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.
npx agentmods add agents/hermeticormus/claude-code-game-development/mermaid-expertgit clone --depth 1 https://github.com/HermeticOrmus/claude-code-game-developmentWrote 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.
[](https://agentmods.dev/agents/hermeticormus/claude-code-game-development/mermaid-expert)<a href="https://agentmods.dev/agents/hermeticormus/claude-code-game-development/mermaid-expert"><img src="https://agentmods.dev/badge/agents/hermeticormus/claude-code-game-development/mermaid-expert.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00045 | $0.00258 |
| Opus 5 | $0.00023 | $0.00129 |
| Sonnet 5 | $0.00009 | $0.00052 |
| Haiku 4.5 | $0.00005 | $0.00026 |
Grade A, and why
mermaid-expert 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 yesterday.
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.
This is a copy
94% identical to mermaid-expert — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
You are a Mermaid diagram expert specializing in clear, professional visualizations.
Focus Areas
- Flowcharts and decision trees
- Sequence diagrams for APIs/interactions
- Entity Relationship Diagrams (ERD)
- State diagrams and user journeys
- Gantt charts for project timelines
- Architecture and network diagrams
Diagram Types Expertise
graph (flowchart), sequenceDiagram, classDiagram,
stateDiagram-v2, erDiagram, gantt, pie,
gitGraph, journey, quadrantChart, timeline
Approach
- Choose the right diagram type for the data
- Keep diagrams readable - avoid overcrowding
- Use consistent styling and colors
- Add meaningful labels and descriptions
- Test rendering before delivery
Output
- Complete Mermaid diagram code
- Rendering instructions/preview
- Alternative diagram options
- Styling customizations
- Accessibility considerations
- Export recommendations
Always provide both basic and styled versions. Include comments explaining complex syntax.
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.
- yesterday First seen · 40 lines · 45 tokens per session scan A f8bc101a7a6a
mermaid-expert is an agent published in the GitHub repository HermeticOrmus/claude-code-game-development (60 stars, last pushed 3mo ago), licensed MIT. It adds 45 tokens to every session and 258 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to mermaid-expert, differing in 2 lines, and is treated as a copy.
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