---
title: "🛠️ After CoScreen Shut Down, the Original Team Built an Open-Source Petal, This Time No One Can Shut It Down | Open Source Weekly"
description: "After Datadog shut down CoScreen, the original four-person team rebuilt it as the open-source Petal, hitting 220 points on Hacker News right at launch. This episode also covers BetterWispr, a dictation tool that likewise scored 220 points and 127 comments, plus anatomy, which hit 14k stars in 30 days and lets AI draw machine diagrams to explain technical concepts, how to use it, I'll tell you in a moment."
canonical_url: "https://blog.markkulab.net/en/open-source-weekly/open-source-weekly-2026-10-17"
author: "Mark Ku"
author_url: "https://blog.markkulab.net/en/author/mark-ku"
site: "Mark Ku's Tech Notes"
date_published: "2026-10-17T02:00:00.000Z"
category: "Open Source Weekly"
tags: ["open-source", "podcast", "開源工具", "開源", "Petal", "CoScreen", "BetterWispr", "anatomy", "ClaudeCode", "螢幕分享", "語音聽寫"]
language: "en"
license: "CC BY 4.0"
license_url: "https://creativecommons.org/licenses/by/4.0/"
attribution: "when reusing or quoting, credit the author and link back to the original"
---

# 🛠️ After CoScreen Shut Down, the Original Team Built an Open-Source Petal, This Time No One Can Shut It Down | Open Source Weekly

## Opening

After Datadog shut down CoScreen, the original four-person team rebuilt it as the open-source Petal, which shot to 220 points on Hacker News right out of the gate. In this episode we'll also talk about BetterWispr, a dictation tool that also hit 220 points and 127 comments, plus anatomy, a tool that hit 14k stars in 30 days by having AI draw machines to explain technical concepts. How to use them, coming right up.

## This Week's Open Source Picks

### 1. Petal: The Free Open-Source CoScreen, Turning Screen Sharing into Real Windows on Your Desktop
- **What it is**: After Datadog shut down CoScreen on July 31, 2026, the original four-person team rebuilt it as a free, open-source version (Apache-2.0) to fix the pain point of remote code reviews and pair programming, where "screen sharing turns into a tiled wall and you can't pass your mouse over." The window you share shows up as a genuine native window on the other person's computer, not a tiled frame embedded inside meeting software. That said, the team is upfront that the project is still pre-1.0: the Windows version's own description says "basic sharing works, but still incomplete and buggy," and the Linux desktop app isn't supported yet.
- **This week's buzz**: 220 points on Hacker News (41 comments).
- **Highlights**:
  - The shared window appears as a movable, resizable native window on the other person's desktop, and multiple people can each share their own windows simultaneously
  - Each shared window shows a name-labeled cursor; once you hand over control to a colleague, their mouse clicks and keystrokes get injected directly into that window
  - Named persistent rooms plus `petal://join/<code>` invite links mean you don't have to reopen a scheduling link every time, and you can also log in with a code via meet.petal.live in your browser
- **Quick start**: Download the macOS or Windows desktop app from petal.live and open a room instantly with zero setup using the official hosted service; if you don't want to install anything, just go to meet.petal.live and join with a code in your browser. For full self-hosting, follow docs/SELF_HOSTING.md to run a docker-compose setup, with media routed through a LiveKit SFU so traffic stays on your own network.
- **How it compares**: Compared to Zoom or Google Meet's screen sharing, Petal shares a single window that becomes a native window on your desktop and supports two-way remote control, making it more like the now-defunct CoScreen/ScreenHero. Compared to VS Code Live Share, it isn't tied to any editor, terminal, browser, or Figma, you can share all of them.
- **Who it's for**: Teams doing frequent remote pair programming or cross-timezone code reviews who want a stable tool that no one can shut down again.
- **Link**: [petal.live](https://petal.live/)

