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Create technical diagrams using Mermaid syntax for architecture, sequences, ERDs, flowcharts, and state machines. Use for visualizing system design, data flows, and processes. Triggers: diagram, mermaid, architecture diagram, sequence diagram, flowchart, ERD, entity relationship, state diagram, C4 model, component diagram, visualize, draw.

Install Skill

1Download skill
2Enable skills in Claude

Open claude.ai/settings/capabilities and find the "Skills" section

3Upload to Claude

Click "Upload skill" and select the downloaded ZIP file

Note: Please verify skill by going through its instructions before using it.

SKILL.md

name diagramming
description Creates Mermaid and ASCII diagrams for flowcharts, architecture, ERDs, state machines, mindmaps, and more. Use when user mentions diagram, flowchart, mermaid, ASCII diagram, text diagram, terminal diagram, visualize, C4, mindmap, architecture diagram, sequence diagram, ERD, or needs visual documentation.

Diagram Generator

Expert skill for creating clear, professional diagrams in Mermaid or ASCII format.

Supported Formats

Format Best For Trigger Keywords
Mermaid Web docs, GitHub, rich rendering "diagram", "mermaid", "visualize"
ASCII Terminals, plain text, emails "ASCII", "text diagram", "terminal"

Diagram Types

graph/flowchart     - Flowcharts and decision trees
sequenceDiagram     - API interactions and workflows
classDiagram        - Object-oriented structures
stateDiagram-v2     - State machines and transitions
erDiagram           - Database relationships
C4Context/C4Container/C4Component - Architecture views (C4 model)
mindmap             - Brainstorming and idea organization
block-beta          - System block diagrams
gantt               - Project timelines
pie                 - Data distributions
gitGraph            - Git branching strategies
journey             - User experience flows
quadrantChart       - Priority matrices
timeline            - Historical events

Quick Start

  1. Determine format: Mermaid (default) or ASCII (if user explicitly requests)
  2. Select diagram type based on what's being visualized
  3. Choose layout: TB/TD (top-down), LR (left-right) for Mermaid
  4. Keep readable: Max 15-20 nodes per diagram
  5. Apply meaningful styling: Colors/shapes with semantic meaning

Output Format

Mermaid (Default)

```mermaid
graph TD
    A[Start] --> B{Decision}
    B -->|Yes| C[Action 1]
    B -->|No| D[Action 2]

    classDef success fill:#90EE90
    class C success
```

ASCII (When Explicitly Requested)

+-------+     +----------+
| Start | --> | Decision |
+-------+     +----+-----+
                   |
         +---------+---------+
         |                   |
         v                   v
    +----------+       +----------+
    | Action 1 |       | Action 2 |
    +----------+       +----------+

ASCII Conventions:

  • +---+ for boxes, | for vertical lines, --> or --- for connections
  • Use consistent spacing and alignment
  • Label arrows with [text] above the line when needed

Diagram Type Selection

Use Case Recommended Type
Process/decision flow graph (flowchart)
API/service interactions sequenceDiagram
System architecture (high-level) C4Context
System architecture (detailed) C4Container, block-beta
Database schema erDiagram
Brainstorming/ideas mindmap
State transitions stateDiagram-v2
Project timeline gantt
Feature prioritization quadrantChart

Resources

Integration

  • Auto-invokes on trigger keywords (diagram, mermaid, ASCII, visualize, etc.)
  • Manual: Use /diagram command
  • With docs: Works alongside doc-coauthoring skill for documentation diagrams