LintGuardian: Automated PR Linting with n8n & AI

What It Does

LintGuardian is an n8n workflow template that automates code quality enforcement for GitHub repositories. When a pull request is created, the workflow automatically analyzes the changed files, identifies linting issues, fixes them, and submits a new PR with corrections. This eliminates manual code style reviews, reduces back-and-forth comments, and lets your team focus on functionality rather than formatting.

How It Works

The workflow is triggered by a GitHub webhook when a PR is created. It fetches all changed files from the PR using the GitHub API, processes them through an AI-powered linting service (Google Gemini), and automatically generates fixes. The AI agent then creates a new branch with the corrected files and submits a "linting fixes" PR against the original branch. Developers can review and merge these fixes with a single click, keeping code consistently formatted with minimal effort.

Prerequisites

To use this template, you'll need:

1. n8n instance : Either self-hosted or using n8n.cloud
2. GitHub repository : Where you want to enforce linting standards
3. GitHub Personal Access Token : With permissions for repo access (repo, workflow, admin:repo_hook)
4. Google AI API Key : For the Gemini language model that powers the linting analysis
5. GitHub webhook : Configured to send PR creation events to your n8n instance

Setup Instructions

1. Import the template into your n8n instance

2. Configure credentials :

   • Add your GitHub Personal Access Token under Credentials → GitHub API
   • Add your Google AI API key under Credentials → Google Gemini API

3. Update repository information :

   • Locate the "Set Common Fields" code node at the beginning of the workflow

   • Change the gitHubRepoName and gitHubOrgName values to match your repository

     const commonFields = { 'gitHubRepoName': 'your-repo-name', 'gitHubOrgName': 'your-org-name' }

4. Configure the webhook :
   Create a file named .github/workflows/lint-guardian.yml in your repository replacing the Trigger n8n Workflow step with your webhook:

   name: Lint Guardian

on:

  pull_request:
    types: [opened, synchronize]

jobs:
  trigger-linting:
    runs-on: ubuntu-latest
    steps:
      - name: Trigger n8n Workflow
        uses: fjogeleit/http-request-action@v1
        with:
          url: 'https://your-n8n-instance.com/webhook/1da5a6e1-9453-4a65-bbac-a1fed633f6ad'
          method: 'POST'
          contentType: 'application/json'
          data: |
            {
              "pull_request_number": ${{ github.event.pull_request.number }},
              "repository": "${{ github.repository }}",
              "branch": "${{ github.event.pull_request.head.ref }}",
              "base_branch": "${{ github.event.pull_request.base.ref }}"
            }
          preventFailureOnNoResponse: true

5. Customize linting rules (optional): * Modify the AI Agent's system message to specify your team's linting preferences * Adjust file handling if you have specific file types to focus on or ignore

Security Considerations

When creating your GitHub Personal Access Token, remember to:

• Choose the minimal permissions needed (repo, workflow, admin:repo_hook)
• Set an appropriate expiration date
• Treat your token like a password and store it securely
• Consider using GitHub's fine-grained personal access tokens for more limited scope

As GitHub documentation notes: "Personal access tokens are like passwords, and they share the same inherent security risks."

Extending the Template

You can enhance this workflow by:

• Adding Slack notifications when linting fixes are submitted
• Creating custom linting rules specific to your team's needs
• Expanding it to handle different types of code quality checks
• Adding approval steps for more controlled environments

This template provides an excellent starting point that you can customize to fit your team's exact workflow and code style requirements.