---
title: "Type Design for Performance - Air Market"
description: "You are writing .NET types and the choices you make now, class or struct, sealed or not, which collection, are hard to undo later. This gives you the decisions worth making deliberately. Reach for it…"
canonical: "https://airmarket.ai/app/type-design-performance"
---

[Air Market](/) / [Developer Tools](/category/devtools) / Type Design for Performance

Skill by [Aaron Stannard](/@aaronontheweb)

# Type Design for Performance

Shape your .NET types with performance in mind from the start

## What this does

You are writing .NET types and the choices you make now, class or struct, sealed or not, which collection, are hard to undo later. This gives you the decisions worth making deliberately. Reach for it when you are designing types and would rather not find the cost after the code is everywhere.

### Top 3 things it does for you

- Design .NET types for performance
- Pick the right collection type
- Decide what to seal and what to make readonly

## Information

**Type Design for Performance at a glance**

|  |  |
| --- | --- |
| Kind | Skill |
| Publisher | [Aaron Stannard](/@aaronontheweb) |
| Category | [Developer Tools](/category/devtools) |
| Works with | Agent Skills - an open standard supported by 40+ agents |
| Size | 10 KB |
| Licence | MIT |
| Repository | [Aaronontheweb/dotnet-skills](https://github.com/Aaronontheweb/dotnet-skills/tree/316756fb309b9ee42d86d5db0d70504d62f3b0c3/skills/csharp-type-design-performance) |
| GitHub stars | 1,123 (as of Nov 2026) |

## Security report

**Verified.** AIR scanned this exact version of Type Design for Performance and flagged nothing. AIR's verdict: **safe**.

**What Type Design for Performance's check was run against**

|  |  |
| --- | --- |
| Commit | 316756fb309b9ee42d86d5db0d70504d62f3b0c3 |
| Content hash | 3a3e9621e9869107a8f87fb28cbe66774afc5d6970df0a5449f4af54c7f91d86 |
| Files read | [Browse the files at this exact commit](https://github.com/Aaronontheweb/dotnet-skills/blob/316756fb309b9ee42d86d5db0d70504d62f3b0c3/skills/csharp-type-design-performance/SKILL.md) |

A scan is named by the exact content it read, not by a version number. A different version is a different artifact, and nothing here applies to a version AIR has not scanned.

[Read the full security report for Type Design for Performance](/security/type-design-performance)

## About Type Design for Performance

Guidance for designing .NET types with performance in mind: sealing classes, using readonly structs, preferring static pure functions, avoiding premature enumeration, and choosing the right collection types.

## What's inside

- SKILL.md - instructions

## Questions

### Is Type Design for Performance safe to install?

AIR scanned this exact version of Type Design for Performance and flagged nothing. AIR's verdict: safe. The verdict is named by the content that was read, at commit 316756fb309b, so it cannot drift onto a version nobody scanned. The full report is at https://airmarket.ai/security/type-design-performance.

### How do I install Type Design for Performance?

Open https://airmarket.ai/app/type-design-performance on Air Market and use the install action: Air Market hands Claude a prompt naming this exact skill, and Claude sets it up. Source, pinned to the exact commit this listing describes: https://github.com/Aaronontheweb/dotnet-skills/tree/316756fb309b9ee42d86d5db0d70504d62f3b0c3/skills/csharp-type-design-performance. Install from that link, not the branch.

## Related on Air Market

- [More Developer Tools listings](/category/devtools)
- [Everything by Aaron Stannard](/@aaronontheweb)

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Canonical URL: <https://airmarket.ai/app/type-design-performance>