A workflow guide for C# and .NET work. It examines the project and directs coding tasks through the appropriate checks and supporting skills.

Implementing, debugging, reviewing, refactoring, or modernizing C# and .NET code, including running tests, analyzers, formatting, and coverage checks.

It reduces guesswork about language versions, project rules, tests, and quality checks. It also helps ensure changes are checked using the repository’s own standards.

How managedcode/MCPGateway configures Codex

Reuse

Borrowing it

Nothing to install: this file belongs to managedcode/MCPGateway. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/managedcode/MCPGateway/main/.codex/skills/mcaf-dotnet/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/managedcode/MCPGateway

Made for: 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/managedcode/mcpgateway/mcaf-dotnet/github.svg)](https://agentmods.dev/skills/managedcode/mcpgateway/mcaf-dotnet)

Your own site

<a href="https://agentmods.dev/skills/managedcode/mcpgateway/mcaf-dotnet"><img src="https://agentmods.dev/badge/skills/managedcode/mcpgateway/mcaf-dotnet/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/managedcode/mcpgateway/mcaf-dotnet"><img src="https://agentmods.dev/badge/skills/managedcode/mcpgateway/mcaf-dotnet.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,560 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.

Model	Per session	Once invoked
Fable 5.1	$0.00087	$0.01560
Opus 5.5	$0.00035	$0.00624
Sonnet 5.5	$0.00017	$0.00312
Haiku 4.5	$0.00009	$0.00156

Measured 1mo ago against content hash 28d253a1204f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcaf-dotnet 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 1mo 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 mcaf-dotnet — 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.

.codex/skills/mcaf-dotnet/SKILL.md · 136 lines

How it starts

The opening of the file, as written. The whole thing — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCAF: .NET

Trigger On

writing, reviewing, debugging, or refactoring C# or .NET code
deciding which .NET skill should be used for a task
modernizing a .NET codebase while keeping language and runtime compatibility
verifying .NET changes with analyzers, formatting, tests, and coverage

Value

produce a concrete project delta: code, docs, config, tests, CI, or review artifact
reduce ambiguity through explicit planning, verification, and final validation skills
leave reusable project context so future tasks are faster and safer

Do Not Use For

non-.NET repositories
a single-tool task where one exact .NET tool skill already covers the whole request

Inputs

the nearest AGENTS.md
solution and project files
Directory.Build.* files
the repo-root .editorconfig and any nested .editorconfig files that apply
target TFM, LangVersion, SDK version, test packages, and analyzer packages

Quick Start

Read the nearest AGENTS.md and confirm scope and constraints.
Run this skill's Workflow through the Ralph Loop until outcomes are acceptable.
Return the Required Result Format with concrete artifacts and verification evidence.

Workflow

Detect the real stack before changing code or commands:
- TFM or TFMs
- explicit LangVersion or the default implied by the SDK and target framework
- test framework: xUnit, TUnit, or MSTest
- runner model: VSTest or Microsoft.Testing.Platform
- installed analyzers, formatters, coverage tools, and architecture-test libraries
Route framework mechanics through exactly one matching test skill:
- mcaf-dotnet-xunit
- mcaf-dotnet-tunit
- mcaf-dotnet-mstest
Route quality and policy through the matching skill:
- mcaf-dotnet-quality-ci
- mcaf-dotnet-analyzer-config
- mcaf-dotnet-complexity
- tool-specific skills such as mcaf-dotnet-format, mcaf-dotnet-roslynator, mcaf-dotnet-stylecop-analyzers, mcaf-dotnet-meziantou-analyzer, mcaf-dotnet-coverlet, mcaf-dotnet-reportgenerator, mcaf-dotnet-resharper-clt, mcaf-dotnet-netarchtest, mcaf-dotnet-archunitnet, mcaf-dotnet-codeql, mcaf-dotnet-csharpier, and mcaf-dotnet-stryker
Route design and structure through:
- mcaf-solid-maintainability for SOLID, SRP, cohesion, and maintainability limits
- mcaf-architecture-overview when system or module boundaries, contracts, or architecture docs need work
- mcaf-dotnet-features when modern C# feature selection or language-version compatibility matters
Write or review code using the newest stable C# features the repo actually supports.
After any .NET code change, run the repo-defined post-change quality pass from narrow to broad:
- format
- build
- analyze
- focused test
- broader test
- coverage and report generation when configured
- extra configured gates such as Roslynator, StyleCop, Meziantou, ReSharper CLT, NetArchTest, ArchUnitNET, CodeQL, CSharpier, or Stryker
If the repo does not define these commands clearly, tighten AGENTS.md before continuing so later agents stop guessing.
Do not introduce preview language features unless the repo explicitly opts into preview in project or MSBuild settings.

Read the full file on GitHub · 136 lines

Files

What ships with it

2 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.

1mo ago First seen · 136 lines · 87 tokens per session scan A 28d253a1204f

Subscribe to this mod's changes

mcaf-dotnet is a skill published in the GitHub repository managedcode/MCPGateway (5 stars, last pushed 8d ago), licensed MIT. It adds 87 tokens to every session and 1,560 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to mcaf-dotnet, differing in 0 lines, and is treated as a copy.

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Generate the code from typespec for C#. Parameter: C# SDK repository root location .

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MCPGateway: Skill for Codex