dotnet-inspect

Query .NET library APIs — the same commands work across NuGet packages, platform libraries (System., Microsoft.AspNetCore.), and local .dll/.nupkg files.

Quick Decision Tree

• Code broken? → diff --package Foo@old..new first, then member --oneline
• Need API surface? → member Type --package Foo --oneline (token-efficient)
• Need signatures? → member Type --package Foo -m Method (default shows full signatures + docs)
• Need source/IL? → member Type --package Foo -m Method -v:d (adds Source, Lowered C#, IL)
• Need constructors? → member 'Type<T>' --package Foo -m .ctor (use <T> not <>)
• Need all overloads? → member Type --package Foo --select (shows Name:N indices)

When to Use This Skill

• "What types are in this package?" — type discovers types (terse), find searches by pattern
• "What's the API surface?" — type for discovery, member for detailed inspection (docs on)
• "What changed between versions?" — diff classifies breaking/additive changes
• "This code uses an old API — fix it" — diff the old..new version, then member --oneline to see the new API
• "What extends this type?" — extensions finds extension methods/properties
• "What implements this interface?" — implements finds concrete types
• "What does this type depend on?" — depends walks the type hierarchy upward
• "What version/metadata does this have?" — package and library inspect metadata
• "Show me something cool" — demo runs curated showcase queries

Key Patterns

Use --oneline as the default for scanning — it works on type, member, find, diff, and implements:

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

Use --shape to understand a type's hierarchy and surface at a glance:

dnx dotnet-inspect -y -- type 'HashSet<T>' --platform System.Collections --shape

Use diff first when fixing broken code — --oneline for triage, then full detail on specific types:

dnx dotnet-inspect -y -- diff --package System.CommandLine@2.0.0-beta4.22272.1..2.0.3 --oneline  # what changed?
dnx dotnet-inspect -y -- diff -t Command --package System.CommandLine@2.0.0-beta4.22272.1..2.0.3  # detail on Command
dnx dotnet-inspect -y -- member Command --package System.CommandLine@2.0.3 --oneline              # new API surface

Search Scope

Search commands (find, extensions, implements, depends) use scope flags:

• (no flags) — platform frameworks + Microsoft.Extensions.AI
• --platform — all platform frameworks
• --extensions — curated Microsoft.Extensions.* packages
• --aspnetcore — curated Microsoft.AspNetCore.* packages
• --package Foo — specific NuGet package (combinable with scope flags)

type, member, library, diff accept --platform <name> as a string for a specific platform library.

Command Reference

Command	Purpose
type	Discover types — terse output, no docs, use --shape for hierarchy
member	Inspect members — docs on by default, supports dotted syntax (-m Type.Member)
find	Search for types by glob pattern across any scope
diff	Compare API surfaces between versions — breaking/additive classification
extensions	Find extension methods/properties for a type
implements	Find types implementing an interface or extending a base class
depends	Walk the type dependency hierarchy upward (interfaces, base classes)
package	Package metadata, files, versions, dependencies, search for NuGet discovery
library	Library metadata, symbols, references, dependencies
demo	Run curated showcase queries — list, invoke, or feeling-lucky

Output Limiting

Do not pipe output through head, tail, or Select-Object. The tool has built-in line limiting that preserves headers and formatting:

dnx dotnet-inspect -y -- member JsonSerializer --package System.Text.Json --oneline -10  # first 10 lines
dnx dotnet-inspect -y -- find "*Logger*" -n 5                                            # first 5 lines
dnx dotnet-inspect -y -- member JsonSerializer --package System.Text.Json -v:q -s Methods  # select specific section

• -n N or -N — line limit, like head. Keeps headers, truncates cleanly.
• -s Section — show only a specific section (glob-capable). Use -s alone to list available sections.
• -v:q — quiet verbosity for compact summary output.

Key Syntax

• Generic types need quotes: 'Option<T>', 'IEnumerable<T>'
• Use <T> not <> for generic types — "Option<>" resolves to the abstract base, 'Option<T>' resolves to the concrete generic with constructors
• type uses -t for type filtering, member uses -m for member filtering (not --filter)
• Dotted syntax for member: -m JsonSerializer.Deserialize
• Diff ranges use ..: --package System.Text.Json@9.0.0..10.0.0
• Signatures include params and default values from metadata
• Derived types only show their own members — query the base type too (e.g., RootCommand inherits Add() and SetAction() from Command)

Installation

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

dnx dotnet-inspect -y -- <command>

Full Documentation

For comprehensive syntax, edge cases, and the flag compatibility matrix:

dnx dotnet-inspect -y -- llmstxt