### 2. BetterWispr: A Local-Running, Account-Free Dictation Tool for Mac
- **What it is**: Engineers who type dozens of prompts to AI agents every day know how tiring manual typing gets. BetterWispr is a completely free and open-source (Apache-2.0) dictation tool for Mac: hold ⌥ Space, speak, release, and the text gets sent into whatever app you're using. It runs entirely locally, no account, no API key needed, directly addressing the pain point of subscription-based dictation services like Wispr Flow.
- **This week's buzz**: 220 points on Hacker News (127 comments).
- **Highlights**:
  - Built-in local transcription models. The README states plainly, "your voice never leaves your computer unless you add an API connection yourself." You can choose Apple's built-in engine, NVIDIA Parakeet v3/v2, or Whisper large-v3 turbo, and once downloaded, they work offline
  - Automatically strips filler words, repetitions, and self-corrections, with adjustable intensity, and can switch between casual and formal tone depending on which app you're in
  - A meeting-recording mode labels your own voice as "Me" and audio from other apps as "Them," auto-generates a summary when the meeting ends, and includes a vocabulary-learning feature that remembers names and corrections you've made
- **Quick start**: Grab the DMG for your architecture (arm64 or x86_64) from betterwispr.com or GitHub Releases and drag it into Applications, no Homebrew install option. Requires macOS 14 or later, Apple Silicon recommended.
- **How it compares**: Its direct counterpart is subscription dictation services like Wispr Flow. BetterWispr is completely free, requires no registration, and has no cloud fallback. Compared to macOS's built-in dictation, it adds filler-word cleanup, per-app tone switching, dual-channel meeting recording, and the option to swap in Whisper or Parakeet models.
- **Who it's for**: Engineers who spend all day talking to AI agents and would rather not type out every instruction.
- **Link**: [betterwispr.com](https://betterwispr.com/)

### 3. anatomy: Get AI to Invent a Machine to Explain Technical Concepts
- **What it is**: When writing technical docs, making slides, or writing blog posts, explaining an abstract concept (like a rate limiter) often leaves you stuck drawing boxes and arrows. anatomy is an agent skill you install into Claude Code or Codex. Run one command and the AI invents an actual physical machine, using how it operates to turn an abstract concept into an animated, interactive isometric diagram.
- **This week's buzz**: A new project on GitHub within the past 30 days, already at 14.0k stars (13,982 stars), MIT licensed.
- **Highlights**:
  - Instead of drawing abstract boxes, it invents a physical machine to explain the concept, for example, running `/anatomy explain how a token bucket rate limiter works, interactive`
  - Three output tiers: pure SVG (shadows, motion, live readouts), SVG plus WebGL (fire, water flow, caustics, lighting), and a 3D beta (real rotating 3D parts with per-frame relighting), gracefully falling back to SVG if WebGL isn't available
  - Output can be a standalone HTML page, a single SVG file, or a React/Next.js component you drop straight into an existing project. The repo includes eight complete examples, including a percentage gauge, a large arcade machine, and a Raptor 2 engine test stand
- **Quick start**: Run `npx skills add wheresryan22/anatomy -g -a claude-code` (Codex uses `-a codex`; opencode, antigravity, and minimax-code are also supported). After installing, type `/anatomy <你要解釋的東西>` in Claude Code (`$anatomy` for Codex).
- **How it compares**: Compared to diagramming tools like Mermaid, D2, or Excalidraw, anatomy isn't about drawing charts, it generates animated, interactive isometric mechanical illustrations with live readouts. The README itself draws a clear line here too, noting it isn't meant for data visualization and doesn't draw people or maps, and it's intentionally slow because it requires multiple rounds of validation.
- **Who it's for**: Engineers or speakers who frequently need to explain abstract technical concepts to others and want something visually memorable.
- **Link**: [github.com/wheresryan22/anatomy](https://github.com/wheresryan22/anatomy)

## Closing

All three of these are examples of pain points that used to cost money or time, now patched up open-source by a single person or a small team. If I could only install one, I'd go with BetterWispr first, because the moment you install it, you feel the difference. But Petal's story, a tool no one can shut down again, and anatomy turning abstract concepts into moving machines, are both worth keeping in your back pocket too. That's this week's open source roundup. We'll dig up a few more gems same time next week. See you then.

---

## About this article and its author

Originally published on [Mark Ku's Tech Notes](https://blog.markkulab.net/en/open-source-weekly/open-source-weekly-2026-10-17)

License: [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) — when reusing or quoting, credit the author and link back to the original

### About the author

**[Mark Ku](https://blog.markkulab.net/en/author/mark-ku)** — Software engineer

- 10+ years as a software engineer
- Built North-American e-commerce and AI SaaS subscription billing

### Free tools built by the author

All of these are free to use:

