Docker

Docker Skill

Comprehensive Docker container and image management through native Docker CLI execution. This skill provides 30 tools for managing your containers, images, networks, volumes, and Docker Compose stacks.

When to Use

• Managing Docker containers (run, exec, logs, stop, start, restart)
• Building and managing Docker images (build, pull, push, tag)
• Viewing container status and resource usage
• Managing Docker networks and volumes
• Running Docker Compose stacks
• Cleaning up unused Docker resources

Requirements

• docker must be installed and in PATH
• Docker daemon must be running
• Appropriate permissions to access Docker socket
• For Compose: Docker Compose V2 (included in Docker Desktop)

Tools Provided

Container Lifecycle Tools

run

Create and start a new container.

Parameters:

• image (required): Container image name[:tag]
• name (optional): Container name
• detach (optional): Run in background (true/false)
• ports (optional): Port mappings (e.g., "8080:80" or "8080:80,443:443")
• volumes (optional): Volume mounts (e.g., "/host:/container" or "/data:/app/data,/logs:/app/logs")
• env (optional): Environment variables (e.g., "KEY=value" or "DB_HOST=localhost,DB_PORT=5432")
• network (optional): Network to connect to
• rm (optional): Remove container when it exits (true/false)
• command (optional): Command to run in container

Example:

skill run docker run image=nginx:latest name=web detach=true ports=8080:80
skill run docker run image=postgres:15 name=db detach=true env="POSTGRES_PASSWORD=secret" volumes=/data:/var/lib/postgresql/data
skill run docker run image=alpine command="echo hello world"

exec

Execute a command in a running container.

Parameters:

• container (required): Container name or ID
• command (required): Command to execute
• interactive (optional): Keep STDIN open (true/false)
• tty (optional): Allocate pseudo-TTY (true/false)
• user (optional): Username or UID
• workdir (optional): Working directory inside container

Example:

skill run docker exec container=web command="ls -la /var/log"
skill run docker exec container=db command="psql -U postgres -c 'SELECT 1'"
skill run docker exec container=app user=node workdir=/app command="npm run migrate"

logs

Fetch container logs.

Parameters:

• container (required): Container name or ID
• tail (optional): Number of lines to show from end
• follow (optional): Follow log output (true/false)
• since (optional): Show logs since timestamp (e.g., "2h", "2024-01-01")
• timestamps (optional): Show timestamps (true/false)

Example:

skill run docker logs container=web tail=100
skill run docker logs container=app since=1h timestamps=true
skill run docker logs container=db follow=true

ps

List containers.

Parameters:

• all (optional): Show all containers including stopped (true/false)
• filter (optional): Filter output (e.g., "status=running", "name=web")
• format (optional): Pretty-print using Go template
• quiet (optional): Only display container IDs (true/false)

Example:

skill run docker ps
skill run docker ps all=true
skill run docker ps filter="status=running"
skill run docker ps quiet=true

start

Start one or more stopped containers.

Parameters:

• container (required): Container name(s) or ID(s), comma-separated for multiple
• attach (optional): Attach STDOUT/STDERR (true/false)

Example:

skill run docker start container=web
skill run docker start container="web,db,cache"

stop

Stop one or more running containers.

Parameters:

• container (required): Container name(s) or ID(s), comma-separated for multiple
• time (optional): Seconds to wait before killing (default: 10)

Example:

skill run docker stop container=web
skill run docker stop container="web,db" time=30

rm

Remove one or more containers.

Parameters:

• container (required): Container name(s) or ID(s), comma-separated for multiple
• force (optional): Force removal of running container (true/false)
• volumes (optional): Remove associated anonymous volumes (true/false)

Example:

skill run docker rm container=web
skill run docker rm container="old-web,old-db" force=true volumes=true

restart

Restart one or more containers.

Parameters:

• container (required): Container name(s) or ID(s), comma-separated for multiple
• time (optional): Seconds to wait before killing (default: 10)

Example:

skill run docker restart container=web
skill run docker restart container="web,api" time=5

inspect

Display detailed information about a container or image.

