legacy-app-containerize

legacy-app-containerize is a skill for Claude Code from lukasrepublic/agentic-foundry. It costs 0 tokens per session (1,063 once invoked), scanned A, original, MIT.

A procedure for packaging an older application runtime, such as an end-of-life Node.js, Python, or Ruby version, into a container image. It covers checks and fixes for common build failures during a lift-and-shift migration.

In plain words
What is it for?
Use it when containerizing a legacy application, checking lockfiles and dependency installs, setting a non-root runtime user, preserving required state paths, and diagnosing image-build errors.
Why use it?
It helps prevent builds from breaking because dependencies change, files have wrong permissions, native packages cannot compile, or the container build system fails. It keeps the old runtime unchanged while moving the application into a container.

Skill for Claude Code

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

Part of the foundry plugin — 81 skills, 8 agents, 8 hooks, 1 MCP server shipped together

Good fit Use it when containerizing a legacy application, checking lockfiles and dependency installs, setting a non-root runtime user, preserving required state paths, and diagnosing image-build errors.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/lukasrepublic/agentic-foundry/legacy-app-containerize
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 lukasrepublic/agentic-foundry --skill legacy-app-containerize
Clone the repo
git clone --depth 1 https://github.com/lukasrepublic/agentic-foundry

Made for: Claude Code.

Or install foundry, the plugin that ships this one along with the rest of its 81 skills, 8 agents, 8 hooks, 1 MCP server.

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 legacy-app-containerize

README.md
[![agentmods](https://agentmods.dev/badge/skills/lukasrepublic/agentic-foundry/legacy-app-containerize.svg)](https://agentmods.dev/skills/lukasrepublic/agentic-foundry/legacy-app-containerize)
Your own site
<a href="https://agentmods.dev/skills/lukasrepublic/agentic-foundry/legacy-app-containerize"><img src="https://agentmods.dev/badge/skills/lukasrepublic/agentic-foundry/legacy-app-containerize.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,063 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 $0.00000 $0.01063
Opus 5 $0.00000 $0.00531
Sonnet 5 $0.00000 $0.00213
Haiku 4.5 $0.00000 $0.00106

Measured 7d ago against content hash aa81bee6c4e9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

legacy-app-containerize 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 7d 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.

packs/stack-profiles/aws-eks-karpenter/blueprints/legacy-app-containerize/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to trigger

  • Containerizing an application pinned to an end-of-life runtime major (old Node.js/Python/Ruby) as-is for a lift-and-shift migration (runtime upgrade is a separate project).
  • A legacy-app image build failing with parser errors in .d.ts files, engine-floor install errors, "no rule to make target" in a post-install hook, EACCES on first write, or a BuildKit GOAWAY during export.

Inputs: source repo; the pinned runtime + major (e.g. node:16.20.1); package manager + install verb; the non-root runtime UID; runtime state paths; the registry immutability policy (tag == SHA).

Pre-flight checks (run BEFORE the first build; each maps to a fleet-recurrent gotcha)

  • lockfile-committed — a lockfile exists AND is committed. Install-at-build with no lockfile carries a latent transitive-version float: the image builds today and hard-breaks on the next rebuild when a ^-ranged transitive floats. When the manifest and lockfile are OUT OF SYNC, make a surgical single-entry lockfile edit of only the drifted entry (when the two versions have identical dependency trees) — never a fresh install, which re-floats every transitive dep and reintroduces the stub-float and engine-floor gotchas.
  • type-stub-pinned-to-runtime — pin @types/<runtime>-style stubs to the RUNTIME's major (e.g. ^16 stubs for a v16 runtime). An unpinned stub floats to a modern major whose .d.ts uses syntax the old compiler's PARSER rejects (parse errors, not type errors) — and --skipLibCheck does NOT rescue it: it skips .d.ts type-CHECKING but still PARSES every .d.ts.
  • engine-floor-vs-runtime — scan the resolved tree for engines floors above the pinned runtime. A strict/frozen install ERRORS on the mismatch (the legacy environment only warned). Prescribe the ignore-engines flag while keeping the lockfile frozen, and track the EOL runtime as a pre-production residual — never unfreeze to dodge the error.
  • build-file-in-deps-layer — a post-install/native hook's referenced files are in the dependency-layer COPY set. A hook running make … during install fails "no rule to make target" when the deps layer COPYed only manifest + lockfile + registry config — layer-ordering correctness, not a toolchain bug.
  • workdir-writable-for-nonroot — if the app writes runtime state under WORKDIR and runs non-root, chown the state path for the runtime UID — a root-owned WORKDIR gives EACCES on the first write of a file-backed embedded store.

Read the full file on GitHub · 66 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. 7d ago First seen · 66 lines · 0 tokens per session scan A aa81bee6c4e9

Subscribe to this mod's changes

legacy-app-containerize is a skill published in the GitHub repository lukasrepublic/agentic-foundry (1 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,063 tokens. 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.

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