dockerfile-optimise

dockerfile-optimise is a skill for Claude Code, Codex from pproenca/dot-skills. It costs 73 tokens per session (1,709 once invoked), scanned A, original, MIT.

Guidance for writing and reviewing Dockerfiles, which describe how to build software container images. It covers build structure, caching, image size, dependencies, security, and validation.

In plain words
What is it for?
Use it when creating, optimizing, or reviewing Dockerfiles and container image builds.
Why use it?
It helps avoid slow builds, oversized images, unsafe secret handling, and other common container build problems.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when creating, optimizing, or reviewing Dockerfiles and container image builds.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pproenca/dot-skills/dockerfile-optimise
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 pproenca/dot-skills --skill dockerfile-optimise
Clone the repo
git clone --depth 1 https://github.com/pproenca/dot-skills

Made for: Claude Code, Codex.

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 dockerfile-optimise

README.md
[![agentmods](https://agentmods.dev/badge/skills/pproenca/dot-skills/dockerfile-optimise/github.svg)](https://agentmods.dev/skills/pproenca/dot-skills/dockerfile-optimise)
Your own site
<a href="https://agentmods.dev/skills/pproenca/dot-skills/dockerfile-optimise"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/dockerfile-optimise/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 dockerfile-optimise

Your own site · 80×15
<a href="https://agentmods.dev/skills/pproenca/dot-skills/dockerfile-optimise"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/dockerfile-optimise.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,709 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
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 $0.00073 $0.01709
Opus 5 $0.00036 $0.00855
Sonnet 5 $0.00015 $0.00342
Haiku 4.5 $0.00007 $0.00171

Measured 5d ago against content hash dde4627a36d8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

dockerfile-optimise scanned grade A with 0 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 5d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/.experimental/dockerfile-optimise/SKILL.md · 120 lines

How it starts

The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Dockerfile Optimization Best Practices

Comprehensive Dockerfile optimization guide sourced exclusively from official Docker documentation. Contains 48 rules across 8 categories, prioritized by impact to guide automated refactoring and code generation.

When to Apply

Reference these guidelines when:

  • Writing new Dockerfiles or modifying existing ones
  • Optimizing Docker build times (layer caching, cache mounts, context management)
  • Reducing Docker image size (multi-stage builds, minimal base images)
  • Hardening container security (secret mounts, non-root users, attestations)
  • Setting up CI/CD pipelines with Docker builds
  • Reviewing Dockerfiles for anti-patterns

Rule Categories by Priority

Priority Category Impact Prefix
1 Layer Caching & Ordering CRITICAL cache-
2 Multi-Stage Builds CRITICAL stage-
3 Base Image Selection HIGH base-
4 Build Context Management HIGH ctx-
5 Security & Secrets HIGH sec-
6 Dependency Management MEDIUM-HIGH dep-
7 Instruction Patterns MEDIUM inst-
8 Quality & Validation MEDIUM lint-

Quick Reference

1. Layer Caching & Ordering (CRITICAL)

Read the full file on GitHub · 120 lines

Files

What ships with it

50 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. 5d ago First seen · 120 lines · 73 tokens per session scan A dde4627a36d8

Subscribe to this mod's changes

dockerfile-optimise is a skill published in the GitHub repository pproenca/dot-skills (205 stars, last pushed 24d ago), licensed MIT. It adds 73 tokens to every session and 1,709 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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