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.
npx skills add managedcode/dotnet-skills --skill clr-activation-debugginggit clone --depth 1 https://github.com/managedcode/dotnet-skillsWrote 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.
[](https://agentmods.dev/skills/managedcode/dotnet-skills/clr-activation-debugging)<a href="https://agentmods.dev/skills/managedcode/dotnet-skills/clr-activation-debugging"><img src="https://agentmods.dev/badge/skills/managedcode/dotnet-skills/clr-activation-debugging/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.
<a href="https://agentmods.dev/skills/managedcode/dotnet-skills/clr-activation-debugging"><img src="https://agentmods.dev/badge/skills/managedcode/dotnet-skills/clr-activation-debugging.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00102 | $0.05063 |
| Opus 5 | $0.00051 | $0.02531 |
| Sonnet 5 | $0.00020 | $0.01013 |
| Haiku 4.5 | $0.00010 | $0.00506 |
Grade A, and why
clr-activation-debugging 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 4d 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.
This is a copy
100% identical to clr-activation-debugging — 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.
How it starts
The opening of the file, as written. The whole thing — 297 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLR Activation Debugging
Diagnose .NET Framework runtime activation issues by analyzing CLR activation logs (CLRLoad logs) produced by the shim (mscoree.dll). These logs record every decision the shim makes when selecting and loading a CLR version.
When to Use
- A process fails to load the CLR at all ("Unable to find a version of the runtime to use")
- The shim picks the wrong CLR version (e.g., v2.0 instead of v4.0)
- Unexpected .NET 3.5 Feature-on-Demand (FOD) install dialogs appear
- FOD dialogs are expected but do NOT appear
- Both CLR v2 and CLR v4 load into the same process, causing failures
- A COM object fails to activate because the shim can't resolve the runtime
- Legacy hosting APIs (CorBindToRuntime) bind to an unexpected version
When Not to Use
- Modern .NET (CoreCLR / .NET 5+) — this skill covers .NET Framework only (the mscoree.dll shim)
- Assembly binding failures — use Fusion logs (fuslogvw.exe), not CLR activation logs
- Runtime crashes after the CLR has loaded — activation succeeded; the problem is elsewhere
Background
The Shim Architecture
The .NET Framework shim has two layers:
- mscoree.dll (the "shell shim") — the public-facing DLL that is the registered
InprocServer32for CLR-hosted COM objects and the entry point for_CorExeMain, legacy APIs, etc. - mscoreei.dll — the actual shim implementation where the runtime selection logic, logging, and activation decisions live. mscoree.dll forwards into mscoreei.dll.
When reading logs, the caller-name:mscoreei.dll in FOD command lines reflects this — it's mscoreei.dll doing the work.
.NET 3.5 / v2.0.50727 Version Mapping
.NET 2.0, 3.0, and 3.5 all share the same CLR runtime version: v2.0.50727. The "3.0" and "3.5" releases were library additions on top of CLR v2.0. For activation purposes, they are all "v2.0.50727." When the shim resolves to v2.0.50727 or FOD offers to install "NetFx3", it's installing the CLR v2.0 runtime (plus the 3.0/3.5 libraries). Similarly, CLR v4.0 (v4.0.30319) covers all .NET Framework versions from 4.0 through 4.8.x.
What ships with it
4 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.
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.
- 4d ago Changed · +2 lines de030774c23c
- 5d ago First seen · 295 lines · 102 tokens per session scan A 84db80e2fed9
clr-activation-debugging is a skill published in the GitHub repository managedcode/dotnet-skills (477 stars, last pushed 4d ago), licensed MIT. It adds 102 tokens to every session and 5,063 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to clr-activation-debugging, differing in 0 lines, and is treated as a copy.
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