docker-specialist

docker-specialist is a skill for Claude Code from pwdev-solucoes/pwdev-claude-marketplace. It costs 65 tokens per session (793 once invoked), scanned A, original, Apache-2.0.

A guide to building and securing Docker images and running services with containers. Containers package an application with its required files and dependencies so it can run in a consistent environment.

In plain words
What is it for?
Use it to write Dockerfiles, create multi-stage builds, configure Docker Compose, improve build caching, work with registries, and scan images for vulnerabilities.
Why use it?
It helps reduce oversized images, slow rebuilds, unused files, and avoidable security risks. It also encourages running applications with limited privileges instead of as the root user.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the pwdev-devops plugin — 19 skills, 5 commands, 4 agents shipped together

Good fit Use it to write Dockerfiles, create multi-stage builds, configure Docker Compose, improve build caching, work with registries, and scan images for vulnerabilities.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pwdev-solucoes/pwdev-claude-marketplace/docker-specialist
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add pwdev-solucoes/pwdev-claude-marketplace --skill docker-specialist
Clone the repo
git clone --depth 1 https://github.com/pwdev-solucoes/pwdev-claude-marketplace

Made for: Claude Code.

Or install pwdev-devops, the plugin that ships this one along with the rest of its 19 skills, 5 commands, 4 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for docker-specialist

README.md
[![agentmods](https://agentmods.dev/badge/skills/pwdev-solucoes/pwdev-claude-marketplace/docker-specialist/github.svg)](https://agentmods.dev/skills/pwdev-solucoes/pwdev-claude-marketplace/docker-specialist)
Your own site
<a href="https://agentmods.dev/skills/pwdev-solucoes/pwdev-claude-marketplace/docker-specialist"><img src="https://agentmods.dev/badge/skills/pwdev-solucoes/pwdev-claude-marketplace/docker-specialist/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for docker-specialist

Your own site · 80×15
<a href="https://agentmods.dev/skills/pwdev-solucoes/pwdev-claude-marketplace/docker-specialist"><img src="https://agentmods.dev/badge/skills/pwdev-solucoes/pwdev-claude-marketplace/docker-specialist.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 793 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00065 $0.00793
Opus 5 $0.00032 $0.00396
Sonnet 5 $0.00013 $0.00159
Haiku 4.5 $0.00006 $0.00079

Measured 8d ago against content hash 8ca842d94a53, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

docker-specialist scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

HEALTHCHECK CMD curl -f http://localhost:3000/health || exit 1
plugins/pwdev-devops/skills/docker-specialist/SKILL.md · 82 lines

How it starts

The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Docker Specialist

Você reduz imagem, acelera build e fecha brecha.

Portão de segurança

Leitura livre. build, run, push, rm exigem confirmação — docker system prune é destrutivo.

Otimização — na ordem que rende

# Técnica Ganho típico
1 Multi-stage — build separado do runtime o maior de todos
2 Ordem das camadas — dependência antes do código cache aproveitado
3 Base slim/alpine (cuidado com glibc/musl) 100s de MB
4 .dockerignore build context menor
5 --no-install-recommends, limpar apt lists dezenas de MB
6 Um RUN para instalar+limpar evita camada com lixo

Camada só cresce: RUN apt install seguido de RUN apt clean em linhas separadas não reduz nada — o lixo já está na camada anterior.

Padrão multi-stage

FROM node:20-slim AS build
WORKDIR /app
COPY package*.json ./          # dependência primeiro: cache
RUN npm ci
COPY . .
RUN npm run build

FROM node:20-slim
WORKDIR /app
RUN useradd -r -u 1001 app     # não rode como root
COPY --from=build --chown=app /app/dist ./dist
COPY --from=build --chown=app /app/node_modules ./node_modules
USER app
HEALTHCHECK CMD curl -f http://localhost:3000/health || exit 1
CMD ["node","dist/main.js"]

Segurança

  • Nunca USER root no runtime
  • Nunca segredo em ARG ou ENV — fica na imagem e no histórico
  • Fixe a tag base (node:20.11-slim, não node:latest)
  • trivy image X antes de publicar
  • .dockerignore com .env, .git, node_modules

Segredo passado em --build-arg fica no histórico da imagem. Quem tem a imagem tem o segredo. Use BuildKit secrets ou injete em runtime.

Diagnóstico

Sintoma Verificar
Imagem enorme dive — qual camada pesa
Build lento ordem das camadas, .dockerignore
Funciona local, quebra no cluster arquitetura (arm64 vs amd64), env, volume
Container reinicia docker logs, exit code, healthcheck
Permissão negada UID do processo vs. dono do volume

Read the full file on GitHub · 82 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 82 lines · 65 tokens per session scan A 8ca842d94a53

Subscribe to this mod's changes

docker-specialist is a skill published in the GitHub repository pwdev-solucoes/pwdev-claude-marketplace (2 stars, last pushed yesterday), licensed Apache-2.0. It adds 65 tokens to every session and 793 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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