dotnet-patterns

dotnet-patterns is a skill for Claude Code, Codex from j4flmao/agent-skills. It costs 90 tokens per session (3,957 once invoked), scanned A, original, MIT.

A guide to common .NET implementation patterns, including CQRS, MediatR pipelines, validation, database access with EF Core, and event sourcing. Event sourcing records changes as events so current state can be rebuilt from them.

In plain words
What is it for?
Use it to create command and query handlers, pipeline behaviors, Result-based error handling, FluentValidation rules, optimized EF Core queries, and event-sourcing components.
Why use it?
It provides repeatable ways to handle requests, validation, errors, database work, and event-based state. This reduces ad hoc code for cross-cutting behavior and data operations.

Skill for Claude CodeCodex

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/j4flmao/agent-skills/patterns
Any agent
npx skills add j4flmao/agent-skills --skill patterns
Clone the repo
git clone --depth 1 https://github.com/j4flmao/agent-skills

Made for: Claude Code, 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.

agentmods badge for dotnet-patterns

README.md
[![agentmods](https://agentmods.dev/badge/skills/j4flmao/agent-skills/patterns.svg)](https://agentmods.dev/skills/j4flmao/agent-skills/patterns)
Your own site
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/patterns"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/patterns.svg" alt="Measured on agentmods" height="20"></a>
Per session 90 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,957 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 $0.00090 $0.03957
Opus 5 $0.00045 $0.01978
Sonnet 5 $0.00018 $0.00791
Haiku 4.5 $0.00009 $0.00396

Measured 4d ago against content hash d6dc2b53348b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dotnet-patterns 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.

skills/backend/dotnet/patterns/SKILL.md · 508 lines

How it starts

The opening of the file, as written. The whole thing — 508 lines — stays where its author put it; the contents beside it link to each section on GitHub.

.NET Patterns

Purpose

Implement production-grade .NET patterns — MediatR pipeline behaviors, CQRS with separate models, Result pattern for explicit error handling, EF Core performance patterns, and event sourcing.

Agent Protocol

Trigger

User request includes: dotnet MediatR pattern, dotnet CQRS, dotnet Result pattern, dotnet EF Core, dotnet pipeline behavior, dotnet FluentValidation, dotnet AutoMapper.

Input Context

  • Architecture (Clean Architecture, Vertical Slices)
  • ORM (EF Core, Dapper)
  • Patterns needed (CQRS, Event Sourcing, Outbox, Saga)
  • Testing approach (xUnit, NUnit)

Output Artifact

Code examples for requested patterns — pipeline behavior, CQRS handler, Result type, EF optimization.

Response Format

Code-first output. Pattern name, problem statement, implementation. No preamble, no postamble.

Completion Criteria

  • MediatR pipeline behaviors ordered
  • CQRS with separate Command/Query handlers
  • Result type with implicit conversions
  • EF Core query optimization applied
  • Unit of Work pattern with SaveChangesAsync

Max Response Length

4096 tokens

Architecture Decision Trees

Pipeline Behavior Order

Order Behavior Purpose
1 LoggingBehavior Log request start/end with timing
2 ValidationBehavior Validate before processing
3 PerformanceBehavior Warn if > threshold (500ms)
4 UnhandledExceptionBehavior Catch and wrap unhandled
5 TransactionBehavior Wrap in DB transaction

Pipeline behaviors run in registration order (first added = outer wrapper, runs first).

FluentValidation vs Data Annotations

Criterion FluentValidation Data Annotations
Separation External to model On model properties
Conditional rules Yes (When/Unless) Limited
Cross-property Yes (Must) No
DI support Yes (inject services) No
Testability Easy (validator per model) Requires model instantiation

Read the full file on GitHub · 508 lines

Files

What ships with it

6 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 · 508 lines · 90 tokens per session scan A d6dc2b53348b

Subscribe to this mod's changes

dotnet-patterns is a skill published in the GitHub repository j4flmao/agent-skills (20 stars, last pushed yesterday), licensed MIT. It adds 90 tokens to every session and 3,957 once invoked, about $0.0005 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 2026-08-30.

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