dotnet-inspect

CLI tool for inspecting .NET libraries and NuGet packages. It is for .NET what docker inspect and kubectl describe are for container land: view package metadata, API surfaces, dependencies, source provenance, and version-to-version changes.

Install or run

dotnet tool install -g dotnet-inspect
dotnet-inspect <command>

Run without installing:

dnx dotnet-inspect -y -- <command>

What it inspects

Source	Examples	Notes
NuGet packages	package System.Text.Json, type --package Markout	Supports versions, custom sources, nuget.config, TFMs, package layout, dependencies, and vulnerabilities.
Restored projects	project ./src/App --agents-index, project ./src/App --readme Markout	Resolves direct package references from project.assets.json for compact package grounding manifests and version-pinned docs.
Platform libraries	library System.Private.CoreLib, library System.Text.Json --version 10.0.0, diff --platform System.Runtime@9.0.0..10.0.0	Resolves installed SDK/runtime assemblies, including runtime-only implementation assemblies with no NuGet package.
Local assets	library ./bin/MyLib.dll, package ./pkg/MyLib.nupkg	Useful for auditing builds before publishing.

Bare names are routed automatically: platform-looking names (System.*, Microsoft.AspNetCore.*) resolve to installed platform libraries; other names resolve as NuGet packages. In API commands, common CoreLib aliases and simple type names such as string, int, DateTime, and Guid resolve to System.Private.CoreLib. Use explicit commands and --package, --platform, or --library when you need a specific source.

Capability inventory

Capability	Commands	Highlights
Package inventory	package	Metadata, versions, TFMs, file layout, dependency tree, metadata audit, vulnerability data, custom feeds, NuGet config support.
Project grounding	project	Direct dependency AGENTS.md frontmatter indexes and version-resolved package docs from restored projects.
Library audit	library	Assembly identity, public key token, trim/AOT metadata, unsafe/interoperability signals, OpenTelemetry support, symbols/PDBs, SourceLink and determinism audit, references, resources, async method classification.
API discovery	type, member, find	Type search, member tables, docs, overload selection, generics, obsolete-member markers, direct calls and callers, source/decompiled/IL drill-in.
API compatibility	diff	Version ranges, package or platform diffs, breaking/additive/potentially-breaking classification, type filters.
Relationships	depends, extensions, implements	Type hierarchies, package dependencies, library reference graphs, extension methods/properties, implementors and subclasses.
Source mapping	type/library/package -S "Source Files", member -S "Source Locations" / "Original Source"	SourceLink URLs, member file/line locations, source fetching, URL verification, token+IL-offset to source-line resolution.
Performance analysis (experimental)	library/type/member -S "Top Leverage", "Performance Triage", "Call Graph", "Caller Graph"	Whole-assembly call-graph leverage ranking — direct callers, root reach, fanout, depth, loop calls — with opt-in per-node cost signals (alloc, copy, unsafe, reflection, throw/exception, catch/finally) and actionable rewrite-shape detection.
Decompiler (experimental)	member -S @Source (Decompiled Source, Annotated Source, Original Source, IL)	Raises method bodies to C#, interleaves IL and hidden-fact annotations, and degrades honestly with DEC#### fidelity diagnostics rather than emitting plausible-but-wrong source.
Agent-friendly output	global flags	Markdown by default, compact --table, normalized --tsv, --jsonl, --plaintext, --json, Mermaid diagrams, section/field projection, --count, table row limiting, built-in head/tail limiting.

Command inventory

Command	Purpose
package X	Inspect NuGet metadata, versions, dependencies, TFMs, layout, and vulnerabilities.
project [path]	Inspect restored direct package references for grounding indexes and package docs.
library X	Inspect assembly metadata, symbols, SourceLink, references, resources, and async methods.
type X	Discover types or render a single type shape.
member X	Inspect members, docs, overloads, decompiled/lowered C#, SourceLink-backed original source, and IL.
find X	Search for types across packages, frameworks, projects, and local assets.
diff X	Compare API surfaces between versions.
extensions X	Find extension methods and C# extension properties for a type.
implements X	Find concrete implementors or subclasses.
depends X	Walk type, package, or library dependency graphs; emits Mermaid diagrams.
cache	Inspect or clear dotnet-inspect caches.
skill	Print the base LLM skill; routes to focused skills (skill list, skill source, skill performance).

Single-type type X output is tree-shaped by default. Use -v:n or -v:d to grow that tree to overload leaves; use --markdown -v:q when you want the compact Markdown section view instead. When an exact type is not found, type treats the query as a best-effort namespace/type prefix browse within the resolved package, library, or platform scope.

