EpubReader: Agent for Claude Code

.github/agents/CSharpExpert.agent.md

CSharp-Expert is an agent for Claude Code from ne0rrmatrix/EpubReader. It costs 19 tokens per session (2,033 once invoked), scanned A, a copy of C# Expert, MIT.

A software-development agent focused on C# and .NET, Microsoft's platform for building applications and services. It helps with implementation, design, security, performance, and tests while following project conventions.

In plain words
What is it for?
Use it for C#/.NET development tasks, code design, authentication and data protection, asynchronous code, dependency injection, database access, and tests.
Why use it?
It gives .NET developers assistance tailored to the language and platform instead of generic programming advice.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md).

This is ne0rrmatrix/EpubReader's own configuration. It tells Claude Code how to work on EpubReader itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything EpubReader configures →

Reuse

Borrowing it

Nothing to install: this file belongs to ne0rrmatrix/EpubReader. 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/ne0rrmatrix/EpubReader/master/.github/agents/CSharpExpert.agent.md
Clone the repo
git clone --depth 1 https://github.com/ne0rrmatrix/EpubReader

Made for: Claude Code.

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 CSharp-Expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/ne0rrmatrix/epubreader/csharpexpert.svg)](https://agentmods.dev/agents/ne0rrmatrix/epubreader/csharpexpert)
Your own site
<a href="https://agentmods.dev/agents/ne0rrmatrix/epubreader/csharpexpert"><img src="https://agentmods.dev/badge/agents/ne0rrmatrix/epubreader/csharpexpert.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,033 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 94% 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 5.1 $0.00019 $0.02033
Opus 5 $0.00010 $0.01017
Sonnet 5 $0.00004 $0.00407
Haiku 4.5 $0.00002 $0.00203

Measured yesterday against content hash bb897cad7b89, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

CSharp-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 yesterday.

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

94% identical to C# Expert — 7 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.

.github/agents/CSharpExpert.agent.md · 202 lines

How it starts

The opening of the file, as written. The whole thing — 202 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.

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 · 202 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. yesterday First seen · 202 lines · 19 tokens per session scan A bb897cad7b89

Subscribe to this mod's changes

CSharp-Expert is an agent published in the GitHub repository ne0rrmatrix/EpubReader (15 stars, last pushed 14d ago), licensed MIT. It adds 19 tokens to every session and 2,033 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to C# Expert, differing in 7 lines, and is treated as a copy.