docker-image-hardening

docker-image-hardening is a skill for Claude Code from FluxonLab/Skillry. It costs 54 tokens per session (2,026 once invoked), scanned A, original, no licence file.

A checklist and authoring guide for safer Docker images. Docker packages an application and its dependencies into a portable image that can run in different environments.

In plain words
What is it for?
It helps write or review Dockerfiles using multi-stage builds, small base images, non-root users, pinned versions, vulnerability scans, and software bills of materials.
Why use it?
It reduces image size, security risks, and accidental exposure of files or credentials while keeping builds repeatable.

Skill for Claude Code

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

Part of the skillry-cloud-and-infrastructure plugin — 6 skills, 2 agents shipped together

Good fit It helps write or review Dockerfiles using multi-stage builds, small base images, non-root users, pinned versions, vulnerability scans, and software bills of materials.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fluxonlab/skillry/332-docker-image-hardening
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 FluxonLab/Skillry --skill 332-docker-image-hardening
Clone the repo
git clone --depth 1 https://github.com/FluxonLab/Skillry

Made for: Claude Code.

Or install skillry-cloud-and-infrastructure, the plugin that ships this one along with the rest of its 6 skills, 2 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-image-hardening

README.md
[![agentmods](https://agentmods.dev/badge/skills/fluxonlab/skillry/332-docker-image-hardening/github.svg)](https://agentmods.dev/skills/fluxonlab/skillry/332-docker-image-hardening)
Your own site
<a href="https://agentmods.dev/skills/fluxonlab/skillry/332-docker-image-hardening"><img src="https://agentmods.dev/badge/skills/fluxonlab/skillry/332-docker-image-hardening/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-image-hardening

Your own site · 80×15
<a href="https://agentmods.dev/skills/fluxonlab/skillry/332-docker-image-hardening"><img src="https://agentmods.dev/badge/skills/fluxonlab/skillry/332-docker-image-hardening.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,026 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 unknown 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 $0.00054 $0.02026
Opus 5 $0.00027 $0.01013
Sonnet 5 $0.00011 $0.00405
Haiku 4.5 $0.00005 $0.00203

Measured 6d ago against content hash 2e5c943454ee, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

docker-image-hardening 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 6d 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.

- [ ] No unnecessary build tools (compilers, curl, package managers) remain in the final stage.
plugins/cloud-and-infrastructure/skills/332-docker-image-hardening/SKILL.md · 176 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 6d ago First seen · 176 lines · 54 tokens per session scan A 2e5c943454ee

Subscribe to this mod's changes

docker-image-hardening is a skill published in the GitHub repository FluxonLab/Skillry (2 stars, last pushed 12d ago), with no licence file. It adds 54 tokens to every session and 2,026 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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