- [Free PDF Sign Tool](https://blog.markkulab.net/en/tools/pdf-sign): Online PDF sign tool — draw, type, or upload a signature, then drag, resize, and download. Everything runs in your browser; nothing is uploaded.
- [VS Code Refactory](https://blog.markkulab.net/en/tools/refactory): Refactory is a VS Code refactoring extension: 34 actions plus a 37-rule code-smell inspection layer with a Code Health dashboard, across 18 languages, backed by 534 tests. It learns your repo's conventions: where interfaces live, where DI is registered, whether 'use client' belongs. It ranks files by git churn × complexity so you know what to fix first, and hands any smell to the Claude Code already on your machine. Free to use, and your source never leaves your computer.
- [DB-Kit Database Manager](https://blog.markkulab.net/en/tools/db-kit): DB-Kit is a lightweight, cross-platform database manager built with Tauri + Rust + React. Manage MySQL, MariaDB, PostgreSQL, SQL Server, Oracle, SQLite, MongoDB, Redis, Kafka, Elasticsearch and RabbitMQ from one consistent interface: passwords encrypted in the OS keychain, SSH tunnels, full CRUD, a visual query builder, stacked multi-statement result sets, cross-connection data transfer, schema & data compare with sync SQL and schema snapshots, Excel / CSV import & export, visualized execution plans, ER diagrams, scheduled backups, SQL stress testing with p50–p99 latency percentiles, a 15-rule SQL review engine, Review & Run (AI review plus per-statement backups and an auto-generated rollback script), Kafka message browsing with monitoring & alerts, an SSH terminal with SFTP / FTP, Docker / Kubernetes, remote desktop (RDP / VNC / RustDesk), file / folder compare, stored procedure integration tests, six UI languages, a built-in AI assistant (a local CLI or any Anthropic / OpenAI-compatible API; natural-language SQL, AI review and tuning advice) and the dbk CLI. Free and open source (MIT), with installers for Windows, macOS and Linux.
- [VS Code Super Mermaid](https://blog.markkulab.net/en/tools/super-mermaid): Super Mermaid is a VS Code extension for beautiful Mermaid diagrams out of the box: auto-colored live preview, mouse pan & zoom, high-res PNG / SVG export, 21 templates and multiple themes. Free and open source (MIT).
- [React Super Mermaid](https://blog.markkulab.net/en/tools/react-super-mermaid): react-super-mermaid is an open-source React component library: render beautiful Mermaid diagrams with a single <MermaidViewer>, with built-in colorful / sketch themes, pan & zoom, in-diagram search, and high-res SVG / PNG export. Lightweight, SSR-safe, fully typed. Free and open source (MIT).
- [Jira / Confluence Super Mermaid](https://blog.markkulab.net/en/tools/jira-super-mermaid): An Atlassian Forge app: write Mermaid syntax directly inside a Jira issue or a Confluence page and get flowcharts, sequence diagrams, state machines and Gantt charts. 11 diagram types, SVG / PNG export, light and dark themes, full CJK support. Runs on Atlassian: your diagrams live in your own site and the app calls no third-party service. Free, coming soon to the Atlassian Marketplace.
- [Mermaid Live Preview](https://blog.markkulab.net/en/tools/mermaid-preview): Write Mermaid in your browser, see it render instantly, and share the whole diagram as a single link. No sign-up, nothing uploaded to a server, and mermaid.live share links work as-is.
- [React Intl Phone Number](https://blog.markkulab.net/en/tools/react-intl-phone-number): react-intl-phone-number is an open-source React component: framework-agnostic and antd-free, with E.164 in/out, a searchable flag / country-code dropdown, configurable validation levels (strict / mobile-strict / loose), themeable CSS, and i18n — phone logic powered by google-libphonenumber. Lightweight and fully typed. Free and open source (MIT).
- [Uptime Kuma Cluster](https://blog.markkulab.net/en/tools/uptime-kuma-cluster): Turn single-node Uptime Kuma into a highly available cluster: OpenResty + Lua smart load balancing, shared MariaDB state, health checks and automatic failover, plus cluster-management REST APIs. One Docker Compose command to start. Free and open source (MIT).
- [AI Podcast Cut](https://blog.markkulab.net/en/tools/ai-podcast-cut): Drop in a recording and it removes fillers and stutters, levels loudness segment by segment, and sends a second agent to review every cut. Cut points snap to word boundaries and zero crossings, every splice gets a fade, and sentence-end breaths are preserved. Desktop app for Windows, macOS and Linux. MIT licensed; the Windows installer bundles ffmpeg.
- [AI Video Cut](https://blog.markkulab.net/en/tools/ai-video-cut): Pick something in your video: type it (face, license plate, phone screen, logo), click points or drag a box, or let Claude Code / Codex pick it. AI Video Cut tracks it frame by frame, then mosaics or blurs it, recolors it, pins stickers and text to it, swaps a screen or poster for your own image or video, or removes it using background that other frames actually captured. Plus sequence editing, local captions and an AI assistant. Free, open-source (MIT) Windows desktop app (macOS / Linux experimental) that runs locally, nothing uploaded.
- [open-pos restaurant POS](https://blog.markkulab.net/en/tools/open-pos): One computer and one receipt printer is enough to open the shop. Your data lives on your own disk, no subscription, no lock-in, MIT licensed. Money is integer New Taiwan dollars with tax split by the statutory formula, so sales + tax always equals the total. Printing goes straight over ESC/POS on TCP 9100, with no vendor driver. Tauri + Rust + SQLite desktop app, v1.0 in development.
- [.NET e-commerce API template](https://blog.markkulab.net/en/tools/dotnet-ecommerce-api): An e-commerce backend API template built on .NET 10: Controller → Service → Repository layering, Autofac convention-based registration, SqlSugar for MySQL / MariaDB and SQL Server, Redis cache and message queue, Hangfire jobs, JWT auth, and an extensible payment provider module (ECPay, Newebpay). Apache 2.0.
- [Open Token Monitor team AI usage](https://blog.markkulab.net/en/tools/open-token-monitor): Collect token usage and equivalent cost from every employee's AI coding tools into a hub you host yourself: PostgreSQL, org roster, dashboards compared by company and department, and a reports API. Electron and Rust/Tauri clients upload every 30 minutes. MIT licensed, one Docker command.
- [ai-security-monitor defensive security](https://blog.markkulab.net/en/tools/ai-security-monitor): asa is a single Rust binary for your computers and servers. It finds unusual connections, rates them safe / unknown / suspicious / dangerous against 26 public threat-intel sources, and checks firewalls, open ports, vulnerabilities and 60 hardening rules. Security Hub shows the whole fleet, and Claude Code / Codex explain it in plain words. MIT, free, self-hosted.

