Container Build

Container Build is a skill for Claude Code, Codex from niels-emmer/myace. It costs 23 tokens per session (283 once invoked), scanned A, original, MIT.

A guide for building small, secure, repeatable production container images. Containers package an application and its runtime so it can run consistently across environments.

In plain words
What is it for?
Use it to create multi-stage Dockerfiles, run as a non-root user, pin base images, scan for vulnerabilities, and tag images with versions or commit identifiers.
Why use it?
It reduces image size, limits security exposure, improves build caching, and makes deployed images easier to reproduce and scan.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for aider. Also seen: mentions Codex; built for aider; mentions OpenCode.

Good fit Use it to create multi-stage Dockerfiles, run as a non-root user, pin base images, scan for vulnerabilities, and tag images with versions or commit identifiers.

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Install with agentmods
npx agentmods add skills/niels-emmer/myace/container-build
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 niels-emmer/myace --skill container-build
Clone the repo
git clone --depth 1 https://github.com/niels-emmer/myace

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 Container Build

README.md
[![agentmods](https://agentmods.dev/badge/skills/niels-emmer/myace/container-build/github.svg)](https://agentmods.dev/skills/niels-emmer/myace/container-build)
Your own site
<a href="https://agentmods.dev/skills/niels-emmer/myace/container-build"><img src="https://agentmods.dev/badge/skills/niels-emmer/myace/container-build/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 Container Build

Your own site · 80×15
<a href="https://agentmods.dev/skills/niels-emmer/myace/container-build"><img src="https://agentmods.dev/badge/skills/niels-emmer/myace/container-build.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 283 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.
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 $0.00023 $0.00283
Opus 5 $0.00012 $0.00142
Sonnet 5 $0.00005 $0.00057
Haiku 4.5 $0.00002 $0.00028

Measured 9d ago against content hash e22a1ca2a639, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

Container Build 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 9d 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.

collections/additional/devops/skills/container-build/SKILL.md · 26 lines

What it actually says

Purpose

Build containers that are small, secure, and reproducible.

Checklist

  • Multi-stage builds: build stage with full SDK, production stage with only runtime deps.
  • Base image: prefer distroless or scratch for production; use Alpine as a pragmatic minimum.
  • Layer caching: order Dockerfile instructions from least to most frequently changing (deps first, code last).
  • Non-root user: production containers run as a non-root user, not root.
  • Vulnerability scanning: scan images for CVEs before pushing to registry (trivy, grype, or equivalent).
  • Image tagging: tag with commit SHA + semantic version; latest is never used in production.
  • Reproducible builds: pin base image digests, not tags.

Expected output

A Dockerfile producing minimal, scanned, non-root containers with pinned base images and multi-stage separation.

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 · 26 lines · 23 tokens per session scan A e22a1ca2a639

Subscribe to this mod's changes

Container Build is a skill published in the GitHub repository niels-emmer/myace (1 stars, last pushed 3d ago), licensed MIT. It adds 23 tokens to every session and 283 once invoked, about $0.0001 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 2026-08-31.