# Mermaid

> Create and edit mermaid diagrams in markdown files. Use when creating flowcharts, sequence diagrams, or any mermaid syntax in .md files.

- Skill: `majiayu000/mermaid-5` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/mermaid-5`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/mermaid-5/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Docs & Writing
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/mermaid-5

---


# Mermaid Diagram Creation

Create professional, color-coded mermaid diagrams with consistent styling for architecture documentation.

## When to Use

- Creating flowcharts, sequence diagrams, or state diagrams
- Documenting architecture or component relationships
- Visualizing workflows or data flows

## Critical Constraints

**ALWAYS:**
- Use the standard color palette defined below
- Include a color legend table after the diagram
- Use `%%{init: {...}}%%` for diagram configuration
- Group related nodes in subgraphs
- Apply class styling to all nodes

**NEVER:**
- Use inline styles (use classDef instead)
- Create diagrams without color coding
- Omit the color legend

---

## Instructions

1. **Identify all nodes**: List every distinct state, action, or decision point

2. **Categorize each node** by type:
   - Input/CLI elements
   - State/Data nodes
   - Handlers/Processors
   - Phase/Control nodes
   - New/Proposed components
   - Output/Artifacts
   - Gaps/Warnings (optional)

3. **Choose direction**: Pick `TB` for hierarchical flows, `LR` for sequential/parallel flows

4. **Assess grouping**: Look for distinct logical phases or stages
   - If phases exist, use subgraphs with descriptive names
   - Keep start/end/error nodes outside subgraphs

5. **Draft the diagram** using the template below

6. **Add color legend table** after the diagram

7. **Review**: Verify all connections and class assignments

---

## Standard Color Palette

| Category | Fill | Stroke | Text | Use For |
|----------|------|--------|------|---------|
| cli | #1a237e | #7986cb | #fff | CLI options, inputs, entry points |
| stateNode | #004d40 | #4db6ac | #fff | State fields, data storage, context |
| handler | #e65100 | #ffb74d | #fff | Handlers, processors, business logic |
| phase | #6a1b9a | #ba68c8 | #fff | Phase nodes, control flow, analysis |
| newComponent | #2e7d32 | #81c784 | #fff | New/proposed components |
| output | #00695c | #4db6ac | #fff | Output artifacts, files, results |
| detector | #b71c1c | #ef5350 | #fff | Detection, validation, guards |
| gap | #ff6f00 | #ffa726 | #000 | Gaps, warnings, missing items |
| integration | #c62828 | #ef9a9a | #fff | Integration points, external systems |
| terminal | #1a237e | #7986cb | #fff | Start/End/Error terminals |

---

## Diagram Template

````markdown
```mermaid
%%{init: {'flowchart': {'nodeSpacing': 50, 'rankSpacing': 60, 'curve': 'basis'}}}%%
graph TB
    %% CLASS DEFINITIONS %%
    classDef cli fill:#1a237e,stroke:#7986cb,stroke-width:2px,color:#fff;
    classDef stateNode fill:#004d40,stroke:#4db6ac,stroke-width:2px,color:#fff;
    classDef handler fill:#e65100,stroke:#ffb74d,stroke-width:2px,color:#fff;
    classDef phase fill:#6a1b9a,stroke:#ba68c8,stroke-width:2px,color:#fff;
    classDef newComponent fill:#2e7d32,stroke:#81c784,stroke-width:2px,color:#fff;
    classDef output fill:#00695c,stroke:#4db6ac,stroke-width:2px,color:#fff;
    classDef detector fill:#b71c1c,stroke:#ef5350,stroke-width:2px,color:#fff;
    classDef gap fill:#ff6f00,stroke:#ffa726,stroke-width:2px,color:#000;
    classDef terminal fill:#1a237e,stroke:#7986cb,stroke-width:2px,color:#fff;

    %% TERMINAL NODES %%
    START([START])
    END([END])

    %% SUBGRAPHS %%
    subgraph GroupName ["Group Title"]
        direction TB
        Node1["Label Line 1<br/>━━━━━━━━━━<br/>Detail line"]
        Node2["Another Node"]
    end

    %% CONNECTIONS %%
    START --> Node1
    Node1 --> Node2
    Node2 --> END

    %% CLASS ASSIGNMENTS %%
    class Node1,Node2 handler;
    class START,END terminal;
```

**Color Legend:**
| Color | Category | Description |
|-------|----------|-------------|
| Dark Blue | Terminal | Start and end points |
| Orange | Handler | Processing components |
````