Parameters:

• target (required): Container or image name/ID
• format (optional): Format output using Go template
• type (optional): Type of object (container, image)

Example:

skill run docker inspect target=web
skill run docker inspect target=nginx:latest type=image
skill run docker inspect target=web format="{{.NetworkSettings.IPAddress}}"

Image Management Tools

images

List images.

Parameters:

• all (optional): Show all images including intermediate (true/false)
• filter (optional): Filter output (e.g., "dangling=true", "reference=nginx*")
• format (optional): Pretty-print using Go template
• quiet (optional): Only show image IDs (true/false)

Example:

skill run docker images
skill run docker images filter="dangling=true"
skill run docker images quiet=true

pull

Pull an image from a registry.

Parameters:

• image (required): Image name[:tag]
• platform (optional): Set platform (e.g., "linux/amd64", "linux/arm64")

Example:

skill run docker pull image=nginx:latest
skill run docker pull image=python:3.11-slim platform=linux/amd64

push

Push an image to a registry.

Parameters:

• image (required): Image name[:tag]

Example:

skill run docker push image=myregistry.com/myapp:v1.0

build

Build an image from a Dockerfile.

Parameters:

• context (required): Build context path (e.g., "." or "/path/to/project")
• file (optional): Path to Dockerfile (default: context/Dockerfile)
• tag (optional): Image tag (e.g., "myapp:v1.0")
• build_arg (optional): Build-time variables (e.g., "VERSION=1.0" or "VERSION=1.0,ENV=prod")
• no_cache (optional): Do not use cache (true/false)
• platform (optional): Set target platform (e.g., "linux/amd64")

Example:

skill run docker build context=. tag=myapp:latest
skill run docker build context=/app file=/app/Dockerfile.prod tag=myapp:prod build_arg="VERSION=1.0"
skill run docker build context=. tag=myapp:latest no_cache=true platform=linux/amd64

tag

Create a tag for an image.

Parameters:

• source (required): Source image name[:tag]
• target (required): Target image name[:tag]

Example:

skill run docker tag source=myapp:latest target=myregistry.com/myapp:v1.0
skill run docker tag source=nginx:latest target=nginx:backup

rmi

Remove one or more images.

Parameters:

• image (required): Image name(s) or ID(s), comma-separated for multiple
• force (optional): Force removal (true/false)

Example:

skill run docker rmi image=nginx:old
skill run docker rmi image="nginx:old,postgres:13" force=true

Network Tools

network-ls

List networks.

Parameters:

• filter (optional): Filter output (e.g., "driver=bridge", "name=my-net")
• format (optional): Pretty-print using Go template

Example:

skill run docker network-ls
skill run docker network-ls filter="driver=bridge"

network-create

Create a network.

Parameters:

• name (required): Network name
• driver (optional): Network driver (bridge, overlay, host, none)
• subnet (optional): Subnet in CIDR format (e.g., "172.20.0.0/16")

Example:

skill run docker network-create name=my-network
skill run docker network-create name=my-network driver=bridge subnet=172.20.0.0/16

network-connect

Connect a container to a network.

Parameters:

• network (required): Network name
• container (required): Container name or ID
• ip (optional): IPv4 address

Example:

skill run docker network-connect network=my-network container=web
skill run docker network-connect network=my-network container=web ip=172.20.0.10

network-disconnect

Disconnect a container from a network.

Parameters:

• network (required): Network name
• container (required): Container name or ID
• force (optional): Force disconnection (true/false)

Example:

skill run docker network-disconnect network=my-network container=web

Volume Tools

volume-ls

List volumes.

Parameters:

• filter (optional): Filter output (e.g., "dangling=true", "name=my-vol")
• format (optional): Pretty-print using Go template

Example:

skill run docker volume-ls
skill run docker volume-ls filter="dangling=true"

volume-create

Create a volume.

Parameters:

• name (required): Volume name
• driver (optional): Volume driver (default: local)

Example:

skill run docker volume-create name=my-data
skill run docker volume-create name=my-data driver=local

volume-rm

Remove one or more volumes.

