Reduction levels

How Fuse shrinks C# from light cleanup to aggressive compression and signature-only skeletons, and how to pick the smallest level that answers the task.

Reduction is how Fuse shrinks content without changing what it means. It runs as a ladder: each level builds on the one before, trading more of the source for fewer tokens. Pick the smallest level that still answers your task.

The ladder

Level	Command	Removes	Use it when
Default	`fuse dotnet --directory ./src`	Whitespace and blank lines; minifies XML and Razor	Every fusion, a safe baseline
Individual removals	`--remove-csharp-comments --remove-csharp-usings`	Selected categories: comments, usings, namespaces, regions	Trim noise but keep structure
Aggressive	`--aggressive`	The removals plus attributes, `this.`, property whitespace	Maximum reduction with bodies intact
All	`--all`	Every C# reduction at once	One switch for full compression
Skeleton	`--skeleton`	Method bodies; signatures only	An architecture pass on an unfamiliar solution

Default

The baseline does lossless cleanup: it normalizes whitespace, condenses blank lines, and minifies XML-family and Razor files. It runs on every fusion.

Individual removals

Each category has its own flag, so you can keep what you need:

--remove-csharp-comments removes line and block comments, preserving string contents.
--remove-csharp-usings removes using directives and aliases.
--remove-csharp-namespaces removes namespace declarations and their indentation.
--remove-csharp-regions removes #region markers and preprocessor directives.

Aggressive

--aggressive runs the standard removals and then a second tier: it strips noise attributes such as DebuggerDisplay and MethodImpl, removes the this. prefix, rewrites auto-properties to a compact form, and collapses whitespace around delimiters. It preserves string-literal contents, but the output is no longer guaranteed to compile. Use it when the reader is a model that needs the logic, not a compiler.

All

--all enables the full standard removal set together with aggressive mode and generated-code collapse in one switch. On the benchmark corpus it removes 21 to 40 percent of tokens at 99 to 100 percent type and method fidelity, which makes it the dependable cut.

Skeleton

--skeleton drops method bodies entirely and emits class, interface, and method signatures only. It is the deepest cut, 66 to 93 percent on the corpus, and it is an architecture map, not a substitute for the source. On a codebase with heavy conditional compilation the regex skeleton can lose signatures; the precision tier fixes that.

Reduction is not deletion

The default and --all levels are designed to keep the public API. An independent Roslyn oracle confirms 99 to 100 percent of public types and methods survive, and fuse verify reports the preserved surface for any run. Skeleton makes no claim of body fidelity, by design: it keeps signatures and drops bodies.

Survey before you reduce

When you only need a map, the table-of-contents survey is cheaper still:

fuse dotnet --directory ./src --toc

--toc emits a directory tree with a per-file symbol outline and token cost instead of file bodies. See Survey a codebase cheaply.

The exact transforms each reducer performs are in the Reducers reference. To narrow which files get reduced at all, see Scoping.