workflowstacks
claude-skill

penecho: Visual AI Canvas for Handwriting, Math & Diagrams

Turn sketches, equations and spatial ideas into AI‑enhanced insights on a shared canvas. Ideal for founders building educational or visual‑thinking products. 2.4k+ GitHub stars.
2,434 stars317 forksJavaScriptGuide quality 9/10 · reviewed Oct 4Updated 9/27/2026100% free · open source
What it does

Penecho allows users to collaborate with AI on a shared canvas, enabling handwriting, equations, diagrams, and spatial reasoning beyond traditional chat box interactions.

When to use it
  • •When creating complex diagrams or equations that require spatial reasoning and collaboration
  • •When needing to annotate or mark up images or documents with handwritten notes
  • •When developing educational content that requires interactive, visual explanations
Ready-to-paste prompt
Open the Penecho canvas and draw a simple equation, such as '2x + 5 = 11', to demonstrate the AI-powered equation recognition and solution capabilities
Heads up: Ensure that your development environment meets the prerequisites specified in the README, including the required version of Node.js and any necessary dependencies, to avoid compatibility issues
Saves to your device
Use with Claude
New

Skip the builder — one click puts this in Claude, Cursor, Antigravity and more.

⚡ Runs out of the box

A prompt/skill package — nothing to install beyond adding it to your AI tool.

Try it instantly — no install
Claude Code
mkdir -p ~/.claude/skills/penecho && curl -fsSL https://workflowstacks.com/api/skills/penecho/claude-skill -o ~/.claude/skills/penecho/SKILL.md
Open in another AI app

Opens the app with this repo with the prompt ready to go — no copy-paste needed.

Connect the whole catalog (MCP)
claude mcp add --transport http workflowstacks https://workflowstacks.com/api/mcp

Adds a WorkflowStacks connector to Claude Code: search and load any skill here by chatting.

How penecho: Visual AI Canvas for Handwriting, Math & Diagrams works
Codeflow
Free to inspect

Penecho: Visual AI Canvas for Handwriting, Math & Diagrams is a very large JavaScript project (~161k lines across 392 code files, plus 282 test files). You install it into your AI tool with one command; there is nothing to run yourself. Last commit this month, AGPL-3.0 license, has a test suite.

Size
Very large codebase
~161k lines · 392 code files · days to read — use, don't read
Setup
Install as a skill / plugin
Add it to Claude Code (or your AI tool) with one command — 2 skills inside. Nothing to run yourself.
Runs on
Inside your AI tool
Helper scripts use Node.js
JavaScript 90%CSS 7%HTML 2%TypeScript 1%
Where to start reading
  1. 1
    README.md
    Start here — what it does and how to install it
  2. 2
    cli.js
    Where the program starts running
  3. 3
    src/cli/main.js
    Inside src/ — the main logic begins here
What's in each folder
src/Core code — the actual logic171 files
skills/Prompts, skills & agent definitions1 files
integrations/Sub-packages / plugins14 files
docs/Documentation79 files
scripts/Helper scripts186 files
desktop/Folder16 files
tools/Helper scripts8 files
testcase/Folder4 files
READMEHas testsDocumentedCI checksAGPL-3.0 licenseUpdated this month
Quick Actions
Details
Creator
penecho
Language
JavaScript
Category
claude-skill
Published
7/14/2026

Are you the creator of this tool? and earn 85% of every sale.

Show it off in your README:

Featured on WorkflowStacks
[![Featured on WorkflowStacks](https://workflowstacks.com/api/badge/penecho.svg)](https://workflowstacks.com/skills/penecho?utm_source=github&utm_medium=badge)
🔥 Hot this week, in your inbox
Skills like this, every Monday.

The five fastest-growing open-source AI skills, ranked by GitHub star growth. One email a week, unsubscribe anytime.

Do this with a working workflow

Pages we wrote and tested that put a skill like this to work — importable n8n templates, outcome guides and Claude Desktop configs.

MCP config

Sequential Thinking MCP config

Give Claude a structured, step-by-step reasoning scratchpad.

MCP config

GitHub MCP config

Search repos, read code, open issues and PRs from Claude.

Related skills

More claude-skill tools founders pair with this one.

claude-skill★ 252,432
Hermes-Agent: AI Growth
Scale with a versatile AI agent. For startup founders using Python and AI.
claude-skill★ 187,517
AutoGPT: Build Autonomous AI Agents Faster
AutoGPT lets founders launch self‑directing AI agents without deep ML work, so you can concentrate on product and growth. Ideal for Python‑savvy teams. 188k+ GitHub stars
claude-skill★ 147,571
langchain
The agent engineering platform.
claude-skill★ 117
ForgeDock: Automated Dev Pipeline
Automate dev workflows with ForgeDock. For founders using Claude Code.
claude-skill★ 623
avibe: AI Partner on Your Machine
Run AI tools locally with avibe. For founders needing local AI control.
claude-skill★ 2,108
meridian: Unlock Claude Max
Enable Claude Max in third-party tools with meridian, a proxy for startup founders, backed by 1.7k+ GitHub stars.