Mend Renovate Now Supports C# File-Based Apps and Cake.Sdk

Mend Renovate automates dependency updates by opening pull requests when newer versions of your dependencies are available. Until recently, if you used .NET single-file scripts or Cake.Sdk build scripts written in C# (e.g. cake.cs or build.cs), Renovate did not look inside those files. Two merged changes fix that: the NuGet manager now understands #:sdk and #:package directives in C# files, and the Cake manager can extract and update packages from InstallTool and InstallTools calls. In this post I'll summarize what was added and how to enable it in your repo.

What Changed

.NET 10 introduced file-based execution for single-file C# apps. In that model, dependencies are declared with #:sdk and #:package at the top of the file instead of in a .csproj. Cake.Sdk uses the same mechanism for build scripts, and tools are installed via InstallTool() or InstallTools() rather than the old #tool directive. Renovate's default file patterns only include project and config files (e.g. .csproj, global.json, dotnet-tools.json), so it did not previously scan plain .cs files. That meant dependencies in cake.cs or other single-file C# scripts were never considered for updates.

Two pull requests extend Renovate to support these formats:

1. feat(manager/nuget): Support single file package directives (merged in v43.26.0)
   The NuGet manager can now extract and update dependencies from C# files that use #:sdk and #:package. Because the target files are regular source files, they are not part of the default managerFilePatterns. You must add the patterns you want (e.g. /\\.cs$/ or something narrower) in your Renovate config.

2. feat(manager/cake): Support extracting nuget packages from InstallTools helper methods (merged in v43.41.0)
   The Cake manager gains support for single-file Cake.Sdk build scripts. It can extract NuGet package references from InstallTool() and InstallTools() method parameters (e.g. InstallTool("dotnet:https://api.nuget.org/v3/index.json?package=DPI&version=2025.12.17.349");). By default the Cake manager still only matches *.cake files, so to have Renovate process C# Cake scripts you need to extend the Cake manager's file patterns in config.

So in practice: use the NuGet manager for #:sdk and #:package in any C# file, and use the Cake manager for Cake-specific constructs (including InstallTool(s)) in C# files. For a typical cake.cs you will often enable both and let each manager handle the directives it understands.

What Renovate Can Update

In a C# single-file script or Cake.Sdk build file, Renovate can now update:

• #:sdk – e.g. #:sdk Cake.Sdk@6.0.0
• #:package – e.g. #:package Cake.Core@6.0.0
• InstallTool() / InstallTools() – e.g. InstallTool("dotnet:https://api.nuget.org/v3/index.json?package=DPI&version=2025.12.17.349");

The #:sdk and #:package directives are handled by the NuGet manager. The Cake manager handles the Cake-specific tool installation methods. Both managers need to be told to look at .cs files (or the specific paths you use) via configuration.

Enabling It in Your Repository

Renovate reads config from your repo (e.g. renovate.json or renovate.json5) and merges it with default and inherited config. To have Renovate consider your C# single-file scripts and Cake.Sdk build files, add the corresponding managerFilePatterns (or the fileMatch-style option your preset uses) so that the NuGet and Cake managers include those files.

Example addition to your Renovate config (e.g. in renovate.json):

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "nuget": {
    "managerFilePatterns": ["/\\.cs$/"]
  },
  "cake": {
    "managerFilePatterns": ["/\\.cs$/"]
  }
}

If you only want to include specific script names (e.g. only cake.cs and build.cs), you can narrow the pattern:

{
  "nuget": {
    "managerFilePatterns": ["/(^|/)(cake|build)\\.cs$/"]
  },
  "cake": {
    "managerFilePatterns": ["/(^|/)(cake|build)\\.cs$/"]
  }
}

After this, Renovate will detect dependencies in those C# files and open PRs when updates are available. You can combine this with your existing presets (e.g. config:recommended) and other options like packageRules or scheduling as needed.

Example Repositories and PRs

Real-world examples of Renovate running against Cake.Sdk-style repos:

• devlead/Devlead.Console – PR #239 shows Renovate updating dependencies in a C# build script.
• azurevoodoo/renovate-cake-sdk-test – A small test repo used to validate the feature; e.g. PR #4, PR #8, PR #9.

Running Renovate locally against that test repo with a config that includes (^|/)(cake|build)\\.cs$ for the Cake manager produces PRs for outdated packages in those files without issues.

Summary

If you use C# single-file apps or Cake.Sdk build scripts with #:sdk, #:package, and InstallTool(s), you can now keep those dependencies up to date with Mend Renovate. Add the appropriate managerFilePatterns for the NuGet and Cake managers so they scan your .cs files (or the specific paths you use), and Renovate will open pull requests for available updates. For more on the managers and config, see the NuGet manager docs, the Cake manager docs, and the Renovate configuration overview.