Whiteboard

Whiteboard is an open-source canvas for thoughtful software development, provided by /dev/fast under an MIT license. It runs on macOS, Windows, and Linux, and can be downloaded or viewed through its source repository. The tool centers on visualizing code changes and agent interactions from a single interface.

When you open a project in Whiteboard, you can load a diff and see a semantic representation of the changes. The underlying diff engine is written in Rust, so the text is parsed into an abstract syntax tree before rendering. In the sidebar you can slide over individual lines and hover to reveal examples of the AST element, or to open a call‐tree view that shows function signatures and call relationships. The viewer can also collapse code to show a pseudocode summary, while preserving the original source so you can navigate to any line. When you select a fragment of the diff, a copy command places the exact snippet on the clipboard, ready for pasting into an LLM chat for clarification or code review.

Whiteboard is designed for teams that want to audit agent behaviour or review architecture‐level changes. It exposes a Diff Search API that accepts normalised hit objects or JSON produced by a caller‑run command. The API offers three steps: `parseHits`, which normalises file:line:text records; `hydrate`, which validates hits against the Git repository and returns full file comparisons; and `postprocess`, which runs any installed plugins over the selected comparisons. Plugins are fully extensible and can modify visibility, highlight evidence, or rename symbols. The interface lets you drag selections onto a diagram pane to generate sequence diagrams, database diagrams, or call trees, and you can expand pseudocode back into the original source.

Key features

• Semantic diffs powered by an AST library written in Rust
• View long algorithms as pseudocode with signature visibility
• Hover over rows to see corresponding AST examples on the right pane
• Fully extensible with a plugin architecture for custom post‑processing
• Diff Search API that parses, hydrates, and postprocesses hits from a Git repo
• Copy and paste snippets directly into an agent for conversational review