Container Supply Chain - Production Implementation Guide Agent Skill

Production implementation guide for new container image supply-chain security: OCI image signing, digest-first builds, GitHub artifact…

Context cost
12.7k tokensestimated from the bundle, loaded when it triggers
Bundle
3 files · 50.6 kBtext throughout, nothing executable
Licence
MITthe author’s own terms
Last change
—no release on file
Servers it uses
Noneruns standalone

What it does

Production implementation guide for new container image supply-chain security: OCI image signing, digest-first builds, GitHub artifact attestations, Cosign keyless signing, optional Notation/ACR signing, Rekor audit lookup, SBOM generation and attestation, vulnerability scanning, waiver governance, SLSA Build track evidence, deployment admission gates, and artifact-leakage prevention.

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

githubsecuritytesting

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md37.4 kB · preview
--- name: container-supply-chain compatibility: >- Assumes new projects. Prefer current Docker Buildx/build-push-action, Cosign v2+, GitHub artifact attestations, Syft, Grype, Trivy, and OCI registries that support signatures/referrers. Verify current tool versions, CLI flags, registry support, and cloud-provider guidance before enforcement. metadata: owner: platform-engineering lastReviewed: "2026-07-29" last_verified: "2026-07-29" ---
24# Container Supply Chain - Production Implementation Guide
25
26Use this skill to design or implement a secure container release path from source
27through deployment. Optimize for new projects: do not preserve legacy Docker
28Content Trust, mutable production tags, unsigned images, or CI-only trust checks
29unless the task explicitly requires migration support.
30
31For policy rules, pair this skill with your repository's Docker supply-chain
32and GitHub Actions security standards (workflow hardening, OIDC federation,
33action pinning, artifact hygiene).
34
35## Use When
36
37| Should trigger | Should NOT trigger | Nearby skill collision |
38| --- | --- | --- |
39| Designing or hardening a build-sign-attest-scan-verify pipeline for OCI images | The task is only about runtime debugging, container startup, or incident triage after deployment | Use container-operations for runtime/container failure diagnosis |
40| Implementing image signing, provenance, SBOM, attestation verification, or deployment trust gates | The task is only about Dockerfile authoring with no supply-chain trust or artifact-leakage scope | Use Docker/container authoring guidance unless release trust is in scope |
41| Producing audit-ready release evidence, waiver governance, or admission-policy checks for container artifacts | The request is only about registry cleanup or lifecycle retention unrelated to signatures/attestations | Use ACR lifecycle/registry skills when trust metadata is not the main concern |
42
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md4,697 words
Files3
LicenceMIT
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈290
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
12,360
on trigger
The instruction body and 2 supporting files, read only when the skill fires.
6.3%
of a 200k window
Ten skills this size would take about 63% of the window before you open a file.
050k100k150k200k context window

12.7k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

Its SKILL.md does not declare which tools it asks the agent for, so what it touches is whatever the instructions themselves ask for — read them before you install it.

What it asks for
Writes filesnot declared
Network accessnot declared

This SKILL.md carries no allowed-tools line, so neither is declared. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

3 files, 50.6 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md37.4 kB
  • CHANGELOG.md4.7 kB
  • references/distribution-artifact-leakage.md8.5 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 3 files you can review in full before installing. The MIT licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Container Supply Chain - Production Implementation Guide · 12.7k tokens when loaded · macOS, Linux mkdir -p .claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/container-supply-chain-production-implementation/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/container-supply-chain-production-implementation" ] && { [ ! -e .claude/skills/container-supply-chain-production-implementation ] || { mv .claude/skills/container-supply-chain-production-implementation "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/container-supply-chain-production-implementation" .claude/skills/ && echo "Installed .claude/skills/container-supply-chain-production-implementation"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add lukemurraynz/container-supply-chain-production-implementation

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/container-supply-chain-production-implementation/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/container-supply-chain-production-implementation/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/container-supply-chain-production-implementation" ] && { [ ! -e ~/.claude/skills/container-supply-chain-production-implementation ] || { mv ~/.claude/skills/container-supply-chain-production-implementation "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/container-supply-chain-production-implementation" ~/.claude/skills/ && echo "Installed ~/.claude/skills/container-supply-chain-production-implementation" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/container-supply-chain-production-implementation/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where. It appears as container-supply-chain in Gemini CLI, Codex, Copilot and Grok (its own name); Claude Code lists it by the folder name, container-supply-chain-production-implementation.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/
Claude DesktopCustomize › Skills
ChatGPTSkills › Create › Upload
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok Build.grok/skills/
Microsoft CopilotSkills › Upload a skill
PerplexityComputer › Skills › Upload a skill
DeepSeek Harness.dsh/skills/
Zed.agents/skills/
Devin Desktop.devin/skills/
Windsurf (legacy).windsurf/skills/
OpenAI Agents SDKInstructions or sandbox Skills
HTTP / APIa request parameter
This release
Versionnot versioned
Publishedno release date on file
PriceFree
Referencelukemurraynz/container-supply-chain-production-implementation

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

Reviews

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