CtrlK
BlogDocsLog inGet started
Tessl Logo

c4-container

Expert C4 Container-level documentation specialist.

49

2.75x
Quality

22%

Does it follow best practices?

Impact

99%

2.75x

Average score across 3 eval scenarios

SecuritybySnyk

Passed

No findings from the security scan

Fix and improve this skill with Tessl

tessl review fix ./plugins/AI-Agents-Safe-Coding-Skills-claude/skills/c4-container/SKILL.md

The canonical home for this skill is c4-container in sickn33/agentic-awesome-skills

SKILL.md
Quality
Evals
Security

Quality

Content

22%Scale 1-3

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

This skill reads more like a documentation template than an actionable skill for Claude. It's filled with placeholder brackets and boilerplate that Claude already knows how to generate (OpenAPI specs, Mermaid C4 diagrams), while lacking a clear workflow for actually producing container-level documentation. The instructions section is too generic to guide Claude through the specific task of synthesizing C4 container documentation.

Suggestions

Replace the generic 4-bullet instruction list with a concrete step-by-step workflow: e.g., 1) Identify deployment units from code/config, 2) Map components to containers, 3) Document interfaces, 4) Generate diagram, 5) Validate completeness against checklist.

Remove or drastically shorten the OpenAPI template and Mermaid boilerplate—Claude knows these formats. Instead, specify only the C4-specific conventions and constraints that differ from standard usage.

Add validation checkpoints to the workflow, such as 'Verify each container has at least one interface documented' or 'Confirm all inter-container relationships appear in the Mermaid diagram'.

Move the template scaffolding (container template, API spec template) into a separate reference file and keep SKILL.md focused on the decision-making process and workflow.

DimensionReasoningScore

Conciseness

The skill is heavily padded with template placeholders (e.g., '[Container Name]', '[Description]') that don't provide actionable guidance. It explains concepts Claude already knows (what REST/GraphQL are, what containers are in C4) and includes verbose boilerplate like the full OpenAPI template and Mermaid diagram syntax that Claude can generate on its own.

1 / 3

Actionability

The Mermaid diagram example and OpenAPI spec template are concrete and copy-paste ready, which is good. However, most of the content is template scaffolding with placeholder brackets rather than executable instructions. The 'Instructions' section is extremely vague ('Clarify goals, constraints, and required inputs').

2 / 3

Workflow Clarity

There is no clear multi-step workflow or sequenced process for creating container documentation. The instructions are four bullet points of generic advice with no validation checkpoints. The 'Example Interactions' section lists prompts but doesn't describe a process for synthesizing container documentation.

1 / 3

Progressive Disclosure

There is a reference to 'resources/implementation-playbook.md' and mentions of component documentation links, showing some awareness of progressive disclosure. However, the main file itself is a monolithic wall of templates that could be split into separate reference files, and the single external reference is vaguely signaled.

2 / 3

Total

6

/

12

Passed

Description

22%Scale 1-3

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

This description is extremely terse and relies on buzzwords ('Expert', 'specialist') rather than concrete actions. It fails to explain what the skill actually does or when it should be selected, making it nearly useless for skill selection among a large pool of available skills.

Suggestions

Replace vague terms like 'specialist' with concrete actions such as 'Generates C4 Container diagrams, documents system containers and their interactions, creates PlantUML or Structurizr DSL representations'.

Add an explicit 'Use when...' clause, e.g., 'Use when the user asks about C4 architecture diagrams, container views, system architecture documentation, or mentions C4 model.'

Include natural trigger terms users would say, such as 'architecture diagram', 'container diagram', 'C4 model', 'system design documentation', 'Structurizr', or 'PlantUML'.

DimensionReasoningScore

Specificity

The description uses vague language with no concrete actions listed. 'Expert' and 'specialist' are buzzwords that don't describe what the skill actually does (e.g., generate diagrams, write documentation, create container views).

1 / 3

Completeness

The description barely addresses 'what' (documentation specialist) and completely lacks any 'when' clause or explicit trigger guidance. There is no 'Use when...' or equivalent.

1 / 3

Trigger Term Quality

'C4' and 'Container-level' are relevant domain keywords that a user familiar with C4 modeling would use, but common variations like 'architecture diagram', 'system context', 'PlantUML', or 'Structurizr' are missing.

2 / 3

Distinctiveness Conflict Risk

'C4 Container-level' provides some specificity that distinguishes it from generic documentation skills, but 'documentation specialist' is broad enough to overlap with other documentation-related skills.

2 / 3

Total

6

/

12

Passed

Validation

90%

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

Validation10 / 11 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

10

/

11

Passed

Repository
administrakt0r/AI-Agents-Safe-Coding-Skills
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.