dotnet-backend-patterns

A set of patterns and guidance for building C# and .NET backends, including web APIs, MCP servers, and enterprise services. It covers structure, data access, caching, errors, resilience, testing, and monitoring.

In plain words
What is it for?
Use it when developing or reviewing .NET APIs or servers, designing service boundaries, configuring dependency injection, working with databases or Redis, and adding tests or observability.
Why use it?
It provides consistent decisions for organizing backend code and handling common production concerns such as slow database access, failures, and dependency management.

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/beel-collab/presets.dev/dotnet-backend-patterns
Any agent
npx skills add beel-collab/presets.dev --skill dotnet-backend-patterns
Clone the repo
git clone --depth 1 https://github.com/beel-collab/presets.dev

Made for: Claude Code, Codex.

Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 366 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 $0.00030 $0.00366
Opus 5 $0.00015 $0.00183
Sonnet 5 $0.00006 $0.00073
Haiku 4.5 $0.00003 $0.00037

Measured 2d ago against content hash 693b4d962405, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dotnet-backend-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 2d 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.

claude/skills/backend/dotnet-backend-patterns/SKILL.md · 47 lines

What it actually says

.NET Backend Development Patterns

Master C#/.NET patterns for building production-grade APIs, MCP servers, and enterprise backends with modern best practices (2024/2025).

Use this skill when

  • Developing new .NET Web APIs or MCP servers
  • Reviewing C# code for quality and performance
  • Designing service architectures with dependency injection
  • Implementing caching strategies with Redis
  • Writing unit and integration tests
  • Optimizing database access with EF Core or Dapper
  • Configuring applications with IOptions pattern
  • Handling errors and implementing resilience patterns

Do not use this skill when

  • The project is not using .NET or C#
  • You only need frontend or client guidance
  • The task is unrelated to backend architecture

Instructions

  • Define architecture boundaries, modules, and layering.
  • Apply DI, async patterns, and resilience strategies.
  • Validate data access performance and caching.
  • Add tests and observability for critical flows.
  • If detailed patterns are required, open resources/implementation-playbook.md.

Resources

  • resources/implementation-playbook.md for detailed .NET patterns and examples.

Limitations

  • Use this skill only when the task clearly matches the scope described above.
  • Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
  • Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
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. 2d ago First seen · 47 lines · 30 tokens per session scan A 693b4d962405

Subscribe to this mod's changes

dotnet-backend-patterns is a skill published in the GitHub repository beel-collab/presets.dev (2 stars, last pushed 3mo ago), licensed MIT. It adds 30 tokens to every session and 366 once invoked, about $0.0002 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.

Related

Other skills, from other repositories

agents-sdk-dotnet-activityhandler-migration

Use when migrating a Microsoft 365 Agents SDK agent that uses ActivityHandler or TeamsActivityHandler to AgentApplication. This is ONLY for DotNet projects that uses Microsoft.Agents. packages. Triggered by Agents SDK bots that subclass ActivityHandler or TeamsActivityHandler that need to be modernized to…

microsoft/Agents · 76 tokens

agents-sdk-dotnet

Use when any code imports Microsoft.Agents.Hosting.AspNetCore, Microsoft.Agents.Builder, or related Agents SDK packages, or when the user is building, configuring, or asking questions about a Microsoft 365 Agents SDK agent in C# / .NET. Trigger on questions about appsettings.json, connection configuration…

microsoft/Agents · 112 tokens

agents-sdk-dotnet-otel

Use when adding, configuring, validating, or troubleshooting OpenTelemetry observability for a Microsoft 365 Agents SDK application in C# / .NET. Trigger when the user mentions OpenTelemetry, OTel, telemetry, traces, metrics, logs, OTLP, Aspire Dashboard, Application Insights, Azure Monitor, distributed tracing…

microsoft/Agents · 86 tokens

bf-to-agents-sdk-dotnet-migration

Use when migrating a Bot Framework .NET SDK bot to Microsoft 365 Agents SDK. Triggered by projects that depend on packages: Microsoft.Bot.Builder or Microsoft.Bot.Builder.Integration.AspNet.Core that want to migrate to Agents SDK.

microsoft/Agents · 56 tokens

agents-sdk-dotnet-debugging

Use when troubleshooting an agent built with the Microsoft Agents SDK (Microsoft.Agents.Hosting.AspNetCore and related packages) in C# / .NET. Trigger on any of these symptoms: build or C# compile errors, crashes on startup, 401 or auth errors on incoming requests, the bot not responding to messages, appsettings.json…

microsoft/Agents · 136 tokens

swift-development

You MUST activate this skill when working on Swift projects.

sammcj/agentic-coding · 13 tokens