Signals

Signals is an evidence report, not a safety certification. Select it with -S Signals. For libraries, Signals reports metadata/provenance observations and acquires a missing PDB when selected to resolve SourceLink. For packages, Signals reports package metadata/assets, dependencies, signature provenance, and NuGet registry observations. The per-source-file reachability pass (SourceLink Availability, SourceLink Missing Files) is selected explicitly with -S because its cost scales with source-file count. The slow, exhaustive content check (SourceLink Integrity) is opt-in only.

Command	Scope	Signals
library X -S Signals	Metadata + provenance	Library metadata/provenance signals; a missing library PDB is acquired to resolve SourceLink.
library X -S "Signals,SourceLink Availability,SourceLink Missing Files"	Detailed SourceLink reachability	Adds the opt-in per-file HEAD pass and reports embedded-source coverage.
library X -S "SourceLink Integrity"	Content verification (slow, opt-in)	Downloads every tracked source file and compares its hash to the PDB checksum; a mismatch exits non-zero. Never runs in a default flow.
package X -S Signals	Full package signals	Package and dependency signals, including known vulnerabilities, package age, dependency vulnerability/deprecation counts, and dependency age.

Integrations

Integrations is a library section for ecosystem support such as AI, ASP.NET Core, Aspire, Authentication, Configuration, Dependency Injection, Logging, Options, Hosting, Health Checks, HTTP Client, OpenAPI, and OpenTelemetry. It is a usability index, not a raw evidence report: focused integration sections list package-owned actionable types and starter APIs rather than assembly references.

Use package Foo --library to inspect one package DLL, or package Foo --all-libraries when the package contains multiple relevant libraries. In all-library mode, singular sections such as Library Info are rendered per library while aggregate sections such as @Integrations roll up rows across libraries and include library provenance when needed. Row formats (--table, --tsv, --jsonl) require one concrete section, such as Library Info, Integrations, Switches, or a focused integration section; use Markdown for category selectors such as @Integrations.

Switches is a peer library section for feature, compatibility, and runtime configuration switches such as FeatureSwitchDefinitionAttribute and AppContext switch names.

Experimental features

These features are under active development. Their output shapes, section names, and signal sets may change between releases.

Performance analysis

The whole-assembly call-graph analyzer ranks the members worth optimizing or hardening first. Select Top Leverage to rank members by direct callers, Root Reach (distinct entry points that transitively reach a member), fanout, depth, and loop calls; Performance Triage surfaces the highest-value allocation pay-dirt first — ranking in-loop (hot) and high-confidence opportunities ahead of raw leverage — across actionable rewrite shapes (small non-escaping arrays, temporary or span-to-array copies, capturing and instance method-group delegates, and value-type boxing) plus allocation-hotspot rows for methods that allocate heavily without matching a specific shape. Use --top, --loop, --min-confidence, and --triage-shape to ask the tool for the curated pay-dirt rows directly instead of post-processing. --top limits the ranked data before rendering; -n N --rows remains a renderer cap and is applied afterward if both are supplied. Drill candidates with Call Graph (bounded outbound tree) and Caller Graph (bounded reverse tree to entry points), and project per-node cost with --fields. Ranking rows carry a copyable Stable selector, Visibility, and Selector; add --all to drill non-public members.

dotnet-inspect library MyLib.dll -S "Top Leverage"
dotnet-inspect type MyType --library MyLib.dll --all -S "Top Leverage"
dotnet-inspect library MyLib.dll -S "Performance Triage"
dotnet-inspect library MyLib.dll --loop --min-confidence high --top 20 --tsv
dotnet-inspect library MyLib.dll --triage-shape capturing-delegate --top 10 --jsonl
dotnet-inspect member MyType Method:1 --library MyLib.dll -S "Call Graph,Facts"
dotnet-inspect member MyType Method:1 --library MyLib.dll -S "Caller Graph" --fields "Throw,Catch,Finally"

Common --triage-shape values include capturing-delegate, box-value-type, small-array, linq-scan-in-loop, string-build-in-loop, enumerator-allocation, and allocation-hotspot.

Decompiler

member -S @Source raises a method body to C# and shows the supporting evidence: Decompiled Source (raised C#), Annotated Source (C# with hidden-fact comments and interleaved IL), Original Source (SourceLink-backed), and IL. The decompiler is exception-safe by construction and degrades honestly: IL with no faithful C# spelling renders as a visible comment and lowers the result's fidelity level (Full → Partial → StructuredOnly → IlOnly → Failed) instead of emitting plausible-but-wrong source, with a stable DEC#### diagnostic on every degradation. If output looks wrong, capture all four sections; maintainers diagnose pipeline state with DecompilerHarness.

dotnet-inspect member JsonSerializer --package System.Text.Json Serialize:1 -S @Source
dotnet-inspect member MyType Method:1 --library MyLib.dll -S "Decompiled Source"
dotnet-inspect member MyType Method:1 --library MyLib.dll -S "Annotated Source"
dotnet-inspect library MyLib.dll --il-offset 0x06000001+0x5

Output and querying

Default output is Markdown. Use Markdown for evidence and narrative, --table for compact human scanning, --tsv for normalized tab-separated rows for agents and scripts, --jsonl for one JSON object per table row, and --json for structured object graphs. Use --plaintext for plain text, --bare for one undecorated payload without changing the selected shape, --rows -n N to cap rendered table rows, --count to reduce a selected section/vector to a single row count, and --mermaid on depends for diagrams. Verbosity is -v:q, -v:m, -v:n, or -v:d. Markdown and JSON can represent multi-section documents; --table, --tsv, and --jsonl render one table/section at a time, so pair them with a specific -S selection when querying sectioned output.

