excalidraw

excalidraw is a skill for Claude Code, Codex from eigent-ai/agent-skills. It costs 45 tokens per session (1,969 once invoked), scanned A, original, Apache-2.0.

A tool for creating Excalidraw architecture diagrams from a codebase. Excalidraw is a diagram editor that saves drawings as editable files.

In plain words
What is it for?
Use it to generate system diagrams, visualize codebase structure, and save architecture diagrams as .excalidraw files.
Why use it?
It turns the structure of a software project into a visual map, making services, databases, APIs, and data flows easier to understand.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code.

Good fit Use it to generate system diagrams, visualize codebase structure, and save architecture diagrams as .excalidraw files.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/eigent-ai/agent-skills/excalidraw
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 eigent-ai/agent-skills --skill excalidraw
Clone the repo
git clone --depth 1 https://github.com/eigent-ai/agent-skills

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/eigent-ai/agent-skills/excalidraw.svg)](https://agentmods.dev/skills/eigent-ai/agent-skills/excalidraw)
Your own site
<a href="https://agentmods.dev/skills/eigent-ai/agent-skills/excalidraw"><img src="https://agentmods.dev/badge/skills/eigent-ai/agent-skills/excalidraw.svg" alt="Measured on agentmods" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,969 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 $0.00045 $0.01969
Opus 5 $0.00023 $0.00984
Sonnet 5 $0.00009 $0.00394
Haiku 4.5 $0.00005 $0.00197

Measured 8d ago against content hash 4e5e0235b446, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, 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.

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/web-and-frontend-development/excalidraw/SKILL.md · 267 lines

How it starts

The opening of the file, as written. The whole thing — 267 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Excalidraw Diagram Generator

Generate architecture diagrams as .excalidraw files directly from codebase analysis.


Quick Start

User just asks:

"Generate an architecture diagram for this project"
"Create an excalidraw diagram of the system"
"Visualize this codebase as an excalidraw file"

Claude Code will:

  1. Analyze the codebase (any language/framework)
  2. Identify components, services, databases, APIs
  3. Map relationships and data flows
  4. Generate valid .excalidraw JSON with dynamic IDs and labels

No prerequisites: Works without existing diagrams, Terraform, or specific file types.


Critical Rules

1. NEVER Use Diamond Shapes

Diamond arrow connections are broken in raw Excalidraw JSON. Use styled rectangles instead:

Semantic Meaning Rectangle Style
Orchestrator/Hub Coral (#ffa8a8/#c92a2a) + strokeWidth: 3
Decision Point Orange (#ffd8a8/#e8590c) + dashed stroke

2. Labels Require TWO Elements

The label property does NOT work in raw JSON. Every labeled shape needs:

// 1. Shape with boundElements reference
{
  "id": "my-box",
  "type": "rectangle",
  "boundElements": [{ "type": "text", "id": "my-box-text" }]
}

// 2. Separate text element with containerId
{
  "id": "my-box-text",
  "type": "text",
  "containerId": "my-box",
  "text": "My Label"
}

3. Elbow Arrows Need Three Properties

For 90-degree corners (not curved):

{
  "type": "arrow",
  "roughness": 0,        // Clean lines
  "roundness": null,     // Sharp corners
  "elbowed": true        // 90-degree mode
}

4. Arrow Edge Calculations

Arrows must start/end at shape edges, not centers:

Edge Formula
Top (x + width/2, y)
Bottom (x + width/2, y + height)
Left (x, y + height/2)
Right (x + width, y + height/2)

Detailed arrow routing: See references/arrows.md


Element Types

Type Use For
rectangle Services, databases, containers, orchestrators
ellipse Users, external systems, start/end points
text Labels inside shapes, titles, annotations
arrow Data flow, connections, dependencies
line Grouping boundaries, separators

Read the full file on GitHub · 267 lines

Files

What ships with it

5 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 · 267 lines · 45 tokens per session scan A 4e5e0235b446

Subscribe to this mod's changes

excalidraw is a skill published in the GitHub repository eigent-ai/agent-skills (19 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 45 tokens to every session and 1,969 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.

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