Dockerfile

Skill andypitcher/ponytail-sec/skills/dockerfile

Binary Dockerfile image-build hardening check. Use when reviewing Dockerfiles, container image builds, multi-stage builds, runtime users, pinned bases, or reproducible dependency installs. Minimal output only: OK or NOT_OK: RULE, RULE.From its SKILL.md

Install

npx -y skills add andypitcher/ponytail-sec --skill dockerfile

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

8 stars8 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

What its file declares

Copied from the file, not written here

The file declares its own license as MIT. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

1.4 KB, as published. Nobody here has run it

Ask once before enforcing:

Enforce dockerfile skill? (yes / no)

If no: stop.

If yes: inspect locally. Do not web-search by default. Web-search only if the user asks or the Dockerfile uses a platform feature whose semantics are unknown.

Contract

Return exactly one line:

OK
NOT_OK: RULE, RULE

No severity. No advisory text. No maybes. If a rule cannot be verified, it is not OK.

Rules

All rules are mandatory.

NON_ROOT — final image must set USER to a non-root user or numeric UID that is not 0.
MULTI_STAGE — production Dockerfile must use more than one FROM and copy only the runtime result into the final stage.
LEAN_FINAL — final stage must not install or retain package managers, compilers, build tools, caches, or test tooling.
PIN_BASE — every FROM must be pinned to a non-floating tag or digest; no latest, no untagged images. Digest wins.
REPRO_DEPS — dependency installation must use reproducible inputs: lockfile, hash-pinned requirements, vendor directory, or equivalent. Raw manifest-only installs are not OK.

Output examples

OK

NOT_OK: NON_ROOT, PIN_BASE, REPRO_DEPS