---

## Node Shape Reference

```
A([Label])     # Rounded: Start/End terminals
A{Label}       # Diamond: Decision points
A[Label]       # Rectangle: Standard nodes
A[(Label)]     # Cylinder: Database/storage
A[[Label]]     # Subroutine: Subgraph call
A{{Label}}     # Hexagon: Preparation step
```

---

## Multiline Labels

Use `<br/>` for line breaks and `━━━━━━━━━━` as visual separator:

```
Node["Title<br/>━━━━━━━━━━<br/>Description line 1<br/>Description line 2"]
```

---

## Status Symbols

Use symbols to indicate component status:

| Symbol | Meaning |
|--------|---------|
| ★ | New component to implement |
| ● | Existing component with modifications |
| _(none)_ | Existing, unchanged component |

Example:
```
Node["★ NewHandler<br/>━━━━━━━━━━<br/>Proposed feature"]
```

---

## Example: Simple Workflow

```mermaid
%%{init: {'flowchart': {'nodeSpacing': 40, 'rankSpacing': 50}}}%%
flowchart LR
    classDef phase fill:#6a1b9a,stroke:#ba68c8,stroke-width:2px,color:#fff;
    classDef handler fill:#e65100,stroke:#ffb74d,stroke-width:2px,color:#fff;
    classDef terminal fill:#1a237e,stroke:#7986cb,stroke-width:2px,color:#fff;

    START([START])

    subgraph Workflow ["T → I → V Workflow"]
        T["TestCreator (T)<br/>━━━━━━━━━━<br/>Create tests first"]
        I["Implementer (I)<br/>━━━━━━━━━━<br/>Implement code"]
        V["Verifier (V)<br/>━━━━━━━━━━<br/>Validate results"]
    end

    END([END])

    START --> T --> I --> V --> END

    class T,I,V handler;
    class START,END terminal;
```

**Color Legend:**
| Color | Category | Description |
|-------|----------|-------------|
| Dark Blue | Terminal | Start and end points |
| Orange | Handler | Role-based execution nodes |

---

## Example: Complex Architecture

```mermaid
%%{init: {'flowchart': {'nodeSpacing': 50, 'rankSpacing': 60, 'curve': 'basis'}}}%%
graph TB
    classDef cli fill:#1a237e,stroke:#7986cb,stroke-width:2px,color:#fff;
    classDef stateNode fill:#004d40,stroke:#4db6ac,stroke-width:2px,color:#fff;
    classDef handler fill:#e65100,stroke:#ffb74d,stroke-width:2px,color:#fff;
    classDef phase fill:#6a1b9a,stroke:#ba68c8,stroke-width:2px,color:#fff;
    classDef output fill:#00695c,stroke:#4db6ac,stroke-width:2px,color:#fff;

    subgraph CLI_Layer ["CLI Entry Layer"]
        TaskOpt["--task / -t<br/>━━━━━━━━━━<br/>Task description"]
        PathOpt["--project-path<br/>━━━━━━━━━━<br/>Project location"]
    end

    subgraph State_Layer ["State Management"]
        State["GraphState<br/>━━━━━━━━━━<br/>Mutable context<br/>Phase tracking"]
    end

    subgraph Processing ["Processing Pipeline"]
        Init["init_node<br/>━━━━━━━━━━<br/>Initialize state"]
        Handler["MainHandler<br/>━━━━━━━━━━<br/>Process request"]
        Complete["complete_node<br/>━━━━━━━━━━<br/>Finalize output"]
    end

    subgraph Output ["Output Artifacts"]
        Result["result.json<br/>━━━━━━━━━━<br/>Final output"]
    end

    TaskOpt --> State
    PathOpt --> State
    State --> Init
    Init --> Handler
    Handler --> Complete
    Complete --> Result

    class TaskOpt,PathOpt cli;
    class State stateNode;
    class Init,Complete phase;
    class Handler handler;
    class Result output;
```

**Color Legend:**
| Color | Category | Description |
|-------|----------|-------------|
| Dark Blue | CLI | Command-line interface options |
| Teal | State | State management and context |
| Purple | Phase | Control flow and phase nodes |
| Orange | Handler | Processing and business logic |
| Dark Teal | Output | Generated artifacts and results |