diagram-generator – Design & UI skill for AI agents

Bundled upstream support

Supporting files are included at skill-relative paths. See [UPSTREAM-NOTICE.md](UPSTREAM-NOTICE.md) for their pinned sources, licenses, hashes, and import changes.

Diagram Generator

When to Use

• Turning textual analysis into Mermaid/Graphviz/PlantUML visuals.
• Producing attack-path or architecture diagrams for reports.

Purpose

Create clear, editable diagrams from messy or structured inputs. Prefer text-based diagram source first so the result can be reviewed, versioned, and refined. Render to files only when the user asks for an image/PDF or when a downloadable artifact would materially help.

Default workflow

1. Identify the user's intent, audience, and source material.

2. Choose the diagram family and language using the decision table below.

3. Normalize entities, relationships, labels, states, branches, and time/order information before writing diagram code.

4. Generate concise, readable diagram source.

5. Validate the syntax mentally and, when creating files, run scripts/render_diagram.py.

6. Return the diagram source plus a short note about assumptions. When files are generated, include links to the output files.

Do not over-ask for clarification. If the request is underspecified, make reasonable assumptions and label them briefly.

Diagram language decision table

Use Mermaid unless another language is clearly better.

| User wants | Prefer | Why |

|---|---|---|

| process flow, decision tree, simple swimlane | Mermaid flowchart | readable and easy to paste into Markdown |

| sequence of system/user interactions | Mermaid sequenceDiagram or PlantUML sequence | Mermaid for docs; PlantUML for UML formality |

| lifecycle, state machine, transitions | Mermaid stateDiagram-v2 or PlantUML state | compact transition syntax |

| database schema, entities, relationships | Mermaid erDiagram | portable ER notation |

| class/interface/object model | Mermaid classDiagram or PlantUML class | Mermaid for docs; PlantUML for detailed UML |

| project schedule | Mermaid gantt | concise timeline syntax |

| hierarchy, ideas, notes | Mermaid mindmap | good default for idea maps |

| customer/product journey | Mermaid journey | built-in journey notation |

| git history | Mermaid gitGraph | built-in git notation |

| dependency graph, package graph, large network | Graphviz DOT | better layout engines for dense graphs |

| architecture with layers, clusters, boundaries | Mermaid flowchart with subgraphs, Graphviz clusters, or PlantUML C4-style | choose based on requested fidelity |

| weighted flow/sankey-like relationship | Mermaid sankey-beta when supported, otherwise SVG or Graphviz | Mermaid support may vary by renderer |

| custom visual where source languages fit poorly | SVG | precise control over layout and styling |

Output policy

• Always provide editable source unless the user explicitly asks only for an image.
• Default to a single best diagram. Offer alternatives only when genuinely useful.
• Prefer stable, simple syntax over fancy features that may not render in older Mermaid/PlantUML versions.
• Use short labels. Split long text into notes outside the diagram when needed.
• Avoid ambiguous node IDs. Use ASCII IDs and human-readable labels.
• Preserve user terminology, but standardize capitalization within a diagram.
• For technical diagrams, include boundaries such as client, service, database, queue, external API, and operator/user when they are implied.
• For business-process diagrams, distinguish happy path, decision points, failures, retries, and manual steps when present.
• For diagrams created from uncertain text, include an Assumptions section after the code.

Mermaid generation rules

Consult references/diagram-patterns.md for compact templates.

General Mermaid rules:

• Start with the correct diagram directive, for example flowchart TD, sequenceDiagram, erDiagram, gantt, mindmap, or journey.
• For flowcharts, use flowchart TD unless the user asks for left-to-right; use flowchart LR for architecture and pipelines.
• Use subgraphs for swimlanes or architecture layers. Name subgraphs with readable labels.
• Keep node IDs stable and ASCII-only, for example ingest_service[Ingest Service].
• Quote labels that contain punctuation likely to confuse the parser.
• Use decision diamonds for branching: decision{Condition?}.
• Use consistent edge labels: -- yes -->, -- no -->, -. async .->, or == critical ==> only when meaningful.
• In sequence diagrams, declare participants before messages. Use actor for humans and participant for systems.
• Use alt/else/end, opt/end, loop/end, and par/and/end blocks for conditional, optional, repeated, and parallel flows.

Graphviz DOT generation rules

Use Graphviz for large, dense, or layout-sensitive relationship diagrams.

