PR Lens

PR Lens is an open-source tool by Coldtea AI that reduces the cognitive load of reviewing AI-generated pull requests by converting diffs into animated SVG architecture and data-flow diagrams posted directly inside the PR as a bot comment. It is MIT-licensed, available on GitHub, and currently at version v0.1.3.

What It Is

PR Lens sits between a code diff and a human reviewer. Instead of reading hundreds of changed lines across many files, a reviewer sees a single animated diagram showing what the change touches, how data flows through the new path, and which nodes are new, changed, or removed — all rendered in color-coded, animated SVG that survives GitHub's image proxy. Two diagram "lenses" ship: an architecture lens (blast radius against the existing system) and a data-flow lens (ordered pipeline, animated with moving pulses).

Five Ways to Use It

PR Lens offers multiple deployment modes, all producing the same diagrams from the same underlying document format:

• GitHub App — Install the hosted app on a repository; every PR automatically gets a sticky bot comment that updates on each push. View-option checkboxes are live in this mode, re-rendering from the stored graph in seconds with no model key required from the user.
• Coding agent skill — Run npx skills add coldteadotai/pr-lens to teach a coding agent (Cursor, Claude Code, etc.) to write the graph document itself and attach it to the PR, reusing the agent's existing model rather than incurring a separate API bill.
• GitHub Action — Add a workflow file using coldteadotai/pr-lens/packages/action@v0 with a GEMINI_API_KEY (or OpenAI-compatible) secret; the Action analyzes the diff and posts a static comment from your own CI.
• CLI — Run npx @coldtea/pr-lens-cli step by step: analyze, render, comment, validate, and export commands give full control on any machine.
• Local terminal — Render diagrams before a PR even exists, useful for reviewing an agent's work alongside the diff.

Architecture and Renderer

The renderer is a bespoke SVG engine — not Mermaid — designed specifically for easy comprehension of code changes. It uses a consistent visual grammar: lanes, node cards, delta colors (green = new, amber = changed, red = removed), and routed edges that stay traceable even in dense graphs. The renderer scales from a single-card minimal diagram (1 lane, 1 node, 0 edges) up to monorepo-scale graphs (6 lanes, 37 nodes, 49 edges). Animated pulses in data-flow diagrams move along arrows in the order steps execute, with activation bars for waited-on calls and open arrowheads for fire-and-forget messages. Every diagram on the project page is regenerated deterministically from checked-in fixtures.

Package Structure

The repository is a TypeScript monorepo (Node 20.11+, pnpm 10) with five packages:

• @coldtea/pr-lens-schema — the contract every component speaks
• @coldtea/pr-lens-renderer — deterministic JSON graph → animated, theme-paired SVGs
• @coldtea/pr-lens-cli — analyze, render, compose, validate, export
• packages/action — the GitHub Action
• @coldtea/pr-lens-agent-skill — teaches a coding agent to draw the change it just made

Update: v0.1.3

The latest release is v0.1.3, published on 2026-08-26. The repository was created in August 2026 and has seen active development, with the last push on 2026-08-26. The GitHub App runs on Gemini by default with no user model key required; the CLI and Action also support OpenAI and any OpenAI-compatible endpoint (OpenRouter, DeepSeek, Ollama, self-hosted servers).