Forty changed files—and one dangerous question
Your AI agent just changed 40 files. You're about to approve the pull request, but can you actually explain what it did? This is the central paradox of agentic development: an AI can generate dozens of modifications in seconds, but a human developer still owns the decision to merge.
Fast code generation shifts the bottleneck from typing to understanding. Suddenly, reviewing involves dissecting intent, tracing dependencies, and predicting potential regressions across a sprawling codebase. This is where tools like Whiteboard, an open-source app by devdotfast from Y Combinator's Winter 2026 batch, come into play.
Whiteboard aims to make these large, agent-generated changes legible. It doesn't just create impressive-looking diagrams; it provides a map of what your agent did. The real test for Whiteboard isn't aesthetic, but whether its interactive sequence diagrams and AST-aware diffs genuinely help a human reviewer explain and verify the proposed changes.
Can Whiteboard simplify the complex task of reviewing an AI agent's work? I’m looking for clarity on the logic that actually changed, not just a pretty picture. The goal is to ensure you understand what you are about to merge before it ships.
A map that leads straight to the code
Whiteboard tackles this paradox by making your agent draw a map of its changes, instead of just dumping a paragraph of text. It generates interactive request-flow and sequence diagrams. These diagrams show how changed components connect, providing a high-level overview of the agent’s work.
Crucially, these aren't static images or basic Mermaid blocks. Each step in a Whiteboard diagram links directly to the corresponding function in your code. This lets you move seamlessly from a high-level flow to the precise implementation without hunting through dozens of files.
This direct linkage is Whiteboard’s killer feature. Unlike a chat summary or a static diagram, Whiteboard’s map is anchored to the actual code you need to inspect. You can follow the explanation and verify it against the implementation, ensuring you understand exactly what you’re about to merge. This makes the review process far more efficient and less prone to "AI slop."
Whiteboard, an open-source tool from devdotfast and a Y Combinator Winter 2026 batch company, runs entirely on your machine. It uses your own agent and posts nothing to GitHub, maintaining your privacy and control. It’s licensed under MIT, emphasizing its commitment to open source and developer autonomy.
The diff cuts noise—not the need to think
Whiteboard's review view aims to cut through the noise. It lets you fold away boilerplate like tests and documentation, and summarizes large functions as pseudocode. What remains is the core logic that actually changed, making it easier to spot meaningful modifications.
This selective presentation isn't just a clever trick; it’s powered by a custom AST-aware diff engine written in Rust. This engine understands code structure, not just text, which is key to intelligent summarization. Extensible WASM plugins further enhance its flexibility.
Instead of just presenting a wall of text, the tool helps you quickly scan what matters. But don't mistake visual structure for certainty. You still need to inspect relevant code, validate behavior, and assess tests.
Whiteboard offers a guide, not a substitute for your judgment. You’re still responsible for confirming what the agent did. For more technical details, including its MIT license and YC Winter 2026 batch origins, check out devdotfast/whiteboard: Open-source Canvas for Thoughtful Software Design. It’s about making your review faster, not making your brain redundant.
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Local-first, but does it earn another canvas?
Whiteboard’s MIT license and local-first design address the practical concerns around AI-generated code review. It runs entirely on your machine, using your existing agent and keys, and avoids posting review content into GitHub, which keeps your team’s internal discussions private.
This isn't a replacement for your IDE, coding agent, or cloud PR-review bot. Instead, Whiteboard acts as a dedicated companion review surface, built on CodeOSS. It specifically supports CLI agents like Claude Code and OpenAI Codex, providing a visual explanation for their changes.
The real test, as always, comes down to adoption. Does the time Whiteboard saves and the confidence it provides outweigh the friction of integrating another tool into your workflow? For complex, multi-file changes from an AI agent, a visual map of the request flow could be the key to catching subtle misunderstandings before they hit your main branch.
Frequently Asked Questions
What is Whiteboard?
Whiteboard is an open-source tool that visualizes code changes from AI agents as interactive diagrams linked to the relevant source code.
How does Whiteboard help review AI-written code?
It maps request flows, links diagram steps to functions, and presents a focused diff that can de-emphasize tests, documentation, and unchanged boilerplate.
Does Whiteboard post comments to GitHub?
The tool is designed to run locally and keep its review experience off GitHub, rather than publishing automated PR comments.
Is Whiteboard open source?
Yes. Whiteboard is released under the MIT License.