mermaid-expert

An assistant for creating Mermaid diagrams from text. Mermaid is a diagram language that can describe flows, API interactions, database relationships, system architecture, and timelines.

In plain words
What is it for?
Use it to create flowcharts, sequence diagrams, entity-relationship diagrams, state diagrams, architecture diagrams, Gantt charts, and other Mermaid visualisations.
Why use it?
It helps turn complicated processes or system structures into diagrams that are easier to read and maintain as code.

Agent for Claude Code

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.

agentmods
npx agentmods add agents/echovic/blade-code/mermaid-expert
Clone the repo
git clone --depth 1 https://github.com/echoVic/blade-code

Made for: Claude Code.

Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 258 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00045 $0.00258
Opus 5 $0.00023 $0.00129
Sonnet 5 $0.00009 $0.00052
Haiku 4.5 $0.00005 $0.00026

Measured 2d ago against content hash ac5a8c104f63, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 2d ago.

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.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

.claude/agents/mermaid-expert.md · 40 lines

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

  1. Choose the right diagram type for the data
  2. Keep diagrams readable - avoid overcrowding
  3. Use consistent styling and colors
  4. Add meaningful labels and descriptions
  5. 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.

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. 2d ago First seen · 40 lines · 45 tokens per session scan A ac5a8c104f63

Subscribe to this mod's changes

mermaid-expert is an agent published in the GitHub repository echoVic/blade-code (177 stars, last pushed 2d 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.