With ZERO_FORMAT_ON_WRITE=1, a successful edit/write runs the language's
community-standard formatter on the file (gofmt, rustfmt, ruff, prettier,
zig fmt, dart format, terraform fmt, shfmt, clang-format, ktlint,
swiftformat, stylua, gleam format — 27 extensions), so model output
always lands in project-canonical style and never fails a format check
it cannot see. Best-effort: missing binary, error, or 10s timeout leaves
the unformatted write standing. Off by default per house convention —
auto-reformatting changes bytes the model did not write.
Ordering is load-bearing: formatting runs BEFORE the FileTracker
re-baseline so the recorded content matches what the formatter left on
disk; baselining pre-format content would make the very next edit trip
the external-modification conflict guard (covered by test).
Co-Authored-By: Claude Fable 5 <[email protected]>
