Previously, MCP agents had to read/write local files to update designs. Now, the agent connects directly to the running editor via SSE.
You type a prompt, and the UI nodes update on the canvas in real-time. Zero file I/O latency.
We also shipped strict security hardening for local agent execution (write allowlists, path traversal guards, env sandboxing).
Actually, there have been commits to the repo every day. The duplicate submissions today were a genuine accident on my part—I got a bit confused by the submission system as a first-timer and accidentally posted it again. My apologies for that.
I completely respect HN's guidelines on self-promotion. Going forward, I will only post updates here when there is a major version release or a significant architectural change. Thanks for understanding!
Hey! I'm the creator of OpenPencil, and I'm super excited to share it with you today.
We are entering the era of AI Agents, but our design tools are still stuck in the GUI era. We are constantly downloading "final_v9.fig" and manually clicking to tweak UI elements. I wanted to change that.
OpenPencil isn't just another design tool with a magic AI button. It is structurally built for AI.
Here is why it's different:
Agentic Design (MCP Server): You can connect Claude, Cursor, or any MCP-compatible agent directly to your design. Tell your AI IDE to "update the login screen to match the new dark mode theme," and it modifies the design file without you ever touching a mouse.
Design-as-Code: The .op format is pure JSON. Finally, you can Git commit, diff, and PR your design files just like your codebase.
100% Open Source (MIT): No subscriptions, no vendor lock-in. Build on top of it, fork it, make it yours.
I built this because I believe the future of design is Human creativity + Agent execution.
I'd love your feedback! Drop your questions below, and let me know what features you want to see next!
OpenPencil is an MIT-licensed, AI-native vector design tool. It features a built-in MCP server, allowing AI Agents (like Claude Code or Cursor) to directly edit designs without a GUI. Thanks to its Design-as-Code architecture, all files are structured JSON, enabling version control and Git diffs for design.
