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

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