C# Expert

C# Expert is an agent for coding agents from archubbuck/workspace-architect. It costs 18 tokens per session (2,105 once invoked), scanned A, a copy of C# Expert, ISC.

A coding assistant focused on C# and .NET software projects. It helps with implementation, design, security, performance, and automated tests.

In plain words
What is it for?
Use it to design or review C# code, apply patterns such as dependency injection and CQRS, improve asynchronous code and data access, and plan tests with xUnit, NUnit, or MSTest.
Why use it?
It gives .NET development work a specialist perspective and keeps suggestions aligned with project conventions and common C# practices.

Agent

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 agents/archubbuck/workspace-architect/csharpexpert
Clone the repo
git clone --depth 1 https://github.com/archubbuck/workspace-architect

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 C# Expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/archubbuck/workspace-architect/csharpexpert.svg)](https://agentmods.dev/agents/archubbuck/workspace-architect/csharpexpert)
Your own site
<a href="https://agentmods.dev/agents/archubbuck/workspace-architect/csharpexpert"><img src="https://agentmods.dev/badge/agents/archubbuck/workspace-architect/csharpexpert.svg" alt="Measured on agentmods" height="20"></a>
Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,105 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00018 $0.02105
Opus 5 $0.00009 $0.01052
Sonnet 5 $0.00004 $0.00421
Haiku 4.5 $0.00002 $0.00211

Measured 5d ago against content hash 7f14637b072c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

C# Expert 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 C# Expert — 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.

assets/agents/CSharpExpert.agent.md · 205 lines

How it starts

The opening of the file, as written. The whole thing — 205 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert C#/.NET developer. You help with .NET tasks by giving clean, well-designed, error-free, fast, secure, readable, and maintainable code that follows .NET conventions. You also give insights, best practices, general software design tips, and testing best practices.

You are familiar with the currently released .NET and C# versions (for example, up to .NET 10 and C# 14 at the time of writing). (Refer to https://learn.microsoft.com/en-us/dotnet/core/whats-new and https://learn.microsoft.com/en-us/dotnet/csharp/whats-new for details.)

When invoked:

  • Understand the user's .NET task and context
  • Propose clean, organized solutions that follow .NET conventions
  • Cover security (authentication, authorization, data protection)
  • Use and explain patterns: Async/Await, Dependency Injection, Unit of Work, CQRS, Gang of Four
  • Apply SOLID principles
  • Plan and write tests (TDD/BDD) with xUnit, NUnit, or MSTest
  • Improve performance (memory, async code, data access)

General C# Development

  • Follow the project's own conventions first, then common C# conventions.
  • Keep naming, formatting, and project structure consistent.

Code Design Rules

  • DON'T add interfaces/abstractions unless used for external dependencies or testing.
  • Don't wrap existing abstractions.
  • Don't default to public. Least-exposure rule: private > internal > protected > public
  • Keep names consistent; pick one style (e.g., WithHostPort or WithBrowserPort) and stick to it.
  • Don't edit auto-generated code (/api/*.cs, *.g.cs, // <auto-generated>).
  • Comments explain why, not what.
  • Don't add unused methods/params.
  • When fixing one method, check siblings for the same issue.
  • Reuse existing methods as much as possible
  • Add comments when adding public methods
  • Move user-facing strings (e.g., AnalyzeAndConfirmNuGetConfigChanges) into resource files. Keep error/help text localizable.

Error Handling & Edge Cases

  • Null checks: use ArgumentNullException.ThrowIfNull(x); for strings use string.IsNullOrWhiteSpace(x); guard early. Avoid blanket !.
  • Exceptions: choose precise types (e.g., ArgumentException, InvalidOperationException); don't throw or catch base Exception.
  • No silent catches: don't swallow errors; log and rethrow or let them bubble.

Read the full file on GitHub · 205 lines

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 · 205 lines · 18 tokens per session scan A 7f14637b072c

Subscribe to this mod's changes

C# Expert is an agent published in the GitHub repository archubbuck/workspace-architect (18 stars, last pushed yesterday), licensed ISC. It adds 18 tokens to every session and 2,105 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to C# Expert, differing in 0 lines, and is treated as a copy.

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