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Cadenza

Write C# like a script. Ship it like Go. No orchestra. No project. Just one file, playing solo.

Cadenza is a family of MSBuild SDKs that turn .NET 10+ file-based apps into a real workflow. Pick the SDK that matches the shape of your program with a single #:sdk directive — the file stays one file.

#!/usr/bin/env dotnet run
#:sdk Cadenza.Web@1.0.15

Get("/", () => "Hello from Cadenza.Web");
await Run();

Run it: dotnet run app.cs. Ship it: dotnet publish app.cs for a self-contained single binary, or /t:PublishContainer for an OCI image — without a Dockerfile.

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Start here

• Getting Started — first script in three minutes
• Installation — what you need on the machine, plus dotnet new cadenza templates
• Editor Setup — full IntelliSense in VS Code / Cursor / Kiro / Rider

Pick an SDK

SDK	What it is
Cadenza Console	CLI tools, shell automation, one-shot scripts
Cadenza Worker	Background services, daemons, long-running loops
Cadenza Web	Minimal APIs, HTTP services
Cadenza Mcp	MCP (Model Context Protocol) servers
Cadenza Agent	Local AI agents — OpenAI Chat Completions + Responses API

Reference

• Tier 1 API — bare names available without imports (Glob, Get, Tool, Log, Run, …)
• Directives — #:sdk, #:package, #:include, #:property
• Samples — annotated tour of every .cs in samples/

Ship

• Deployment Single Binary — dotnet publish flow, JIT vs AOT, trimming
• Deployment Container — /t:PublishContainer, no Dockerfile

When things break

• Troubleshooting — #:sdk resolution errors, stale NuGet cache, MCP stdio framing, container binding, …
• FAQ

Around it

• Source on GitHub
• Packages on NuGet
• Full spec (spec.md) — authoritative reference

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Cadenza targets .NET 10+. Current line: 1.0.x. Licensed MIT.