dotnet-aspnet-core

A guide for building and reviewing ASP.NET Core applications, the modern .NET framework for web apps, APIs, and request-processing services.

In plain words
What is it for?
Creating or modernizing ASP.NET Core apps, debugging request pipelines, choosing between web app styles, and reviewing security and hosting patterns.
Why use it?
It helps prevent mistakes in hosting, middleware order, authentication, routing, configuration, logging, and deployment.

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/managedcode/prompterone/dotnet-aspnet-core
Any agent
npx skills add managedcode/PrompterOne --skill dotnet-aspnet-core
Clone the repo
git clone --depth 1 https://github.com/managedcode/PrompterOne

Made for: Claude Code, Codex.

Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,632 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 89% 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 $0.00040 $0.01632
Opus 5 $0.00020 $0.00816
Sonnet 5 $0.00008 $0.00326
Haiku 4.5 $0.00004 $0.00163

Measured 2d ago against content hash 3ff1660e4ef6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dotnet-aspnet-core 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.

Origin

This is a copy

89% identical to aspnet-core — 19 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/dotnet-aspnet-core/SKILL.md · 201 lines

How it starts

The opening of the file, as written. The whole thing — 201 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ASP.NET Core

Trigger On

  • working on ASP.NET Core apps, services, or middleware
  • changing auth, routing, configuration, hosting, or deployment behavior
  • deciding between ASP.NET Core sub-stacks such as Blazor, Minimal APIs, or controller APIs
  • debugging request pipeline issues
  • modernizing legacy ASP.NET to ASP.NET Core

Documentation

References

  • patterns.md - Detailed middleware patterns, security patterns, configuration patterns, DI patterns, error handling patterns, and logging patterns
  • anti-patterns.md - Common ASP.NET Core mistakes including HttpClient misuse, async anti-patterns, configuration errors, DI issues, middleware ordering problems, and security vulnerabilities

Workflow

  1. Detect the real hosting shape first:

    • top-level Program.cs structure
    • middleware order and registration
    • auth model (Identity, JWT, OAuth, cookies)
    • endpoint registrations and routing
  2. Follow the correct middleware order:

    ExceptionHandler → HttpsRedirection → Static Files → Routing
    → CORS → Authentication → Authorization → Rate Limiting
    → Response Caching → Custom Middleware → Endpoints
    
  3. Use built-in patterns correctly:

    • Prefer IOptions<T> / IOptionsSnapshot<T> for configuration
    • Use ILogger<T> for structured logging
    • Use IHttpClientFactory for HTTP clients (never new HttpClient())
    • Use IHostedService / BackgroundService for background work

Read the full file on GitHub · 201 lines

Files

What ships with it

3 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. 2d ago First seen · 201 lines · 40 tokens per session scan A 3ff1660e4ef6

Subscribe to this mod's changes

dotnet-aspnet-core is a skill published in the GitHub repository managedcode/PrompterOne (42 stars, last pushed 3mo ago), licensed MIT. It adds 40 tokens to every session and 1,632 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to aspnet-core, differing in 19 lines, and is treated as a copy.

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