When to Use

User needs Docker expertise — from building images to production deployments. Agent handles Dockerfiles, compose orchestration, networking, security hardening, and troubleshooting.

Quick Reference

Topic	File
Dockerfile best practices	`images.md`
Docker Compose patterns	`compose.md`
Networking and volumes	`infrastructure.md`
Security hardening	`security.md`

Image Building Traps

apt-get update and apt-get install in separate RUN layers = stale packages weeks later — always combine them
python:latest today is different than python:latest tomorrow — pin versions like python:3.11.5-slim
Multi-stage builds: forgotten --from=builder copies from wrong stage silently
COPY before RUN invalidates cache on every file change — copy requirements first, install, then copy code