docker

docker is a skill for Claude Code from EliasOulkadi/shokunin. It costs 111 tokens per session (4,128 once invoked), scanned B, original, MIT.

A guide to building and running applications in Docker, a tool that packages software with the files it needs into isolated containers. It covers image builds, local development, multiple hardware platforms, and container security.

In plain words
What is it for?
Use it to write or improve a Dockerfile, configure Docker Compose, add build caching, build for multiple architectures, run containers without root access, or scan images for vulnerabilities.
Why use it?
It helps reduce oversized images, slow builds, insecure defaults, and deployment differences between machines. It also guides choices such as Docker Compose for simpler applications and Kubernetes-oriented setups for larger deployments.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions OpenCode.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /server ./cmd/server.

Good fit Use it to write or improve a Dockerfile, configure Docker Compose, add build caching, build for multiple architectures, run containers without root access, or scan images for vulnerabilities.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/EliasOulkadi/shokunin
agentmods
npx agentmods add skills/eliasoulkadi/shokunin/docker

Made for: Claude Code.

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/eliasoulkadi/shokunin/docker/github.svg)](https://agentmods.dev/skills/eliasoulkadi/shokunin/docker)
Your own site
<a href="https://agentmods.dev/skills/eliasoulkadi/shokunin/docker"><img src="https://agentmods.dev/badge/skills/eliasoulkadi/shokunin/docker/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

Your own site · 80×15
<a href="https://agentmods.dev/skills/eliasoulkadi/shokunin/docker"><img src="https://agentmods.dev/badge/skills/eliasoulkadi/shokunin/docker.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 111 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,128 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 6 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Tool Misuse · line 254
    Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
    Fix: Limit tool chaining depth and validate the output of each tool before passing it to the next. Require explicit user approval for multi-step chains.
  • medium Server-Side Request Forgery · line 256
    Code issues a request to a loopback, link-local, or private-range host. This can reach internal services not meant to be exposed and is a common SSRF pivot.
    Fix: Avoid requests to loopback/link-local/private hosts from skill code. If internal access is intended, document it and validate the target against an allowlist.
  • medium MCP Rug Pull · line 304
    Docker image references without a specific tag (:latest is implicit) or digest (@sha256:...) can be silently replaced by a malicious image.
    Fix: Pin the image: image:tag or image@sha256:abc123
  • low Tool Misuse · line 271
    Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
    Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
  • low Tool Misuse · line 271
    Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
    Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
  • low Tool Misuse · line 271
    Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
    Fix: Limit tool chaining depth and validate the output of each tool before passing it to the next. Require explicit user approval for multi-step chains.
How audits are shown
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 $0.00111 $0.04128
Opus 5 $0.00056 $0.02064
Sonnet 5 $0.00022 $0.00826
Haiku 4.5 $0.00011 $0.00413

Measured 9d ago against content hash c04d5f9b7f09, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade B, and why

docker scanned grade B with 2 findings 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 9d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/optimize-dockerfile.sh, scripts/scan-image.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Recursive force deletemediumDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

RUN apt-get update && apt-get install -y musl-tools && rm -rf /var/lib/apt/lists/*

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

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

test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
.pack/skills/docker/SKILL.md · 348 lines

How it starts

The opening of the file, as written. The whole thing — 348 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Docker Architect

Production-grade Dockerfiles, multi-stage builds, cache optimization, security scanning, and local development. Applies Google's distroless philosophy and Docker BuildKit best practices.

Decision Framework

Before containerizing, answer:

  • Does the app need process isolation? → Docker
  • Will it deploy to Kubernetes? → Docker + distroless + non-root
  • Is it a monolith with simple deployment? → Docker Compose
  • Is it a static site? → Consider nginx:alpine single-stage
  • Is the team already using Docker Compose in dev? → Start there, add K8s when needed
  • Is the app latency-sensitive (sub-ms)? → Bare metal or VM; container overhead matters at extreme scale

Workflow

Quick start: docker init

For new projects, run docker init in the project root. It auto-detects the language/framework and generates a Dockerfile, .dockerignore, and compose.yaml with best-practice defaults. Always review and harden the output — the generated files are a starting point, not production-ready.

Step 1: Identify stack and choose template

Stack Base image Build stage Runtime
Node.js node:22-slim Full SDK gcr.io/distroless/nodejs
Go golang:1.23-alpine Full SDK scratch
Python python:3.12-slim Full SDK python:3.12-slim
Rust rust:1.78-slim Full SDK gcr.io/distroless/cc

Decision: If the stack is listed above, use the corresponding production Dockerfile below. If not, apply the golden template in Step 2.

Step 2: Apply golden template

Use multi-stage with this exact structure:

Stage 1 (deps):   COPY lock files → install production deps (--mount=type=cache)
Stage 2 (build):  COPY source → compile
Stage 3 (runtime): minimal base → COPY artifacts from stages 1-2 → USER nonroot → HEALTHCHECK

If the project is a Go binary, skip Stage 1 (Go has no runtime deps) and go straight to Stage 2.

If the project has native dependencies (node-gyp, C extensions), use apt-get in the builder stage, NOT the runtime stage.

Read the full file on GitHub · 348 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 9d ago First seen · 348 lines · 111 tokens per session scan B c04d5f9b7f09

Subscribe to this mod's changes

docker is a skill published in the GitHub repository EliasOulkadi/shokunin (113 stars, last pushed 1mo ago), licensed MIT. It adds 111 tokens to every session and 4,128 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it B with 2 findings (recursive force delete, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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