### Daily podcasts

- [Mark's Tech Insights — Daily AI News](https://blog.markkulab.net/en/category/tech-news): Daily curated AI and tech trends. Catch the latest developments via audio summaries — covering AI applications, software architecture, DevOps, and engineering practice. — RSS: https://blog.markkulab.net/feed.xml
- [AI股市蝦聊](https://blog.markkulab.net/en/category/ai-stock-chat): Every trading day, an AI-analyzed take on the Taiwan stock market, delivered as a two-host conversation covering the session and the next-day outlook. — RSS: https://blog.markkulab.net/ai-stock-chat/feed.xml
- [開源好物週報](https://blog.markkulab.net/en/category/open-source-weekly): A weekly two-host pick of free open-source tools surfaced from real Hacker News, GitHub, and Reddit buzz — what pain they solve and the fastest way to get started. — RSS: https://blog.markkulab.net/open-source-weekly/feed.xml
- [AI 運動週報](https://blog.markkulab.net/en/category/sports-weekly): Two hosts talk NBA, MLB and world sport three times a week — scores, records and the stories behind them, from a Taiwanese fan perspective. — RSS: https://blog.markkulab.net/sports-weekly/feed.xml
- [AI 國際新聞快報](https://blog.markkulab.net/en/category/world-news): A daily two-host briefing that makes sense of the past 24 hours in world news — geopolitics, the global economy, conflict and security, disasters and climate — from a Taiwanese perspective, neutral and fully sourced. — RSS: https://blog.markkulab.net/world-news/feed.xml
- [地端 AI 實驗室](https://blog.markkulab.net/en/category/local-ai-lab): Twice a week, a two-host look at open-weight models and LoRAs you can actually run on your own machine: what they are for, whether your GPU can handle them, and how they compare — sourced from official model cards. — RSS: https://blog.markkulab.net/local-ai-lab/feed.xml
- [AI 行銷週報](https://blog.markkulab.net/en/category/ai-marketing): Every Tuesday, two hosts break down the week in AI for marketing, advertising, SEO/GEO and content marketing: practical, never sponsored, every story sourced. — RSS: https://blog.markkulab.net/ai-marketing/feed.xml
- [AI 資安週報](https://blog.markkulab.net/en/category/ai-security): Every Thursday, two hosts cover the week where AI meets cybersecurity: LLM and AI agent vulnerabilities, prompt injection, model supply-chain risks and AI-powered attacks, from a defense-first angle with every story sourced. — RSS: https://blog.markkulab.net/ai-security/feed.xml

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