dotnet-pinvoke

dotnet-pinvoke is a skill for Claude Code, Codex from managedcode/dotnet-skills. It costs 119 tokens per session (4,715 once invoked), scanned A, a copy of dotnet-pinvoke, MIT.

A guide to calling C and C++ libraries from .NET using declarations that connect managed C# code to native code. It covers data conversion, strings, memory, handles, and cross-platform differences.

In plain words
What is it for?
Use it to create, review, debug, or modernize P/Invoke and LibraryImport wrappers around native libraries.
Why use it?
Incorrect native function declarations can cause crashes, corrupted data, missing-library errors, or memory leaks that are difficult to trace.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to create, review, debug, or modernize P/Invoke and LibraryImport wrappers around native libraries.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/managedcode/dotnet-skills/dotnet-pinvoke
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add managedcode/dotnet-skills --skill dotnet-pinvoke
Clone the repo
git clone --depth 1 https://github.com/managedcode/dotnet-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for dotnet-pinvoke

README.md
[![agentmods](https://agentmods.dev/badge/skills/managedcode/dotnet-skills/dotnet-pinvoke/github.svg)](https://agentmods.dev/skills/managedcode/dotnet-skills/dotnet-pinvoke)
Your own site
<a href="https://agentmods.dev/skills/managedcode/dotnet-skills/dotnet-pinvoke"><img src="https://agentmods.dev/badge/skills/managedcode/dotnet-skills/dotnet-pinvoke/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for dotnet-pinvoke

Your own site · 80×15
<a href="https://agentmods.dev/skills/managedcode/dotnet-skills/dotnet-pinvoke"><img src="https://agentmods.dev/badge/skills/managedcode/dotnet-skills/dotnet-pinvoke.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 119 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,715 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00119 $0.04715
Opus 5 $0.00060 $0.02357
Sonnet 5 $0.00024 $0.00943
Haiku 4.5 $0.00012 $0.00471

Measured 5d ago against content hash 40dd8410a9eb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

dotnet-pinvoke scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to dotnet-pinvoke — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

catalog/Platform/Official-DotNet-Advanced/skills/dotnet-pinvoke/SKILL.md · 450 lines

How it starts

The opening of the file, as written. The whole thing — 450 lines — stays where its author put it; the contents beside it link to each section on GitHub.

.NET P/Invoke

Calling native code from .NET is powerful but unforgiving. Incorrect signatures, garbled strings, and leaked or freed memory are the most common sources of bugs — all can manifest as intermittent crashes, silent data corruption, or access violations far from the actual defect.

This skill covers both DllImport (available since .NET Framework 1.0) and LibraryImport (source-generated, .NET 7+). When targeting .NET Framework, always use DllImport. When targeting .NET 7+, prefer LibraryImport for new code. When native AOT is a requirement, LibraryImport is the only option.

When to Use This Skill

  • Writing a new [DllImport] or [LibraryImport] declaration from a C/C++ header
  • Reviewing P/Invoke signatures for correctness (type sizes, calling conventions, string encoding)
  • Wrapping an entire C library for use from .NET
  • Debugging AccessViolationException, DllNotFoundException, or silent data corruption at the native boundary
  • Migrating DllImport declarations to LibraryImport for AOT/trimming compatibility
  • Diagnosing memory leaks or heap corruption involving native handles or buffers

Stop Signals

  • Single function? Map the signature (Steps 1-3), handle strings/memory only if relevant, skip tooling and migration sections.
  • Don't migrate existing DllImport to LibraryImport unless the user asks or AOT/trimming is an explicit requirement.
  • Don't recommend CsWin32 unless the target is specifically Win32 APIs.
  • Don't generate callbacks (Step 8) unless the native API requires function pointers.
  • Review request? Use the validation checklist — don't rewrite working code.

Inputs

Input Required Description
Native header or documentation Yes C/C++ function signatures, struct definitions, calling conventions
Target framework Yes Determines whether to use DllImport or LibraryImport
Target platforms Recommended Affects type sizes (long, size_t) and library naming
Memory ownership contract Yes Who allocates and who frees each buffer or handle

Read the full file on GitHub · 450 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 450 lines · 119 tokens per session scan A 40dd8410a9eb

Subscribe to this mod's changes

dotnet-pinvoke is a skill published in the GitHub repository managedcode/dotnet-skills (477 stars, last pushed 3d ago), licensed MIT. It adds 119 tokens to every session and 4,715 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to dotnet-pinvoke, differing in 0 lines, and is treated as a copy.

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