.NET 10 file-based apps + Claude Code = finally ditching Python for quick utilities

Been a C# developer for 20+ years and always had this friction: when I need a quick utility, the overhead of .csproj/bin/obj feels excessive. So, I'd either accept the bloat or let AI tools default to Python "because it's faster."

.NET 10's file-based apps feature changed this for me.

Now I can just: `dotnet run app.cs`

No project file. No build artifacts. The entire utility can be one file.

But the bigger win was configuring my AI tooling to prefer C# over Python. My reasoning: when AI generates code, I want it in a language I can actually read, review, and maintain. Python isn't hard, but C# is where I'm fluent. I catch issues faster and can extend the code confidently.

My setup:

- Dedicated folder for utility scripts (Documents/Workspace/CSharp/)

- AI skill that triggers on phrases like "create a utility" or hyphenated names like "json-format"

- Rule to check existing utilities first and extend rather than duplicate

- Simple PowerShell function to invoke any script easily

Example utility (hello-world.cs):

```csharp

var name = args.Length > 0 ? string.Join(" ", args) : "World";

Console.WriteLine($"Hello, {name}!");

```

NuGet works too with `#:package Newtonsoft.Json@13.*` directives.

Andrew Lock has a great deep dive if you want the full details: https://andrewlock.net/exploring-dotnet-10-preview-features-1-exploring-the-dotnet-run-app.cs/

Anyone else doing something similar? Curious how others handle quick tooling without project overhead.