CtrlK
BlogDocsLog inGet started
Tessl Logo
SkillPublic

nic-docker-images

Docker image build system, Dockerfile structure, image variants, build scripts, and Makefile targets for NIC. Use when building container images, modifying the Dockerfile, adding new image variants, debugging image builds, or working with build scripts.

Quality

85%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide
SecuritybySnyk

Passed

No findings from the security scan

SKILL.md
Quality
Evals
Security

Quality

Content

82%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

An excellent reference-style skill body: dense, accurate, repo-specific knowledge delivered as tables, exact commands, and path-level detail, with the tricky agent v2/v3 pairing explained and a concrete checklist for adding variants. It is slightly heavy for a single SKILL.md (tables that mirror the Makefile), lacks any post-build validation step, and leans on one fragile repo-relative link instead of bundled references.

Suggestions

Move the 25-row Makefile target table and the Key Build Args table into a bundled reference file (e.g. references/targets.md) and keep only the three-axis variant summary in SKILL.md, reducing token load on every invocation.

Add a validation step to the build workflow (e.g. after building, verify with `docker run --rm <image> nginx -v` or the Python e2e `agentv2`/`agentv3` markers) to create a feedback loop for batch builds.

Replace the fragile relative link `../../../docs/developer/image-matrices.md` with a bundled copy of the add-an-image checklist so the skill is self-contained and the reference is one level deep.

DimensionReasoningScore

Conciseness

Nearly every token is non-obvious distilled knowledge — dense tables, exact paths, no explanations of concepts Claude already knows — and it follows its own rule ('Do not hard-code IC_VERSION... values in this file'). Not 5: the 25-row Makefile target table and Key Build Args table largely duplicate machine-readable Makefile content, and time-sensitive labels like 'Debian 13 (trixie), Alpine 3.24, UBI 10 minimal' will go stale.

4 / 5

Actionability

Guidance is fully concrete and executable: exact commands ('make all-images', 'make ubi10-dependency-image-local (requires rhel_license)'), the literal docker build invocation ('docker build --platform linux/$(ARCH) --target $(TARGET) -f build/Dockerfile'), precise file paths ('.github/data/matrix-images-nap.json', 'build/dependencies/Dockerfile.ubi10'), and specific version-pinning rules (UBI10_PACKAGES_IMAGE digest bump). Common cases — building, adding a variant, debugging — are all covered with specifics.

5 / 5

Workflow Clarity

The main multi-step task has an explicit checklist ('a matching foo-nap-agent stage, a Makefile target, an entry in make all-images, and both entries in .github/data/matrix-images-nap.json') plus a pointer to the add-an-image checklist, and the agent v2/v3 pairing is carefully disambiguated. Not 5: no validation/verification steps or feedback loops for batch builds — nothing says how to verify an image after 'make all-images' prunes the cache and builds 25 variants.

4 / 5

Progressive Disclosure

Well-organized single-file structure with clearly labeled sections and one clearly signaled external reference ('Matrix row schema and the checklist for adding an image: [docs/developer/image-matrices.md]'). No bundle files exist, so everything is inlined; not 5 because the heavy target/args tables could be split into a reference file and the single link uses a fragile repo-relative path ('../../../docs/developer/image-matrices.md') rather than a bundled, stable reference.

4 / 5

Total

17

/

20

Passed

Description

83%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description: concrete topic list plus an explicit five-trigger 'Use when...' clause in third person, with no fluff or over-claims. The main gaps are the absence of synonyms/expansions ('docker build', the unabbreviated product name for 'NIC') and a couple of generic trigger phrases that slightly raise conflict risk with general build-related skills.

DimensionReasoningScore

Specificity

Lists several specific capability areas — 'Dockerfile structure, image variants, build scripts, and Makefile targets for NIC' — going well beyond 1-2 concrete items, but they are noun-phrase topics rather than the concrete action verbs of the top anchor ('Extract text... fill forms... merge documents'), leaving minor gaps in action coverage.

4 / 5

Completeness

Explicitly answers both: the 'what' is a concrete list ('Docker image build system, Dockerfile structure, image variants, build scripts, and Makefile targets for NIC') and the 'when' is an explicit 'Use when...' clause with five concrete trigger phrases, matching the anchor-5 example structure. Not 4 because the 'when' clause is already fully explicit and specific.

5 / 5

Trigger Term Quality

'building container images, modifying the Dockerfile, adding new image variants, debugging image builds, or working with build scripts' are phrases a user would naturally say, giving good keyword coverage. Not 5: no synonyms or expansions are offered — e.g. 'docker build', 'base image', or the unabbreviated 'NGINX Ingress Controller' behind 'NIC'.

4 / 5

Distinctiveness Conflict Risk

The niche is clear — NIC's Docker image build system, anchored by distinct triggers like 'Dockerfile', 'image variants', and 'Makefile targets'. Not 5: the generic phrases 'building container images' and 'working with build scripts' carry minor overlap risk with general Docker/build skills; not 3 since the overall framing is unmistakably about this repo's image builds.

4 / 5

Total

17

/

20

Passed

Validation

93%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

relative_links

Relative link issues: 1 suspicious

Warning

Total

15

/

16

Passed

Repository

nginx/kubernetes-ingress

Path

.github/skills/nic-docker-images/SKILL.md

Reviewed

Table of Contents

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.