diagram-maker

diagram-maker is a skill for Claude Code, Codex from amanning3390/hermeshub. It costs 56 tokens per session (2,760 once invoked), scanned A, original, MIT.

A guide for creating Mermaid diagrams from plain-language requests. Mermaid is a text format for diagrams such as flowcharts, sequence diagrams, and database relationships.

In plain words
What is it for?
Use it to document software architecture, workflows, API interactions, data models, state machines, schedules, and other processes, or to fix a broken Mermaid diagram.
Why use it?
It helps avoid syntax errors that can stop Mermaid diagrams from rendering. It also helps keep complex diagrams readable.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to document software architecture, workflows, API interactions, data models, state machines, schedules, and other processes, or to fix a broken Mermaid diagram.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/amanning3390/hermeshub/diagram-maker
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 amanning3390/hermeshub --skill diagram-maker
Clone the repo
git clone --depth 1 https://github.com/amanning3390/hermeshub

Made for: Claude Code, Codex.

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 diagram-maker

README.md
[![agentmods](https://agentmods.dev/badge/skills/amanning3390/hermeshub/diagram-maker/github.svg)](https://agentmods.dev/skills/amanning3390/hermeshub/diagram-maker)
Your own site
<a href="https://agentmods.dev/skills/amanning3390/hermeshub/diagram-maker"><img src="https://agentmods.dev/badge/skills/amanning3390/hermeshub/diagram-maker/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 diagram-maker

Your own site · 80×15
<a href="https://agentmods.dev/skills/amanning3390/hermeshub/diagram-maker"><img src="https://agentmods.dev/badge/skills/amanning3390/hermeshub/diagram-maker.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,760 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.
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 $0.00056 $0.02760
Opus 5 $0.00028 $0.01380
Sonnet 5 $0.00011 $0.00552
Haiku 4.5 $0.00006 $0.00276

Measured 11d ago against content hash 99c05d9b4853, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

diagram-maker 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 11d 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.

skills/diagram-maker/SKILL.md · 340 lines

How it starts

The opening of the file, as written. The whole thing — 340 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Diagram Maker

Generate production-ready Mermaid diagrams that render on the first try.

When to Use

  • User asks for a diagram, flowchart, or visual representation
  • User wants to document architecture, workflows, or processes
  • User needs sequence diagrams for API interactions
  • User asks for ER diagrams, class diagrams, or state machines
  • User wants Gantt charts, pie charts, or timeline diagrams
  • User has a broken Mermaid diagram that needs fixing

Why This Exists

LLMs frequently produce Mermaid diagrams that fail to parse. The most common failures are:

  1. Unquoted labels with special characters (parentheses, commas, arrows)
  2. HTML tags in node text (<br/> outside quotes, <b> tags)
  3. Reserved word collisions (end, graph, style used as node IDs)
  4. Mismatched brackets[], (), {} not properly paired
  5. Invalid arrow syntax — mixing up -->, ==>, -.->, -->
  6. Subgraph nesting errors — missing end keywords or improper direction
  7. Semicolons and whitespace — trailing semicolons that break parsers
  8. Overly complex single diagrams — 50+ nodes that become unreadable

This skill eliminates these failures with strict syntax rules.

Procedure

  1. Identify the diagram type from the user's request (see Type Selection below)
  2. Plan the structure — list nodes and relationships before writing syntax
  3. Write the diagram following the Syntax Rules below
  4. Self-validate — check every node label, arrow, and bracket
  5. Output the diagram in a fenced mermaid code block
  6. If the diagram exceeds 30 nodes, split into multiple focused diagrams

Type Selection

User Intent Diagram Type Declaration
Process, workflow, decision tree Flowchart flowchart TD or flowchart LR
API calls, request/response Sequence sequenceDiagram
Object relationships, inheritance Class classDiagram
Database tables, relationships ER erDiagram
State transitions, lifecycles State stateDiagram-v2
Project timeline, milestones Gantt gantt
Proportions, percentages Pie pie
Git branching Git Graph gitGraph
User journey Journey journey
System context C4 C4Context
Nested hierarchy Mindmap mindmap
Release timeline Timeline timeline

Read the full file on GitHub · 340 lines

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. 11d ago First seen · 340 lines · 56 tokens per session scan A 99c05d9b4853

Subscribe to this mod's changes

diagram-maker is a skill published in the GitHub repository amanning3390/hermeshub (36 stars, last pushed 2mo ago), licensed MIT. It adds 56 tokens to every session and 2,760 once invoked, about $0.0003 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.

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