• Prefer digraph G for directed relationships and graph G for undirected networks.
• Set layout-friendly graph attributes at the top: rankdir=LR, nodesep, ranksep, and splines=true when helpful.
• Use subgraph cluster_name for boundaries and subsystems.
• Use plain labels and restrained styling.
• Use edge labels only when they add meaning.
• For many nodes, group by domain with clusters and avoid crossing-heavy all-to-all edges.

PlantUML generation rules

Use PlantUML when the user asks for UML or needs formal UML notation.

• Wrap diagrams with @startuml and @enduml.
• Use actor, participant, database, queue, collections, or component stereotypes when useful.
• Use package, rectangle, or node for architecture boundaries.
• For class diagrams, include only important fields/methods unless the user asks for exhaustive detail.
• For activity diagrams, use clear start/end markers and explicit branch labels.

SVG generation rules

Use SVG only when text diagram languages cannot express the requested visual reliably.

• Keep SVG simple, accessible, and editable.
• Include <title> and meaningful text labels.
• Prefer rectangles, lines, arrows, and groups over complex paths.
• Do not embed external fonts or remote images.

Rendering files

When the user asks for PNG/SVG/PDF, create a source file and run:

python "<SKILL_ROOT>/diagram-generator/scripts/render_diagram.py" input.mmd --format svg --out output.svg
python "<SKILL_ROOT>/diagram-generator/scripts/render_diagram.py" input.dot --format png --out output.png
python "<SKILL_ROOT>/diagram-generator/scripts/render_diagram.py" input.puml --format svg --out output.svg

> <SKILL_ROOT> 是本包 skills/ 目录的实际路径，AI 应自动检测。

The renderer is intentionally dependency-tolerant. It tries common local tools and reports actionable installation hints if a renderer is unavailable. Do not claim an image was rendered unless the script completed successfully and the output file exists.

Only render reviewed diagram sources. The helper invokes locally installed renderers (including PlantUML) and writes the selected output path, and rejects an existing output path; inspect the source and choose a fresh output path whose extension matches --format.

Validation checklist

Before finalizing:

• The diagram type matches the user's task.
• The source is syntactically plausible for the chosen language.
• Labels are short enough to fit.
• Edges and message order reflect the input accurately.
• Assumptions are called out when the input was incomplete.
• For generated files, the output exists and opens or has nonzero size.

Common response template

Use this structure for most diagram answers:

下面是可编辑的 [language] 版本：

[source]

Assumptions:
- [only if needed]

Rendered file: [link] [only if generated]

For English user requests, respond in English. For Chinese user requests, respond in Chinese unless they ask otherwise.

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按需自举（On-Demand Bootstrap）

自动化能力边界

| 工具 | 可自动安装 | 安装方式 | 说明 |

|------|-----------|---------|------|

| Mermaid CLI (mmdc) | ✓ | npm install -g @mermaid-js/mermaid-cli | 渲染 Mermaid 为 PNG/SVG |

| Graphviz (dot) | ✗ | 手动安装 | https://graphviz.org/download/ |

| PlantUML | ✗ | 需要 Java + plantuml.jar | https://plantuml.com/download |

| Python (render script) | ✓ | 已在 bootstrap 中 | scripts/render_diagram.py 依赖 |

说明

本 skill 主要输出文本格式的图表源码（Mermaid/DOT/PlantUML），不一定需要本地渲染工具。只有当用户明确要求生成 PNG/SVG/PDF 文件时才需要对应的渲染器。

如果渲染器不可用，scripts/render_diagram.py 会输出安装提示并以非零状态退出；此时只能交付源码，不能声称已渲染。

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路由上下文

上游入口: skills/SKILL.md（总控）、routing.md

触发条件: 用户说"画图"、"流程图"、"架构图"、"攻击路径图"、"时序图"、"Mermaid"、"Graphviz"、"PlantUML"

下游出口:

• 生成的图表可嵌入 docs-generator/ 的报告中
• 攻击路径图可配合 pentest-tools/ 的渗透报告

同级关联模块: docs-generator/（报告中嵌入图表）

任务完成自检（声称完成前 MUST 通过）

• [ ] 我是否执行了工作流中的每一步（而不是只阅读）？
• [ ] 我是否基于 tool-index 使用了真实工具路径？
• [ ] 我是否产出了可复现证据（命令/脚本/截图/报告）？
• [ ] 我是否完成并回写了 RULES 要求的 Checklist 项？

Limitations

• Complex auto-layouts may need manual adjustment in the target tool.
• Rendering fidelity depends on the available diagram CLI/render

… (full content is in the download package)