dotnet-modernization

dotnet-modernization is a skill for Claude Code, Codex from tqnonline/agent-forge. It costs 234 tokens per session (2,561 once invoked), scanned A, original, BSD-3-Clause.

A migration guide for moving applications from older .NET Framework technology to modern .NET 8 or .NET 9. It covers older systems such as ASP.NET, WCF, Entity Framework 6, and Web Forms.

In plain words
What is it for?
Use it to assess a .NET Framework application, choose between gradual and full migration, modernize WCF, EF6, or Web Forms components, and plan Windows-container fallbacks.
Why use it?
It helps break a large legacy upgrade into manageable parts and identifies migration requirements such as test coverage. It also distinguishes migration planning from designing the new application architecture.

Skill for Claude CodeCodex

Part of the msft-arch plugin — 29 skills, 4 commands, 2 agents shipped together

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.

agentmods
npx agentmods add skills/tqnonline/agent-forge/dotnet-modernization
Any agent
npx skills add tqnonline/agent-forge --skill dotnet-modernization
Clone the repo
git clone --depth 1 https://github.com/tqnonline/agent-forge

Made for: Claude Code, Codex.

Or install msft-arch, the plugin that ships this one along with the rest of its 29 skills, 4 commands, 2 agents.

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-modernization

README.md
[![agentmods](https://agentmods.dev/badge/skills/tqnonline/agent-forge/dotnet-modernization.svg)](https://agentmods.dev/skills/tqnonline/agent-forge/dotnet-modernization)
Your own site
<a href="https://agentmods.dev/skills/tqnonline/agent-forge/dotnet-modernization"><img src="https://agentmods.dev/badge/skills/tqnonline/agent-forge/dotnet-modernization.svg" alt="Measured on agentmods" height="20"></a>
Per session 234 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,561 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00234 $0.02561
Opus 5 $0.00117 $0.01281
Sonnet 5 $0.00047 $0.00512
Haiku 4.5 $0.00023 $0.00256

Measured 4d ago against content hash 0fac79bb532e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dotnet-modernization 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.

plugins/msft-arch/skills/dotnet-modernization/SKILL.md · 180 lines

How it starts

The opening of the file, as written. The whole thing — 180 lines — stays where its author put it; the contents beside it link to each section on GitHub.

.NET Modernization Specialist

Version: 1.0 | Role: .NET Framework to .NET 8/9 LTS Migration Architect | Stack: Migration, Strangler Fig, WCF, EF6, Web Forms, Windows Containers

This skill owns the migration path from .NET Framework 4.x to .NET 8/9 LTS. It covers strategy selection (strangler fig vs. big bang), assessment tooling, component-by-component migration patterns (WCF, EF6, Web Forms), containerization fallbacks, and the test-coverage prerequisite. It does NOT redesign the target-state .NET architecture: that belongs to /dotnet-architect. Chain to /dotnet-architect immediately after the migration plan is complete to design the new world.

Use microsoft_docs_search and microsoft_docs_fetch to verify current .NET Upgrade Assistant status, GitHub Copilot modernization agent capabilities, and .NET 9 migration guidance before finalising decisions. Use microsoft_code_sample_search for gRPC and EF Core sample patterns. Read shared standards: standards/references/coding-stack/csharp-standards.md, standards/references/coding-stack/ef-core-checklist.md.

Migration Principles (non-negotiable)

  • Strangler fig over big bang for any non-trivial codebase (greater than 50K LOC). Big bang is reserved for small, well-tested, low-dependency codebases under active development where a feature freeze is acceptable for the migration window.
  • .NET Upgrade Assistant for assessment phase; manual fixes for the long tail. As of VS 2026 / VS 2022 17.14+, the GitHub Copilot modernization agent replaces the legacy Upgrade Assistant; use whichever tooling matches the customer's VS version, and expect 40-60% automated coverage: the remainder requires human judgment.
  • WCF to gRPC for new internal services; HTTP+OpenAPI for external/integration. CoreWCF is a compatibility bridge, not a destination: use it only when binary-compatible client contracts are a hard constraint during a transition window.
  • EF6 to EF Core: migration is not always 1:1: review LINQ queries, lazy loading, transaction scopes. EF Core disables lazy loading by default, eliminates EntitySQL, changes change-tracker semantics, and removes EDMX. Each difference is a potential regression.
  • ASP.NET Web Forms to Blazor Server (closest paradigm match), then MVC, then Razor Pages. Blazor Server preserves the stateful, event-driven component model that Web Forms developers know; choose MVC or Razor Pages only when server-push latency is a concern or the team already has strong MVC investment.
  • Windows Container as last resort when full migration is not viable for the next 12-18 months. Windows Containers on Windows Server Core lift .NET Framework 4.x apps into a container without code changes; they buy time but do not eliminate the migration debt.
  • Test coverage on legacy code first: modernization without tests is rewriting blind. Establish a characterization test suite against the legacy app before touching a single project file. See references/test-coverage-first.md.

Read the full file on GitHub · 180 lines

Files

What ships with it

7 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. 4d ago First seen · 180 lines · 234 tokens per session scan A 0fac79bb532e

Subscribe to this mod's changes

dotnet-modernization is a skill published in the GitHub repository tqnonline/agent-forge (2 stars, last pushed 3mo ago), licensed BSD-3-Clause. It adds 234 tokens to every session and 2,561 once invoked, about $0.0012 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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