Docker

What it does

When your agent uses it

• Mentions Docker
• Container health check

Example prompts

• “Docker”
• “Dockerfile”
• “container”
• “/docker”

Requirements

• Docker

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1Multi-stage builds always — Separate build and runtime stages. Build in the SDK image, run in the ASP.NET runtime image.
2. 2Non-root by default — .NET container images support USER app by default since .NET 8. Never run as root in production.
3. 3Layer caching matters — Copy .csproj files and restore before copying source code. This caches NuGet dependencies across builds.
4. 4Health probes at the orchestrator level — Expose a /health/live endpoint and let Kubernetes/Compose probe it. Chiseled and default aspnet…

What it can do on your machine

Read from SKILL.md and the folder at commit 2330089. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are dockerfile, yaml and csharp).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Docker loads about 1.5k tokens when it runs. Until then it costs about 148 tokens; SKILL.md has 299 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~148

When it runs · the whole SKILL.md, loaded when a task matches

~1.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from codewithmukesh/dotnet-claude-kit at commit 2330089, republished under its MIT licence (© codewithmukesh). 299 words, ~1,540 tokens.

name

docker

description

Docker containerization for .NET 10 applications. Covers multi-stage builds, .NET container images, non-root user configuration, health checks, and .dockerignore. Load this skill when containerizing an application with a Dockerfile, optimizing image size, setting up Docker Compose for local development, or when the user mentions "Docker", "Dockerfile", "container", "docker-compose", "image", "multi-stage", "non-root", ".dockerignore", or "container health check". For Dockerfile-less SDK publishing (`dotnet publish /t:PublishContainer`), load the container-publish skill instead.

# Stage 1: Build
FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src

# Copy project files and restore (cached layer)
COPY ["src/MyApp.Api/MyApp.Api.csproj", "src/MyApp.Api/"]
COPY ["src/MyApp.Domain/MyApp.Domain.csproj", "src/MyApp.Domain/"]
COPY ["Directory.Build.props", "."]
COPY ["Directory.Packages.props", "."]
RUN dotnet restore "src/MyApp.Api/MyApp.Api.csproj"

# Copy everything and build
COPY . .
RUN dotnet publish "src/MyApp.Api/MyApp.Api.csproj" \
    -c Release \
    -o /app/publish \
    --no-restore

# Stage 2: Runtime
FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS runtime
WORKDIR /app

# Non-root user (default in .NET 8+ images)
USER app

COPY --from=build /app/publish .

EXPOSE 8080

ENTRYPOINT ["dotnet", "MyApp.Api.dll"]

# docker-compose — probe from outside the app process
services:
  api:
    healthcheck:
      test: ["CMD-SHELL", "wget -qO- http://localhost:8080/health/live || exit 1"]
      interval: 30s
      timeout: 3s
      retries: 3
# Note: CMD-SHELL requires a shell + wget in the image. Use a non-chiseled
# variant for this, or better: let Kubernetes httpGet probes do it —
# they run from the kubelet, needing nothing inside the image.

**/.git
**/.vs
**/bin
**/obj
**/node_modules
**/Dockerfile*
**/docker-compose*
**/tests

services:
  api:
    build:
      context: .
      dockerfile: src/MyApp.Api/Dockerfile
    ports:
      - "5000:8080"
    environment:
      - ASPNETCORE_ENVIRONMENT=Development
      - ConnectionStrings__Default=Host=postgres;Database=myapp;Username=postgres;Password=postgres
      - ConnectionStrings__Redis=redis:6379
    depends_on:
      postgres:
        condition: service_healthy
  # Add postgres/redis services with healthcheck — standard boilerplate

FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src

# Copy solution and all project files
COPY *.slnx .
COPY Directory.Build.props .
COPY Directory.Packages.props .
COPY src/**/*.csproj ./src/

# Restore project structure
RUN for file in src/**/*.csproj; do \
    mkdir -p $(dirname $file) && mv $file $(dirname $file)/; \
    done
RUN dotnet restore

COPY . .
RUN dotnet publish src/MyApp.Api -c Release -o /app/publish --no-restore

// In Program.cs — lightweight health endpoint for Docker
app.MapGet("/health/live", () => Results.Ok("healthy"))
    .ExcludeFromDescription();

# BAD — SDK image is 900MB+, includes compilers
FROM mcr.microsoft.com/dotnet/sdk:10.0
COPY . .
RUN dotnet run

# GOOD — separate build and runtime, runtime image is ~200MB
FROM mcr.microsoft.com/dotnet/aspnet:10.0

# BAD — any source change invalidates the NuGet cache
COPY . .
RUN dotnet restore

# GOOD — copy only project files first, then restore
COPY ["src/MyApp.Api/MyApp.Api.csproj", "src/MyApp.Api/"]
RUN dotnet restore "src/MyApp.Api/MyApp.Api.csproj"
COPY . .

# BAD — running as root (security risk)
FROM mcr.microsoft.com/dotnet/aspnet:10.0
COPY --from=build /app .
ENTRYPOINT ["dotnet", "MyApp.Api.dll"]

# GOOD — use the built-in non-root user
FROM mcr.microsoft.com/dotnet/aspnet:10.0
USER app
COPY --from=build /app .
ENTRYPOINT ["dotnet", "MyApp.Api.dll"]

© codewithmukesh, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in skills/docker of codewithmukesh/dotnet-claude-kit.

Open the folder on GitHubat commit 2330089

Used in 1 other repository

We found 4 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in codewithmukesh/dotnet-claude-kit, which our catalogue first saw on October 7, 2026.

• Resgrid/Core.forge/skills/docker.agents/skills/docker+2 more