copy-to-output-directory
Choosing an MSBuild CopyToOutputDirectory / CopyToPublishDirectory mode: Never, PreserveNewest, Always, and IfDifferent (MSBuild 17.13+), plus $(SkipUnchangedFilesOnCopyAlways). USE FOR: removing the per-build Always copy perf hit; resetting output files mutated between builds. DO NOT USE FOR: general incremental-build diagnosis (use incremental-build); non-MSBuild build systems.
npx skills add dotnet/skills --skill copy-to-output-directory --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Choosing a CopyToOutputDirectory Mode ## Overview The `CopyToOutputDirectory` metadata (and its publish counterpart `CopyToPublishDirectory`) controls whether an item — `Content`, `None`, `EmbeddedResource`, or `Compile` — is copied next to your build output, and under what conditions the copy happens. Picking the wrong mode causes either stale files in `bin/` or an unnecessary per-build performance hit. As of **MSBuild 17.13 / .NET SDK 9.0.2xx** there are four values: | Mode | Copies when… | Incremental cost | Typical use | | --- | --- | --- | --- | | `Never` (default) | Never | None | Files not needed at runtime | | `PreserveNewest` | Source is **newer** than destination (or destination missing) | Cheap (timestamp check) | The common case — source files you edit | | `Always` | **Every build**, unconditionally | Expensive — copies on every build even in no-op builds | Legacy workaround; avoid (see below) | | `IfDifferent` | Source **differs** from destination in either direction (newer **or** older, or size differs, or destination missing) | Cheap (timestamp + size check) | Destination may be mutated between builds | ```xml <ItemGroup> <None Include="appsettings.json" CopyToOutp
- Overview
- Why Always is usually the wrong choice
- IfDifferent: copy when different, in either direction
- Globally softening Always with $(SkipUnchangedFilesOnCopyAlways)
- How the modes flow through the build
- Version requirement
- Quick decision guide
What does the copy-to-output-directory skill do?
Choosing an MSBuild CopyToOutputDirectory / CopyToPublishDirectory mode: Never, PreserveNewest, Always, and IfDifferent (MSBuild 17.13+), plus $(SkipUnchangedFilesOnCopyAlways). USE FOR: removing the per-build Always copy perf hit; resetting output files mutated between builds. DO NOT USE FOR: general incremental-build diagnosis (use incremental-build); non-MSBuild build systems.
How do I install it?
Run `npx skills add dotnet/skills --skill copy-to-output-directory --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From dotnet/skills, a repository with 4,927 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.