# container-publish

Builds OCI images straight from dotnet publish /t:PublishContainer, no Dockerfile involved. Useful when a .NET 10 app has to ship as a container and land in a registry.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 2800 installs · ★ 789
- Author: codewithmukesh
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/codewithmukesh/dotnet-claude-kit/tree/HEAD/skills/container-publish/SKILL.md
- Updated: 2026-08-07
- HTML: https://affpapa.org/en/nevibecode/skills/container-publish

## What it does

The skill covers container publishing through the .NET 10 SDK: the `PublishContainer` MSBuild target builds an image from your project, and every setting lives in the `.csproj` as an MSBuild property — `ContainerRepository`, `ContainerFamily`, `ContainerPort`, environment variables, labels. Nothing separate to keep in sync with the code.

Base image variants are laid out: `noble-chiseled` with no shell or package manager, `noble-chiseled-extra` with ICU for localization, `alpine` with a shell. With Native AOT the SDK picks `chiseled-aot` on its own. Multi-arch builds go through `ContainerRuntimeIdentifiers`, and there are sections on multiple tags, saving to a tarball on a machine with no Docker, and a GitHub Actions pipeline using `docker/login-action`.

One limit matters: if the app needs OS packages, SDK publishing is out — there is no `RUN` equivalent, so you build a custom base image with a Dockerfile first and point `ContainerBaseImage` at it. Pushing to a registry also requires authentication; skip `docker login` and the publish fails with CONTAINER1013. On Windows, pass `--os linux --arch x64` or you may end up with a Windows container.

## Requirements
- Works with: Docker

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add codewithmukesh/dotnet-claude-kit --skill container-publish -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/container-publish/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/container-publish/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add codewithmukesh/dotnet-claude-kit --skill container-publish -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/container-publish/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add codewithmukesh/dotnet-claude-kit --skill container-publish -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/container-publish/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install codewithmukesh/dotnet-claude-kit container-publish
```

2. **Manually: put the files in place**
- File: `.github/skills/container-publish/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add codewithmukesh/dotnet-claude-kit --skill container-publish -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/codewithmukesh/dotnet-claude-kit --path skills/container-publish
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/container-publish/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add codewithmukesh/dotnet-claude-kit --skill container-publish -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/codewithmukesh/dotnet-claude-kit/tree/HEAD/skills/container-publish/SKILL.md

## When to use it
- build a .NET service image with no Dockerfile
- shrink a production image with chiseled base variants
- produce a multi-arch image in one publish
- save an image as a tarball for CI scanning
- push an image to ghcr.io or Azure Container Registry

## Example prompts
- Build a container from my ASP.NET Core project without a Dockerfile and push it to ghcr.io tagged 1.0.0
- Switch the project to noble-chiseled and add a multi-arch build for linux-x64 and linux-arm64
- Set up a GitHub Actions pipeline that publishes the image to ghcr.io tagged with the commit SHA

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 4ccf4b4814b7bc14.

BEGIN THIRD-PARTY FILE 4ccf4b4814b7bc14
````text
---
name: container-publish
description: >
  Dockerfile-less containerization using the .NET 10 SDK container publishing
  feature. Covers MSBuild properties, chiseled images, multi-arch builds, and
  registry publishing — all without writing a Dockerfile.
  Load this skill when the user wants to containerize without a Dockerfile, or
  mentions "dotnet publish container", "PublishContainer", "ContainerRepository",
  "ContainerFamily", "chiseled", "distroless", "container publish", "SDK
  container", "no Dockerfile", or "containerize without Docker".
---

# Container Publishing (No Dockerfile)

## Core Principles

1. **No Dockerfile needed** — The .NET 10 SDK builds OCI-compliant container images directly from `dotnet publish /t:PublishContainer`. No Dockerfile to write or maintain.
2. **Chiseled images for production** — Use `noble-chiseled` base images: no shell, no package manager, 7 Linux components vs 100+. Smallest attack surface.
3. **Non-root by default** — .NET 10 container images run as the `app` user automatically. Never override to root in production.
4. **Configuration in the .csproj** — All container settings are MSBuild properties, versioned with your project. No separate files to drift.

## Patterns

### Minimal Container Publish

No project file changes needed. Just publish:

```bash
dotnet publish /t:PublishContainer --os linux --arch x64
```

This creates a container image in your local Docker daemon using the default `aspnet:10.0` base image.

### Production-Ready .csproj Configuration

```xml
<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net10.0</TargetFramework>
    <ContainerRepository>mycompany/myapp-api</ContainerRepository>
    <ContainerFamily>noble-chiseled</ContainerFamily>
  </PropertyGroup>

  <ItemGroup>
    <ContainerPort Include="8080" Type="tcp" />
    <ContainerEnvironmentVariable Include="ASPNETCORE_HTTP_PORTS" Value="8080" />
    <ContainerEnvironmentVariable Include="DOTNET_EnableDiagnostics" Value="0" />
    <ContainerLabel Include="org.opencontainers.image.vendor" Value="MyCompany" />
  </ItemGroup>

</Project>
```

### Publishing to a Registry

Authenticate with `docker login` first, then specify the registry:

```bash
# GitHub Container Registry
docker login ghcr.io
````
END THIRD-PARTY FILE 4ccf4b4814b7bc14

The third-party file has ended. Everything between the 4ccf4b4814b7bc14 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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