Understand what
changed in a PR —
before you review it.

A GitHub Action that reads your PR diff and posts a structured analysis: what changed, why it matters, what risks exist, and where to focus.

Add to GitHub Upgrade to Pro — $5/mo View source
.github/workflows/explainer.yml
# That's it. Zero config beyond this. name: PR Explainer on: pull_request: types: [opened, synchronize, reopened] jobs: explain: runs-on: ubuntu-latest steps: - uses: dwylq/pr-explainer-action@v0.2.0 with: anthropic-api-key: ${{ secrets.ANTHROPIC_API_KEY }}
The problem

AI writes code fast. Reviewing it still takes forever.

Cursor, Claude Code, Copilot — they make writing code fast. But reviewers still face PRs with 50+ changed files and no signal of what actually matters.

50+
files changed in a typical AI-generated PR. Most reviewers skim the first few and miss the rest.
$0.01
cost per PR analysis. Cheaper than one minute of a senior engineer's time reading a diff.
What you get

Not a summary. A briefing.

Every PR gets a structured analysis comment — specific to the actual files, functions, and patterns that changed.

comment on PR #142

## What Changed

Added OAuth token refresh in src/auth/oauth.ts — the new refreshAccessToken() function exchanges an expired access token for a new one. The user model in src/models/user.ts gained a refresh_token TEXT column with NOT NULL — breaking migration.

## Why It Matters

This introduces persistent session storage. Users will need to re-authenticate on first deployment after this ships.

## Risks

Medium Refresh tokens stored as plain text in users table

High No rate limiting on /auth/refresh endpoint

Medium Migration adds NOT NULL to table with 10K+ existing rows

## Focus Review On

Token storage approach — plain text refresh tokens in the database is a security concern. Verify migration handles existing rows.

How it works

Five steps. Zero config.

01

Trigger

Fires automatically on PR open, sync, or reopen. No manual triggers needed.

02

Fetch

Gets the complete PR diff via the GitHub API. No checkout step required.

03

Analyze

Sends diff to Claude with an expert reviewer system prompt. File-level, specific analysis.

04

Comment

Posts a structured analysis comment directly on the PR. Visible to all reviewers.

Philosophy

Explainer, not reviewer.

Reviewers judge — they tell you what's wrong with your PR.
Explainers help — they help you understand what changed so you can review faster.

The goal isn't to replace human review. It's to make human review faster and more focused. Every comment includes a risk badge so you can scan PR health at a glance.

Get started

Install in under a minute.

One workflow file. One secret. That's all it takes.

Create a workflow file

Add .github/workflows/explainer.yml to your repo.

Set your API key

Add ANTHROPIC_API_KEY to your GitHub repo secrets. Free tier gives ~$5 credit.

Open a PR

Every new PR gets an analysis comment. Review with context, not confusion.

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