Sections and fields are queryable without a template language:

dotnet-inspect library System.Net.Security -S "Async*"
dotnet-inspect member JsonSerializer --package System.Text.Json -D
dotnet-inspect member JsonSerializer --package System.Text.Json -D --schema
dotnet-inspect type --package System.Text.Json --columns Kind,Name
dotnet-inspect library System.Text.Json -S Symbols --fields "PDB*;SourceLink"
dotnet-inspect library System.Text.Json -S @Audit
dotnet-inspect library System.Text.Json -S "Async*" --count
dotnet-inspect package Microsoft.Extensions.Logging.Abstractions --library -S Integrations
dotnet-inspect library Microsoft.Extensions.Logging.Abstractions -S Integrations
dotnet-inspect library Microsoft.Extensions.Logging.Abstractions -S Logging
dotnet-inspect library System.Diagnostics.DiagnosticSource -S OpenTelemetry
dotnet-inspect library System.Text.Json -S Signals
dotnet-inspect package System.Text.Json --path @readme --content --frontmatter
dotnet-inspect project ./src/App --agents-index --jsonl
dotnet-inspect project ./src/App --readme Markout

For target-based queries, -D reports the effective schema by default: only sections and columns that can actually render for that query. Add --schema for the static schema. Bare -S renders @Default, a curated high-density view; type/member summaries use Method Groups, while member Type -m Name uses Methods overload rows. Lists for -S, --columns, and --fields accept commas or semicolons. Use -S @All to select all sections; it renders the default section first, then remaining sections alphabetically. Workflow categories such as @Source and @Audit expand to scenario-focused section groups.

Common examples

dotnet-inspect library System.Text.Json -S Signals
dotnet-inspect package Microsoft.Extensions.Logging.Abstractions --library -S Integrations
dotnet-inspect library Microsoft.Extensions.Logging.Abstractions -S Integrations
dotnet-inspect library System.Diagnostics.DiagnosticSource -S OpenTelemetry
dotnet-inspect library System.Text.Json -S "Signals,SourceLink Availability,SourceLink Missing Files"
dotnet-inspect library System.Text.Json -S "SourceLink Integrity"
dotnet-inspect package System.Text.Json -S Signals
dotnet-inspect package System.Text.Json --versions
dotnet-inspect project ./src/App --agents-index
dotnet-inspect project ./src/App --readme Markout
dotnet-inspect type string --shape
dotnet-inspect type --package System.Text.Json --table
dotnet-inspect member JsonSerializer --package System.Text.Json -m Serialize
dotnet-inspect member JsonSerializer --package System.Text.Json -m Serialize -S "Member Index"
dotnet-inspect member JsonSerializer --package System.Text.Json -m Serialize -S "Source Locations"
dotnet-inspect member JsonSerializer --package System.Text.Json Serialize:1 -S @Source
dotnet-inspect member JsonSerializer --package System.Text.Json Serialize:1 -S Calls
dotnet-inspect member JsonSerializer --package System.Text.Json Serialize:1 -S Callers
dotnet-inspect member string IndexOf:7 -S Callers --caller-package System.Text.Json@9.0.0 --tfm net9.0
dotnet-inspect member MyApi.Helper Run:1 --library MyLib.dll --bin ./app/bin/Release/net10.0
dotnet-inspect member JsonSerializer --package System.Text.Json Serialize:1 -S "Call Graph"
dotnet-inspect member MyType MyMethod:1 --library MyLib.dll -S "Unsafe*"
dotnet-inspect library System.Text.Json --il-offset 0x06000004+0x15
dotnet-inspect diff --package System.Text.Json@9.0.0..10.0.0 --breaking
dotnet-inspect depends Stream --markdown --mermaid

Requirements

.NET 10.0 SDK or later.

LLM integration

dotnet-inspect is designed for LLM-driven development. The embedded skill (dotnet-inspect skill) is also distributed through the dotnet/skills marketplace.

Contributor and agent docs

Start with docs/overview.md for system context. AGENTS.md is the agent resolver for this repo, and taste/skill-guidance.md captures good and bad examples for maintaining the embedded skill.

License

MIT