| name | fantomas-lint |
| description | Ensure F# source code is formatted cleanly with Fantomas before finishing a task. Use when writing or editing any F# source file, before committing changes, or when CI lint failures need to be fixed. Run Fantomas to reformat, then verify tests still pass. |
Fantomas Lint Check
CI runs Fantomas to enforce consistent F# formatting. Any diff that introduces
formatting violations will fail the lint step, even if all tests pass.
Steps
Always perform these steps after editing F# source files, before considering a
task complete:
1. Reformat with Fantomas
Run the repo reformat script from the workspace root:
bash reformat.sh
This restores the .NET local tools, runs fantomas on the whole workspace, and
runs dotnet format. It is safe to re-run; it is idempotent when the code is
already clean.
Alternatively, to just check without modifying files (matches the CI check):
dotnet tool restore
dotnet tool run fantomas --check .
If --check reports violations, run bash reformat.sh to fix them.
2. Verify tests still pass
dotnet test
Both steps must succeed before the task is done.
Notes
- Fantomas is a .NET local tool declared in
.config/dotnet-tools.json; always
run dotnet tool restore before invoking it directly.
- The VS Code task reformat (defined in
.vscode/tasks.json) runs
bash reformat.sh and can be used instead of the terminal command.
- Do not skip the reformat step even for small one-line edits — Fantomas enforces
indentation, blank lines, and spacing rules that are easy to violate by hand.
