22Z  -X unstable.build/rune/internal/debug.Package=six" -o ../../bin/walkbench
        make  35.90s user 5.88s system 191% cpu 21.846 total 1975848 rss

vs. cached non-null (changed) build:

    ~github/zed-industries/zed % touch crates/zed/src/zed.rs
    ~github/zed-industries/zed % cargo build
       Compiling zed v1.18.0 (/home/raggi/src/github.com/zed-industries/zed/crates/zed)
       Finished `dev` profile [unoptimized + debuginfo] target(s) in 8.42s
    cargo build  10.15s user 9.34s system 228% cpu 8.531 total 7930312 rss

Build times are a valid thing to care about and talk about, but the claims implied don't stand up to scrutiny.

Rune is now open source