Parameters:

• name (required): Volume name(s), comma-separated for multiple
• force (optional): Force removal (true/false)

Example:

skill run docker volume-rm name=old-data
skill run docker volume-rm name="old-data,temp-data" force=true

volume-inspect

Display detailed information about a volume.

Parameters:

• name (required): Volume name
• format (optional): Format output using Go template

Example:

skill run docker volume-inspect name=my-data
skill run docker volume-inspect name=my-data format="{{.Mountpoint}}"

Docker Compose Tools

compose-up

Create and start containers defined in docker-compose.yml.

Parameters:

• file (optional): Path to compose file (default: docker-compose.yml)
• detach (optional): Run in background (true/false)
• build (optional): Build images before starting (true/false)
• services (optional): Specific services to start, comma-separated

Example:

skill run docker compose-up detach=true
skill run docker compose-up file=docker-compose.prod.yml detach=true build=true
skill run docker compose-up services="web,db"

compose-down

Stop and remove containers, networks created by compose up.

Parameters:

• file (optional): Path to compose file
• volumes (optional): Remove named volumes (true/false)
• remove_orphans (optional): Remove orphan containers (true/false)

Example:

skill run docker compose-down
skill run docker compose-down volumes=true remove_orphans=true

compose-ps

List containers managed by Compose.

Parameters:

• file (optional): Path to compose file
• all (optional): Show all containers including stopped (true/false)

Example:

skill run docker compose-ps
skill run docker compose-ps all=true

compose-logs

View output from containers.

Parameters:

• file (optional): Path to compose file
• service (optional): Specific service to show logs for
• follow (optional): Follow log output (true/false)
• tail (optional): Number of lines to show

Example:

skill run docker compose-logs
skill run docker compose-logs service=web tail=100
skill run docker compose-logs follow=true

System Tools

system-info

Display system-wide information.

Example:

skill run docker system-info

system-prune

Remove unused data (stopped containers, unused networks, dangling images).

Parameters:

• all (optional): Remove all unused images, not just dangling (true/false)
• volumes (optional): Also prune volumes (true/false)
• force (optional): Do not prompt for confirmation (true/false)

Example:

skill run docker system-prune force=true
skill run docker system-prune all=true volumes=true force=true

raw

Execute any docker command directly.

Parameters:

• args (required): Raw docker arguments

Example:

skill run docker raw args="version"
skill run docker raw args="info --format '{{.ServerVersion}}'"
skill run docker raw args="stats --no-stream"

Configuration

This skill uses your existing Docker configuration. No additional configuration is required.

Configure in .skill-engine.toml:

[skills.docker]
source = "./examples/docker-skill"
description = "Docker container and image management"

[skills.docker.instances.default]
# No config needed - uses system Docker

For remote Docker hosts:

export DOCKER_HOST=tcp://192.168.1.100:2376
export DOCKER_TLS_VERIFY=1

Security Model

Allowed Commands

This skill only executes docker commands through the allowlisted command system.

Blocked Operations

The following operations are blocked for security:

• --privileged flag - Grants full host access
• -v /var/run/docker.sock:/var/run/docker.sock - Docker-in-Docker escape vector
• -v /:/host or similar root filesystem mounts
• --pid=host - Host PID namespace access
• --network=host with --privileged

Warning Operations

The following operations will proceed but should be used with caution:

• --network=host - Container shares host network stack
• Volume mounts to sensitive paths (/etc, /var, /root)
• system-prune with --all --volumes - Can delete important data

Best Practices

1. Use named volumes instead of host path mounts when possible
2. Run containers as non-root users (--user)
3. Limit container capabilities (--cap-drop=ALL --cap-add=...)
4. Use read-only root filesystem when possible (--read-only)
5. Set resource limits (--memory, --cpus)

Troubleshooting

Docker daemon not running

# macOS/Linux
sudo systemctl start docker
# or for Docker Desktop, start the application

Permission denied

# Add user to docker group (Linux)
sudo usermod -aG docker $USER
# Then log out and back in

Container networking issues

# Inspect network settings
skill run docker inspect target=container_name format="{{json .NetworkSettings}}"