Whiteboard (YC W26) - a design session with your coding agent, on a canvas

Coding agents now write more code than a small team can read, and the risk is merging changes nobody understands. Whiteboard plugs into Claude Code or Codex and has the agent draw its work: sequence and entity diagrams you click through to the code behind them.

- A semantic diff viewer written in Rust shows only the changes that matter: big new functions as pseudocode, tests and docs collapsed
- A decision log shows which choices the agent made on its own and how they shaped the change
- Free and open source (MIT), runs on local checkouts; macOS only for now, Windows is on the roadmap

330+ points on Show HN this week. Worth a look for any founder who reviews agent PRs and wants to still understand the system six months from now.

https://github.com/devdotfast/whiteboard

📎 Read also:
→ Harden - a guard for what your coding agent is about to run
→ KanBots - parallel coding agents with a hard cost cap
→ Kanwas - a canvas where humans and agents share context