/SKILL

PURPOSE

Render a diagram from Mermaid, Graphviz, D2, PlantUML, or Python diagrams source code to a PNG file using local renderers — no internet access required.

RENDERERS

Type	CLI Tool	Auto-detected By	Best For	When to Use
mermaid	mmdc (npm)	graph, sequenceDiagram, C4Context, etc.	Sequence, flowcharts, simple C4	Quick inline diagrams in markdown/docs; sequence flows; already in markdown
graphviz	dot (graphviz)	digraph, graph {, strict digraph	General graphs, dependency trees	When splines=ortho edge routing or precise DOT control is needed
d2	d2 CLI	explicit --type d2 only	Architecture diagrams — cleanest layout	Default choice for service/container architecture diagrams
plantuml	plantuml CLI	@startuml	Full C4 model with Person/System icons	When formal C4 notation with icons is required (C4Context, C4Container)
diagrams	python3 + diagrams pkg	from diagrams import, from diagrams.	Cloud infra with AWS/Azure/GCP icons	AWS, Azure, GCP, Kubernetes infrastructure visualization

EXECUTION

1. Detect Renderer: Use --type or auto-detect from code syntax
2. Generate PNG: Run ./scripts/generate-diagram.py <code> <output> [type]
3. Return Path: Confirm PNG written to --output

D2 note: uses --layout=elk by default for minimal edge crossings.

DELEGATION

MANDATORY: Always invoke the agents defined in this command's frontmatter.

• zzaia-document-specialist — Executes diagram generation workflow

WORKFLOW

sequenceDiagram
    participant U as User
    participant C as Command
    participant P as Python Script
    participant F as File System

    U->>C: /capability:diagram:generate --code <code> --output <path> [--type]
    C->>P: Execute generate-diagram.py
    P->>P: Auto-detect or use explicit renderer
    P->>F: Write PNG to output path
    P-->>C: PNG path + size
    C-->>U: Diagram ready

EXAMPLES

# Mermaid — quick inline sequence/flowchart (auto-detected)
/capability:diagram:generate --code "graph TD\n A --> B --> C" --output ./diagrams/flow.png

# Graphviz — dependency trees, graph analysis, splines=ortho routing
/capability:diagram:generate --type graphviz --code "digraph { rankdir=TB; splines=ortho; A -> B -> C }" --output ./diagrams/arch.png

# D2 + ELK — default choice for service/container architecture diagrams
/capability:diagram:generate --type d2 --code "direction: down\nwasm -> bff: GraphQL\nbff -> order: HTTP/Dapr\nbff -> identity: HTTP/Dapr" --output ./diagrams/arch.png

# PlantUML — formal C4 model with Person/System/Container icons
/capability:diagram:generate --type plantuml --code "@startuml\n!include C4Container.puml\nPerson(u, \"User\")\nSystem(s, \"System\")\nRel(u, s, \"Uses\")\n@enduml" --output ./diagrams/c4.png

# Diagrams (Python) — AWS/Azure/GCP/Kubernetes cloud infrastructure with provider icons
/capability:diagram:generate --type diagrams --code "from diagrams import Diagram, Cluster\nfrom diagrams.azure.compute import AppService\nfrom diagrams.azure.database import SQLDatabase\nwith Diagram('CoffeeShop'):\n    with Cluster('Services'):\n        svc = AppService('Order')\n    db = SQLDatabase('PostgreSQL')\n    svc >> db" --output ./diagrams/infra.png

OUTPUT

• PNG file at --output path
• Confirmation message with renderer used and file size