Whiteboard - Open-source IDE for thoughtful software design
Show HN: Whiteboard (YC W26) – An open-source IDE for thoughtful software design
Whiteboard is an open-source desktop app where humans and AI agents architect software together on a shared canvas. It plugs into Claude Code, Codex, and other coding agents, giving them an SDK to draw diagrams, sequence flows, and decision logs right next to the code. A semantic, AST-aware diff viewer cuts through noisy changes, while clickable visualizations jump straight to the underlying source. MIT-licensed and running on your local checkouts, Whiteboard turns opaque agent output into reviewable, understandable design decisions.
Diagrams that lead to code: when you click on visualizations like a sequence diagram or an entity relationship diagram, you can jump to the underlying code directly.
- bbor
Oh WOW, cool to see a technique that'll be everywhere in 12 months (the fake pen drawing animations + streaming diagrams as they're produced) first be announced. Do we still do "First!" comments, y'all?
~~[EDIT: you need to put "only for macOS" in way more prominent places, all over -- that offends my soul greatly and may Linus frown upon you all]~~ [EDIT2: I was mistaken!]
This all looks really solid. That said, two remarks:
1. The integration with OS LSPs is quite fun and commendable. Is it possible that the diagrams might get their own LSP, someday? Or is better just staying as direct TS callsites?
2. The choice of the word "IDE" seems like it might get you in trouble, given the small "cannot edit files" detail. Any comments on the decision there, as opposed to, say... "brainstorming tool"? Or hell, "[architectonic] harness"?
3. The psuedocode "semantic diff" thing is an incredible idea, wow. Props there.
4. This language kinda concerns me: "how the requirements that you set were implemented". In my highly-arbitrary development flow, it ideally goes `idea -> spec/reqs -> plan -> test -> impl -> eval -> land -> review`, and this kind of tool seems explicitly targeted towards just the second and third with some partial coverage of their neighbors on either side. More concretely: by adding implementation, don't you lose a powerful specificity selling point and now have to compete with all full harnesses?
5. Suggesting "GPT-6 Luna and Claude Opus 5.5" is presumably a typo? Cau […]
- icar
You cannot currently edit files in Whiteboard. If this is something that you find yourself wanting to do, please file an issue!
Do you still consider this an IDE? Curious
- DylanMerigaud
Semantic diffs in Rust enhance code understanding significantly.
- nickosh
Thanks! The project looks great and I am definitely interested in this approach. I hope it will help me with my usual issue - I review a lot of code these days and it's really hard to understand what changes about and why they even needed usually, without deep analysis and AI sessions. It's always good to have such a visual method to check briefly what's there on architecture and design level - these mistakes are hardest to find in other people's code, as it is for me.
I especially like your way to connect agents - I'm basically using what I wish to use, without limitations or pay walls. At my work, all AI tools should be reviewed and approved before usage but here I just use my coding agent and this is "plugin" for visualisation, so I guess it will be approved in no time. Thanks to not keeping a forced data collection, it will really help to promote your tool in corporate environments.
No reasons to not try it for me! I am looking closely at what will come next and will try to share my feedback, if there will be some.
For now, I just feel that it will be good to have a way to trigger review creation from the app itself, not to create a new agent session for this. Kinda a bit counterintuitive but I understand why it works this way and it's not a real issue.
- vladzoff
I can see the value of having the agent and the human looking at the same design. The thing I'd worry about is the diagram becoming another thing that slowly diverges from the code. Would be interesting to see how you handle that once the implementation starts moving.
- bad_haircut72
I use https://whiteboard-mcp.com in a similar way to this - it gives me a drawing canvas claude can access and read
- heltale
This is a good development in terms of processing information for people.
Visual memory comes the easiest to people and it’s the quickest way to understand and convey information to most people.
Other forms of memory that I expect to see having better tools to address them are auditory and kinesthetic.
- 2001zhaozhao
This is definitely getting at least some things right about how we work with agents today, specifically that we often work at the architecture level, and we need a better alternative to the current Plan Mode offered by coding agents to efficiently architect software at a high level, which is more visual and offers better back-and-forth incrementation with the agent than simply "reject final plan with X message".
From the website demos i definitely think this is a clean interface, although I don't know how much better this is compared to some simple custom Mermaid format, which the agent can write as artifact files and present to users. Zooming out, this app seems like 1 feature (a MCP with a GUI attached to it) rather than an entire product.
Also, I don't know if asking the agent to write specific code changes into the plan is a good idea. I think maybe that a "plan -> approve -> write code" would let the agent write higher quality code than "plan which contains code -> approve". But maybe you can make it work when combined with some specific prompting marking the code as clearly work-in-progress and subject to change, and that the agent should surface any parts implemented differently relative to the plan to the user, etc.