diagram-studio

diagram-studio is a skill for Claude Code from ddtcorex/maestro-skills. It costs 38 tokens per session (1,971 once invoked), scanned A, original, MIT.

A guide for creating technical diagrams in Mermaid, a text format supported by tools such as GitHub. It covers diagrams for system parts, message flows, data relationships, classes, and state changes.

In plain words
What is it for?
Use it for architecture, sequence, class, entity-relationship, or state diagrams in documentation and presentation material.
Why use it?
It makes complex software structure and behavior easier to understand and helps check diagrams against the codebase as the system changes.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the maestro-skills plugin — 31 skills shipped together

Good fit Use it for architecture, sequence, class, entity-relationship, or state diagrams in documentation and presentation material.

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

Made for: Claude Code.

Or install maestro-skills, the plugin that ships this one along with the rest of its 31 skills.

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-studio

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/ddtcorex/maestro-skills/diagram-studio"><img src="https://agentmods.dev/badge/skills/ddtcorex/maestro-skills/diagram-studio.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,971 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 $0.00038 $0.01971
Opus 5 $0.00019 $0.00986
Sonnet 5 $0.00008 $0.00394
Haiku 4.5 $0.00004 $0.00197

Measured 12d ago against content hash 0ae03c8cfd60, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

diagram-studio 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 12d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/verify-mermaid.mjs, tests/pressure.test.mjs, tests/verify-cli.test.mjs), 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.

skills/diagram-studio/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Diagram Studio

Hybrid Mermaid + editorial HTML for architecture, sequence, class, ER, and state diagrams.

When to Use

Use when the reader learns more from a visual than from a paragraph or table. Ideal for system architecture, message flows over time, entity relationships, class structures, and state transitions with guards.

Don't use for simple lists, single before/after comparisons, or a one-sentence relationship that a table can express — use a table instead.

Selection

Choose the Mermaid type by the semantic pattern, not by habit. See references/cheatsheet.md for minimal examples.

If showing… Use Reference
Components + connections flowchart cheatsheet.md#flowchart
Messages over time sequenceDiagram cheatsheet.md#sequence
States + guards stateDiagram cheatsheet.md#state
Entities + fields erDiagram cheatsheet.md#er
Classes + ops classDiagram cheatsheet.md#class

Full 39-type editorial taxonomy from cathrynlavery/diagram-design is mapped to these 5 Mermaid types — start with the table above before inventing a new form.

GitHub-compatible Mermaid style: use flowchart TB or flowchart LR (never legacy graph), add classDef tokens from references/style-guide.md, and use linkStyle/style sparingly for the focal path.

flowchart TB
  A["Client"] --> B["Cordis"]
  classDef focal fill:#eb6c36,stroke:#2d3142,color:#fff
  class A focal

Editorial Discipline (from diagram-design)

Extracted from cathrynlavery/diagram-design — see references/diagram-design-learnings.md:

  • Density 4/10 — generous whitespace, no wall of boxes. Every node must earn its place.
  • >9 nodes → split into overview + detail diagrams rather than cramming.
  • Accent 1-2 max — use classDef focal fill:#eb6c36,stroke:#2d3142 for the single hot path; all other nodes stay paper/muted. No shadows (shadow:false), rx:6 max, mono only for ports/URLs.
  • Confirm before drawing — state type, size preset (85%/100%), what will be cut due to budget and wait for redirect if the user is reachable. Never assume the diagram scope.

Read the full file on GitHub · 97 lines

Files

What ships with it

7 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. 12d ago First seen · 97 lines · 38 tokens per session scan A 0ae03c8cfd60

Subscribe to this mod's changes

diagram-studio is a skill published in the GitHub repository ddtcorex/maestro-skills (4 stars, last pushed yesterday), licensed MIT. It adds 38 tokens to every session and 1,971 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 2026-08-31.

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