mermaid-graph-writer

mermaid-graph-writer is a skill for Claude Code from curiositech/some_claude_skills. It costs 111 tokens per session (2,427 once invoked), scanned A, original, MIT.

A guide for creating Mermaid diagrams from a description or data. Mermaid is a text-based diagram format that can represent flowcharts, sequences, states, data relationships, timelines, and more.

In plain words
What is it for?
Creating architecture diagrams, flowcharts, sequence diagrams, state machines, entity-relationship models, timelines, mind maps, and Gantt charts.
Why use it?
It helps choose an appropriate diagram type and produce readable, valid Mermaid text. It is for writing diagrams, not exporting them to image or PDF files.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the mermaid-graph-writer plugin — 1 skill shipped together

Good fit Creating architecture diagrams, flowcharts, sequence diagrams, state machines, entity-relationship models, timelines, mind maps, and Gantt charts.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/curiositech/some_claude_skills/mermaid-graph-writer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add curiositech/some_claude_skills --skill mermaid-graph-writer
Clone the repo
git clone --depth 1 https://github.com/curiositech/some_claude_skills

Made for: Claude Code.

Or install mermaid-graph-writer, the plugin that ships this one along with the rest of its 1 skill.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for mermaid-graph-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/curiositech/some_claude_skills/mermaid-graph-writer/github.svg)](https://agentmods.dev/skills/curiositech/some_claude_skills/mermaid-graph-writer)
Your own site
<a href="https://agentmods.dev/skills/curiositech/some_claude_skills/mermaid-graph-writer"><img src="https://agentmods.dev/badge/skills/curiositech/some_claude_skills/mermaid-graph-writer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for mermaid-graph-writer

Your own site · 80×15
<a href="https://agentmods.dev/skills/curiositech/some_claude_skills/mermaid-graph-writer"><img src="https://agentmods.dev/badge/skills/curiositech/some_claude_skills/mermaid-graph-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 111 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,427 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00111 $0.02427
Opus 5 $0.00056 $0.01213
Sonnet 5 $0.00022 $0.00485
Haiku 4.5 $0.00011 $0.00243

Measured 8d ago against content hash 7228e3d8172b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

mermaid-graph-writer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate_mermaid.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/mermaid-graph-writer/SKILL.md · 297 lines

How it starts

The opening of the file, as written. The whole thing — 297 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mermaid Graph Writer

Writes precise, well-structured Mermaid diagrams. Selects the optimal diagram type for the content, uses correct syntax, and produces diagrams that are readable by both humans (rendered) and agents (text DSL).


When to Use

Use for:

  • Creating any Mermaid diagram from a description or data
  • Choosing the right diagram type for a visualization need
  • Refactoring prose decision trees into Mermaid flowcharts
  • Modeling system architectures, protocols, state machines, data models
  • Encoding temporal knowledge as timeline diagrams

NOT for:

  • Rendering/exporting Mermaid to PNG/SVG/PDF (use mermaid-graph-renderer)
  • ASCII art or Unicode box-drawing (use diagramming-expert)
  • GUI-based design tools (Figma, etc.)

Diagram Type Selection

flowchart TD
  A{What are you modeling?} -->|Branching logic| B[flowchart]
  A -->|Request/response over time| C[sequenceDiagram]
  A -->|States and transitions| D[stateDiagram-v2]
  A -->|Entities and relationships| E[erDiagram]
  A -->|Chronological evolution| F[timeline]
  A -->|Concept hierarchy| G[mindmap]
  A -->|Time-sequenced tasks| H[gantt]
  A -->|Proportions| I[pie]
  A -->|2-axis comparison| J[quadrantChart]
  A -->|Branch/merge history| K[gitGraph]
  A -->|Type hierarchy / OO| L[classDiagram]
  A -->|User experience steps| M[journey]
  A -->|Quantity flows| N[sankey-beta]
  A -->|Numeric data| O[xychart-beta]
  A -->|System components| P[block-beta]
  A -->|Infrastructure| Q[architecture-beta]
  A -->|Task board| R[kanban]
  A -->|Requirements traceability| S[requirementDiagram]
  A -->|System context / containers| T[C4Context]
  A -->|Protocol packets / headers| U[packet-beta]
  A -->|Multi-axis comparison| V[radar]
  A -->|Hierarchical proportions| W[treemap]
  A -->|Code-style sequences| X[zenuml]

Quick Reference

Content Type Direction
Decision tree / process flowchart TD Top-down for decisions, LR for processes
API protocol / agent comms sequenceDiagram Always vertical (implicit)
Lifecycle / status machine stateDiagram-v2 Automatic layout
Database / data model erDiagram Automatic layout
"What changed when" timeline Horizontal chronological
Taxonomy / brainstorm mindmap Radial from root
Project schedule gantt Horizontal timeline
Category proportions pie Circular
Effort vs. impact quadrantChart 2D scatter
Git branching strategy gitGraph Horizontal
Class/interface hierarchy classDiagram Automatic
User flow with satisfaction journey Horizontal sections
Flow quantities between categories sankey-beta Left-to-right flow
Bar/line charts xychart-beta Standard axes
System block layout block-beta Grid-based
Cloud/infra topology architecture-beta Grouped services
Task status columns kanban Column-based
Requirements traceability requirementDiagram Automatic layout
System context / containers C4Context / C4Container Layered (5 sub-types)
Protocol packets / headers packet-beta Horizontal bit layout
Multi-axis scoring radar Radial axes
Hierarchical proportions treemap Nested rectangles
Code-style sequences zenuml Vertical (plugin)

Read the full file on GitHub · 297 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 297 lines · 111 tokens per session scan A 7228e3d8172b

Subscribe to this mod's changes

mermaid-graph-writer is a skill published in the GitHub repository curiositech/some_claude_skills (221 stars, last pushed 5d ago), licensed MIT. It adds 111 tokens to every session and 2,427 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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