Automated PR Code Reviews with GitHub, GPT-4, and Google Sheets Best Practices

Description

AI-Agent Code Review for GitHub Pull Requests

Description:

This n8n workflow automates the process of reviewing code changes in GitHub pull requests using an OpenAI-powered agent.

It connects your GitHub repo, extracts modified files, analyzes diffs, and uses an AI agent to generate a code review based on your internal code best practices (fed from a Google Sheet).

It ends by posting the review as a comment on the PR and tagging it with a visual label like ✅ Reviewed by AI.

🔧 What It Does
Triggered on PR creation

Extracts code diffs from the PR

Formats and feeds them into an OpenAI prompt

Enriches the prompt using a Google Sheet of Swift best practices

Posts an AI-generated review as a comment on the PR

Applies a PR label to visually mark reviewed PRs

✅ Prerequisites
Before deploying this workflow, ensure you have the following:

n8n Instance (Self-hosted or Cloud)
GitHub Repository with PR activity
OpenAI API Key** for GPT-4o, GPT-4-turbo, or GPT-3.5
GitHub OAuth App** (or PAT) connected to n8n to post comments and access PR diffs
(Optional) Google Sheets API credentials if using the code best practices lookup node.
⚙️ Setup Instructions

1. Import the Workflow in n8n, click on Workflows → Import from file or JSON
Paste or upload the JSON code of this template

2. Configure Triggers and Connections

🔁 GitHub Trigger

Node**: PR Trigger
Repository**: Select the GitHub repo(s) to monitor
Events**: Set to pull_request
Auth**: Use GitHub OAuth2 credentials

📥 HTTP Request

Node: Get file's Diffs from PR

No authentication needed; it uses dynamic path from trigger

🧠 OpenAI Model
Node**: OpenAI Chat Model

Model**: Select gpt-4o, gpt-4-turbo, or gpt-3.5-turbo

Credential**: Provide your OpenAI API Key

🧑‍💻 Code Review Agent
Node : Code Review Agent
Connected to OpenAI and optionally to tools like Google Sheets

💬 GitHub Comment Poster

Uses GitHub API to post review comments back on PR
Node: GitHub Robot
Credential: Use the agent Github account (OAuth or PAT)
Repo : Pick your owen Github Repository

🏷️ PR Labeler (optional)
Adds label ReviewedByAI after successful comment

Node: Add Label to PR
Label : you ca customize the label text of your owen tag.

📊 Google Sheet Best Practices config (optional)
Connects to a Google Sheet for coding guideline lookups, we can replace Google sheet by another tool or data base

First prepare your best practices list with the clear description and the code bad/good examples
Add al the best practices in your Google Sheet
Configure* the Code *Best Practices node** in the template :
Credential : Use your Google Sheet account by OAuth2
URL : Add your Google Sheet document URL
Sheet : Add the name of the best practices sheet