Guide · Agent skill
How to use the Docker Expert agent skill
Updated · written with AI from the project's own documentation and checked against our catalogue data
The Docker Expert skill is a set of instructions that tells your AI agent to act as a Docker specialist when you ask about containers, Dockerfiles or Docker Compose files. It is written for people who already know the basics of containers and want better-structured help writing or fixing images, stacks and startup problems. After this guide you will know what the skill changes, how to install it, how to ask for help in a way that triggers it, and what to check before trusting the output.
Docker ExpertRightNow-AI/openfang · Apache-2.0 Download the skill Quick start
- 1Download the ZIP. Download the Docker Expert skill ZIP from this page.
- 2Unzip the skill. Unzip the archive so you have a docker folder containing SKILL.md.
- 3Place it in the skills folder. Move the folder to ~/.claude/skills/ for personal use or to .claude/skills/ inside a project.
- 4Or upload it in the Claude apps. In the Claude apps, go to Settings → Capabilities → Skills and upload the skill.
- 5Ask a Docker question. Describe your Dockerfile, Compose file or container problem in plain language and include the relevant file or logs.
- 6Check the output. Review the agent's suggestions against your environment before running commands or changing production.
What the Docker Expert skill makes the agent do
Once installed, the skill tells the agent to behave as a Docker specialist that helps you build, run, debug and optimize containers, write Dockerfiles, manage Compose stacks and troubleshoot container issues.
The skill gives the agent a checklist of best practices to follow. Examples include pinning specific image tags such as node:20-alpine instead of latest, using multi-stage builds, avoiding root users in production, and ordering Dockerfile instructions so layers cache well.
- Dockerfile guidance: dependencies before source code, a .dockerignore file, COPY --from=builder in multi-stage builds, HEALTHCHECK for production containers, and COPY preferred over ADD.
- Debugging steps: docker logs, docker exec, docker inspect, docker build --no-cache, and docker stats or docker top for resource use.
- Compose guidance: named volumes for persistent data, depends_on with condition: service_healthy, and .env files kept out of version control.
Install the Docker Expert skill
The skill is a single file, SKILL.md, inside a folder named docker. Download the ZIP from this page and unzip it. You can install it in one of two places depending on how you want to use it.
For personal use across projects, unzip the skill into ~/.claude/skills/. For a single project, unzip it into that project's .claude/skills/ folder so it applies only there. In the Claude apps, you can instead upload the skill under Settings → Capabilities → Skills.
- Personal: ~/.claude/skills/
- Project only: .claude/skills/ inside your project
- Claude apps: Settings → Capabilities → Skills
Trigger the skill with natural requests
You do not need a special command. Ask about Docker in plain language and mention the thing you are working on. The skill is about containers, Compose, Dockerfiles and debugging, so requests in those areas are the ones it is meant to shape.
Give the agent the relevant file or error message. Guidance is more useful when the agent can see your actual Dockerfile, Compose file or log output.
- Review this Dockerfile and tell me how to make the image smaller.
- My Compose stack starts but the API cannot reach the database. What should I check?
- This container exits right after starting. Help me find out why.
- Rewrite my Dockerfile to use multi-stage builds and a non-root user.
- Is my docker-compose.yml using depends_on correctly for a health-checked database?
Example: debugging a container that will not start
A typical debugging session follows the steps in the skill. The agent looks at logs first, then inspects the running container, then checks networking, mounts and environment variables. For build problems it may suggest rebuilding without cache to rule out stale layers.
The commands below are the ones the skill itself names. Run them yourself if the agent cannot execute commands on your machine.
- Check output with docker logs, or docker logs --follow to watch live output.
- Open a shell in a running container with docker exec -it <container> sh.
- Check networking, mounts and environment variables with docker inspect <container>.
- For a stale build, rebuild with docker build --no-cache.
docker logs --follow <container>
docker exec -it <container> sh
docker inspect <container>Safety notes: scripts, network and what the agent can run
The skill contains instructions only. It does not run scripts, has no tools of its own and does not use the network. The risk is in what the agent does with its advice, not in the skill file itself.
Docker or Docker Compose must be installed on your machine if you want the agent to run commands. Review any command the agent proposes before running it, especially ones that change running services. The skill's own advice warns against committing secrets to version control and against storing secrets in image layers, so check that the agent's suggested configuration follows that rule.
- No scripts are included and the skill makes no network calls.
- Docker or Docker Compose needs to be installed if the agent runs commands.
- Read proposed commands before running them, particularly on production systems.
- Do not put secrets in image layers; the skill suggests build secrets (--secret) or runtime environment variables.
Tips for getting reliable results
The advice is general. The agent may not know your environment, your registry, your base images or your production constraints, so give it that context. Changes to production should go through your normal review process.
Ask the agent to explain why it recommends a change. That makes it easier to judge whether the advice fits your setup.
- Paste the full Dockerfile or Compose file, not a summary.
- Include the exact error message and the output of docker logs.
- Name your target environment (local development or production) so the agent can apply the right rules.
- Ask it to point out any assumptions about your setup before you apply changes.
What people use it for
- Reviewing a Dockerfile to reduce image size with multi-stage builds and a smaller base image.
- Finding why a Compose service cannot reach another service and checking depends_on and health checks.
- Working out why a container exits on startup using logs, docker exec and docker inspect.
- Pinning image tags and adding a non-root USER to an existing Dockerfile.
- Setting up named volumes and an .env file pattern for a local development stack.
Frequently asked questions
How do I install the Docker Expert agent skill?
Download the ZIP from this page and unzip it so you have a docker folder containing SKILL.md. Put it in ~/.claude/skills/ for personal use or in a project's .claude/skills/ folder for one project. In the Claude apps, you can upload it under Settings → Capabilities → Skills.
What does the Docker Expert skill need to run?
The skill itself is only instructions. Docker or Docker Compose must be installed on your machine if you want the agent to run Docker commands. It runs no scripts and uses no network.
Is the Docker Expert skill free?
This page does not state pricing or licence terms beyond the item's listed licence, which is Apache-2.0. Check the source repository for the licence text before reuse.
Is the Docker Expert skill safe to use on production containers?
The skill contains only guidance and no scripts. Its advice is general and the agent may not know your environment, so review any change with your normal process before applying it to production.
Does this skill work for someone who has never used Docker?
Not really. The skill assumes some familiarity with containers. If you are new to Docker, learn the basics first and then use the skill to review and debug your work.
How is this different from just asking an AI agent about Docker?
The skill gives the agent a fixed set of best practices and debugging steps to follow, such as pinning tags, using multi-stage builds and checking logs before rebuilding. Without it, the agent answers from general knowledge each time.
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Our verdict
Use the Docker Expert skill if you write or fix Dockerfiles and Compose files, or need a consistent checklist for debugging containers that crash, fail health checks or cannot reach each other. Skip it if you need a full Docker introduction or if you plan to make production changes without review, because the advice is general and needs checking against your own setup.
Download the skill