excalidraw

excalidraw is a skill for Claude Code, Codex from math-inc/OpenGauss. It costs 58 tokens per session (2,256 once invoked), scanned A, a copy of excalidraw, MIT.

A tool for creating editable hand-drawn diagrams in Excalidraw's JSON file format. Excalidraw is a browser-based diagram editor that can open these files.

In plain words
What is it for?
Creating architecture diagrams, process flowcharts, sequence diagrams, and concept maps, with optional upload for a shareable Excalidraw link.
Why use it?
It lets coding agents produce architecture diagrams, flowcharts, and other visuals as files that people can open and edit without special rendering software or an account.

Skill for Claude CodeCodex

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

Good fit Creating architecture diagrams, process flowcharts, sequence diagrams, and concept maps, with optional upload for a shareable Excalidraw link.

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Install with agentmods
npx agentmods add skills/math-inc/opengauss/excalidraw
About the project

OpenGauss is a project-scoped Lean workflow orchestrator that gives coding agents a command-line interface for managing formal proof and formalization tasks. It is used with Lean projects to coordinate agents, tooling, backend sessions, and workflows supplied by lean4-skills. The catalogue add-ons operate these Gauss-native workflows.

math-inc/OpenGauss · 1,260 stars · on GitHub

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 math-inc/OpenGauss --skill excalidraw
Clone the repo
git clone --depth 1 https://github.com/math-inc/OpenGauss

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 excalidraw

README.md
[![agentmods](https://agentmods.dev/badge/skills/math-inc/opengauss/excalidraw.svg)](https://agentmods.dev/skills/math-inc/opengauss/excalidraw)
Your own site
<a href="https://agentmods.dev/skills/math-inc/opengauss/excalidraw"><img src="https://agentmods.dev/badge/skills/math-inc/opengauss/excalidraw.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,256 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 92% copy Near-identical to another mod 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 $0.00058 $0.02256
Opus 5 $0.00029 $0.01128
Sonnet 5 $0.00012 $0.00451
Haiku 4.5 $0.00006 $0.00226

Measured 8d ago against content hash 2fddd21f51dc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

excalidraw 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/upload.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.

Origin

This is a copy

92% identical to excalidraw — 17 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.

skills/creative/excalidraw/SKILL.md · 195 lines

How it starts

The opening of the file, as written. The whole thing — 195 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Excalidraw Diagram Skill

Create diagrams by writing standard Excalidraw element JSON and saving as .excalidraw files. These files can be drag-and-dropped onto excalidraw.com for viewing and editing. No accounts, no API keys, no rendering libraries -- just JSON.

Workflow

  1. Load this skill (you already did)
  2. Write the elements JSON -- an array of Excalidraw element objects
  3. Save the file using write_file to create a .excalidraw file
  4. Optionally upload for a shareable link using scripts/upload.py via terminal

Saving a Diagram

Wrap your elements array in the standard .excalidraw envelope and save with write_file:

{
  "type": "excalidraw",
  "version": 2,
  "source": "gauss-agent",
  "elements": [ ...your elements array here... ],
  "appState": {
    "viewBackgroundColor": "#ffffff"
  }
}

Save to any path, e.g. ~/diagrams/my_diagram.excalidraw.

Uploading for a Shareable Link

Run the upload script (located in this skill's scripts/ directory) via terminal:

python skills/diagramming/excalidraw/scripts/upload.py ~/diagrams/my_diagram.excalidraw

This uploads to excalidraw.com (no account needed) and prints a shareable URL. Requires the cryptography pip package (pip install cryptography).


Element Format Reference

Required Fields (all elements)

type, id (unique string), x, y, width, height

Defaults (skip these -- they're applied automatically)

  • strokeColor: "#1e1e1e"
  • backgroundColor: "transparent"
  • fillStyle: "solid"
  • strokeWidth: 2
  • roughness: 1 (hand-drawn look)
  • opacity: 100

Canvas background is white.

Element Types

Rectangle:

{ "type": "rectangle", "id": "r1", "x": 100, "y": 100, "width": 200, "height": 100 }
  • roundness: { "type": 3 } for rounded corners
  • backgroundColor: "#a5d8ff", fillStyle: "solid" for filled

Ellipse:

{ "type": "ellipse", "id": "e1", "x": 100, "y": 100, "width": 150, "height": 150 }

Read the full file on GitHub · 195 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 · 195 lines · 58 tokens per session scan A 2fddd21f51dc

Subscribe to this mod's changes

excalidraw is a skill published in the GitHub repository math-inc/OpenGauss (1,260 stars, last pushed 5mo ago), licensed MIT. It adds 58 tokens to every session and 2,256 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to excalidraw, differing in 17 lines, and is treated as a copy.

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