Marketplace c4-modeling

C4 architectural modeling for documenting software architecture. Use when creating architecture diagrams, planning new systems, communicating with stakeholders, or conducting architecture reviews.

install

source · Clone the upstream repo

git clone https://github.com/aiskillstore/marketplace

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/aiskillstore/marketplace "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/consiliency/c4-modeling" ~/.claude/skills/aiskillstore-marketplace-c4-modeling && rm -rf "$T"

manifest: skills/consiliency/c4-modeling/SKILL.md

source content

C4 Modeling Skill

Create hierarchical architecture diagrams at four abstraction levels using the C4 model and Mermaid syntax.

Variables

Variable Default Description

DEFAULT_LEVEL

context

Start with

context

container

component

, or

code

OUTPUT_FORMAT

mermaid

mermaid

structurizr

plantuml

INCLUDE_LEGEND true Add legend to diagrams

Instructions

MANDATORY - Follow the Workflow steps below when creating C4 diagrams.

Always start at Level 1 (Context) and zoom in as needed
Never mix abstraction levels in a single diagram
Include descriptions for all elements

Red Flags - STOP and Reconsider

If you're about to:

Create a container diagram without first creating a context diagram
Mix containers and components in the same diagram
Show implementation details at the context level
Create a code-level diagram for non-critical code

STOP -> Check the appropriate level guidelines in

reference/level-guidelines.md

-> Then proceed

Workflow

Determine the audience and purpose
CHECKPOINT: Start at Level 1 (Context) unless you have higher-level diagrams
Identify all actors and systems at current level
Define relationships with labeled arrows
Add technology choices (for Level 2+)
CHECKPOINT: Verify you haven't mixed abstraction levels
Include descriptions for clarity

C4 Levels

Level	Name	Purpose	Audience
1	Context	System in environment	Everyone
2	Container	Major components	Technical stakeholders
3	Component	Internal structure	Developers
4	Code	Implementation	Developers (sparingly)

Quick Reference

Level 1: Context

Show: System, users, external systems Hide: Internal details, databases, technology

Level 2: Container

Show: Applications, APIs, databases, queues Hide: Internal structure, classes

Level 3: Component

Show: Modules, services, repositories Hide: Individual classes, functions

Level 4: Code

Show: Classes, interfaces, key abstractions Use: Only for complex/critical areas

See

reference/level-guidelines.md

for detailed guidance. See

reference/mermaid-syntax.md

for Mermaid C4 syntax.

Mermaid Quick Syntax

C4Context
    title System Context Diagram
    Person(user, "User", "Description")
    System(system, "System", "Description")
    System_Ext(ext, "External", "Description")
    Rel(user, system, "Uses")

C4Container
    title Container Diagram
    Container(web, "Web App", "React", "UI")
    Container(api, "API", "Node.js", "Backend")
    ContainerDb(db, "Database", "PostgreSQL", "Storage")
    Rel(web, api, "Calls", "REST")

See

reference/mermaid-syntax.md

for complete syntax reference.

Output

Diagrams should include:

Title indicating level and system
All relevant elements with descriptions
Labeled relationships
Technology choices (Level 2+)
Clear boundaries for grouping