# Clr Activation Debugging (agent skill)

> Clr Activation Debugging is an agent skill (a SKILL.md file) from dotnet/skills. Diagnoses .NET Framework CLR activation issues using CLR activation logs (CLRLoad logs) produced by mscoree.dll. It works with Claude Code, Codex, Cursor and GitHub Copilot and has 5,730 GitHub stars across a repository of 4 listed skills.

Diagnoses .NET Framework CLR activation issues using CLR activation logs (CLRLoad logs) produced by mscoree.dll. Use when: the shim picks the wrong runtime, fails to load any runtime, shows unexpected .NET 3.5 Feature-on-Demand (FOD) dialogs, unexpectedly does NOT show FOD dialogs, loads both v2 and v4 into the same process causing failures, or any time someone is wondering "what is happening with .NET Framework activation?" Diagnose .NET Framework runtime activation issues by analyzing CLR…

## Key facts

| Fact | Value |
|---|---|
| Repository | https://github.com/dotnet/skills |
| Skill path | plugins/dotnet-diag/skills/clr-activation-debugging/SKILL.md |
| Skill name | clr-activation-debugging |
| GitHub stars | 5,730 |
| Installs on skills.sh | not listed |
| License | MIT |
| Skills in repo | 4 |
| Plugin marketplace | dotnet-agent-skills |
| Official | yes |
| Works with | Claude Code, Codex, Cursor, GitHub Copilot |
| Category | Testing & QA |
| Last commit | Oct 22, 2026 |

## When it triggers

- Use when: the shim picks the wrong runtime, fails to load any runtime, shows unexpected .
- "what is happening with .NET Framework activation?"

## Add this skill

### Claude Code

```sh
/plugin marketplace add dotnet/skills
/plugin install dotnet-diag@dotnet-agent-skills
```

In the Claude apps, zip the skill folder and upload it under Customize > Skills > + > Upload a skill (code execution must be on).

### ChatGPT / Codex

```sh
git clone --depth 1 https://github.com/dotnet/skills.git
cp -r skills/plugins/dotnet-diag/skills/clr-activation-debugging .agents/skills/clr-activation-debugging   # repo; ~/.agents/skills for all projects
```

### Cursor

```sh
git clone --depth 1 https://github.com/dotnet/skills.git
cp -r skills/plugins/dotnet-diag/skills/clr-activation-debugging .cursor/skills/clr-activation-debugging   # project; ~/.cursor/skills for all projects
```

Sources (checked 2026-10-07): https://code.claude.com/docs/en/skills, https://support.claude.com/en/articles/12512180-using-skills-in-claude, https://learn.chatgpt.com/docs/build-skills, https://cursor.com/docs/context/skills

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Canonical page: https://appsgit.com/skills/dotnet-clr-activation-debugging
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