---
title: Why not just dotnet format?
description: What Curb adds on top of dotnet format, and where the two deliberately agree.
url: https://docs-v3-preview.elastic.dev/why-not/dotnet-format
---

# Why not just dotnet format?
`dotnet format` is the right answer for teams that want IDE0055 formatting enforced as part of the
build. Curb agrees with it — by design and by measurement — and adds on top.

## What dotnet format does

`dotnet format whitespace` implements all 39 `csharp_*` and `dotnet_*` formatting options from IDE0055.
It normalises indentation, spacing, braces, and a dozen other whitespace decisions. It is the reference
implementation.
What it does not do: wrap long lines. IDE0055 has no opinion about line width, so `dotnet format` has
none either.
`dotnet format style` adds semantic code style — `var` decisions, naming conventions, unused member
detection. It loads a compilation to do this, which costs roughly 40 seconds per project in a large
solution.

## What Curb adds

- Reflow. Add `max_line_length = 120` to your `.editorconfig` and Curb wraps long lines. `dotnet format` never will.
- Syntax-level code style without a compilation. Several IDE analysers — IDE0011 (braces), IDE0022–0027 (expression bodies), IDE0036 (modifier order), IDE0065 (using placement), IDE0161 (file-scoped namespaces) — need a compilation in `dotnet format style` but are decidable from syntax alone. Curb applies them in the same pass as layout.
- ReSharper formatting keys. The `csharp_wrap_*`, `csharp_place_*`, `csharp_blank_lines_*` and `csharp_trailing_comma_*` families are read by Rider but not by `dotnet format`. Curb honours them.
- Speed. About 15× faster at the same task, on the same files. That gap is what makes running inside every build viable rather than as a separate step. See [performance](https://docs-v3-preview.elastic.dev/design-principles/performance).


## Where they agree

Curb's output is a fixed point of `dotnet format whitespace`. That is a CI-gated measurement, not a
claim: run `dotnet format` over Curb's output and nothing changes. The two tools will never fight
each other in a repository that uses both. Format Document in the IDE won't undo what Curb wrote.
With reflow off, the match is 100%. With reflow on and deterministic layout, also 100%. With reflow on
and `csharp_keep_existing_linebreaks = true`, 99.9% — one file, a property pattern, measured and held.

## Running together

The build integration ([workflow/msbuild.md](https://docs-v3-preview.elastic.dev/workflow/msbuild)) puts Curb at
`BeforeTargets="CoreCompile"`. When `EnforceCodeStyleInBuild` is set, the IDE analysers run inside
`CoreCompile` and report whatever Curb could not fix — the semantic remainder. The two tools
complement each other rather than duplicating work.