Code broken after an upgrade? → diff --package Foo@old..new first (classifies breaking/additive), then member to see the new API
What's new in a .NET preview? → diff --platform System.Runtime@P2..P3 --additive per framework library
What types are in this package? → type --package Foo (discover), find (search by pattern)
What members does a type have? → member Type --package Foo (compact table, docs on by default)
What does a type look like? → type Type --package Foo (tree view for single type)
What are the method signatures? → member Type --package Foo -m Method (full signatures + docs)
What is the source/IL? → member Type --package Foo -m Method:1 -v:d (Source, Lowered C#, IL)
Where is the source code? → source Type --package Foo (SourceLink URLs); add -m Member for line numbers; --cat fetches and prints the file contents
What constructors exist? → member 'Type<T>' --package Foo -m .ctor (use <T> not <>)
How many overloads? → member Type --package Foo --show-index (shows Name:N indices)
What extends this type? → extensions (extension methods/properties; --reachable for transitive)
What implements this interface? → implements (concrete types)
What does this depend on? → depends (type hierarchy, --package deps, or library refs); --mermaid for a diagram
What version/metadata does this have? → package / library; Foo --version (cache-first), Foo --latest-version (always NuGet), Foo --versions (list all)
What TFMs are available? → package Foo --tfms, then type --package Foo --tfm net10.0
What metadata fields exist? → -S Section --fields "PDB*" (structured query, no DSL)
Show me something cool → demo (curated showcase queries)

Key Patterns

Default output is markdown — headings, tables, and field lists that render well in terminals, editors, and LLM contexts. No flags needed:

dnx dotnet-inspect -y -- member JsonSerializer --package System.Text.Json    # scan members
dnx dotnet-inspect -y -- type --package System.Text.Json                     # scan types
dnx dotnet-inspect -y -- diff --package System.CommandLine@2.0.0-beta4.22272.1..2.0.3  # triage changes

Optional formats: --oneline, --plaintext, --json, --mermaid. Verbosity -v:q/m/n/d controls which sections are included; formatter and verbosity compose freely (--oneline and -v cannot be combined).

Use diff first when fixing broken code — triage changes, then drill into specifics with member.

Key Syntax

Generic types need quotes: 'Option<T>', 'IEnumerable<T>' — use <T> not <> ("Option<>" resolves to the abstract base)
type uses -t for type filtering, member uses -m for member filtering (not --filter)
Dotted syntax for member: -m JsonSerializer.Deserialize or fully qualified
Diff ranges use ..: --package System.Text.Json@9.0.0..10.0.0
Limit output with --head N / --tail N — never pipe through head/tail/Select-Object
Derived types only show their own members — query the base type too

Installation

Use dnx (like npx). Always use -y and -- to prevent interactive prompts:

dnx dotnet-inspect -y -- <command>

Full Reference

Version resolution (cache vs. NuGet), platform diffs and release-notes workflow, structured queries, mermaid diagrams, search scopes, the command table, and all filtering/limiting flags (including aliases): see references/command-reference.md.

Related Skills

dotnet-sdk-builder — Uses this skill to query existing libraries when generating SDK wrappers
dotnet-reviewer — Uses this skill to investigate API surface and version diffs during reviews
dotnet-nuget-manager — Use this skill to inspect package APIs before upgrading or replacing them

The full skill overview lives in the dotnet router skill.

dotnet-inspect

dotnet-inspect

When to Use / Decision Tree