PR Lens: Interactive Architecture Walkthroughs for Pull Requests

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Ohans Emmanuel has presented Coldtea AI's open-source tool PR Lens, which visualises pull requests as animated architecture and data-flow walkthroughs inside GitHub comments.

Key points

  1. PR Lens generates animated data-flow and architecture diagrams directly within pull request comments.
  2. A colour-coded blast radius highlights new (green), modified (amber), and removed (red) components and interactions.
  3. An interactive walkthrough steps through changes one at a time, dimming irrelevant cards and supporting pan and zoom on a full canvas.
  4. It can be deployed as a GitHub App, GitHub Action, CLI, or as a coding agent skill via `npx skills add coldteadotai/pr-lens`.
  5. Emmanuel states the primary design goal is reducing cognitive load during reviews, with native GitLab integration currently in progress.

Why it matters

As coding agents produce increasingly large pull requests, reviewing raw code diffs becomes mentally exhausting. Providing animated, structured visual context before reading individual lines helps reviewers grasp data flows and architectural impact much faster.

Analysis

Prompted by discussions on reviewing AI-authored code, PR Lens moves beyond static diagrams like Mermaid by providing interactive, stepped explanations. The core design prioritises architecture and flow tracing. While Emmanuel notes this model assumes architecture and data flow are paramount, it addresses a major pain point in modern code reviews.

Original post

Ohans Emmanuel

@OhansEmmanuel · 7 September 2026

Mermaid diagrams are the floor. Every PR at @ColdteaAI ships with an interactive walkthrough Open source: t.co/y9KsaeosGs t.co/2kAWOq9zwW t.co/fs0b6IbSg3

1.2k likes41 replies2.5k bookmarks175.1k views

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More posts in the thread (10)
  1. Try the walkthrough in the video here: t.co/DXuVOop71R
  2. @AkrShakil @ColdteaAI Can’t wait to hear feedback :)
  3. @hirletz @ColdteaAI Technically you can make it work yourself via your coding agent (local mode) We’re still working on a native Gitlab integration
  4. @oguzcanhuner @ColdteaAI It assumes architecture and data flow are what matters most But this may not be true for a small subset of apps But I think most apps can have whatever’s really important expressed this way: security, accessibility etc The other downside (or more of a todo later) is it
  5. @marvinaziz @ColdteaAI You and me :)
  6. @m31uk3 @ColdteaAI It’s a good tool. But you’re right, I don’t believe it’s optimised for agent diffs / reducing cognitive overload
  7. @yesadok @ColdteaAI Haha, that’s the design. To reduce the cognitive load first and foremost
  8. @TheCodingSloth1 @ColdteaAI Give it a try! Let’s do a YT? :)
  9. @transitive_bs @ColdteaAI You're about to have an amazing dev flow :)
  10. @allstonbuilds @ColdteaAI Let me know if you v any feedback when you do
Selected replies (5)
  • @m31uk3 @OhansEmmanuel @ColdteaAI I love the idea of mermaid. I struggle to get value from 90% of the mermaid diagrams I read. There’s some function of attention to detail and density that mermaid rendering still lacks. I’m still an advocate, but I wouldn’t choose mermaid for PRs.
  • @yesadok @OhansEmmanuel @ColdteaAI interactive walkthroughs actually make me want to review the code
  • @ross_axilio @OhansEmmanuel @ColdteaAI Super useful! Love a good mermaid diagram
  • @UditKhandelwal8 @OhansEmmanuel @ColdteaAI Absolutely! That's a no brainer..Made open source MCP Server with GitHub action for PR walkthroughs from the coding session itself t.co/E224xMr5Jj
  • @dev_aqueiroz @OhansEmmanuel @ColdteaAI @OhansEmmanuel thanks for sharing. I have used it. It is a good start, but got hard to use on our code. There were many lines coming out of a box and there was no way to highlight a single one to see where it went. Maybe our arch is not good, but it is what it is 🤷

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Summary generated by AI (Gemini 3.8 Flash, 27 September 2026). It may contain errors – the original source is authoritative.

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