Tutorial: Auto-update documentation when code is merged

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What you will build

• Code repository: Where you store application code. You’ll set up the GitHub webhook on this repository. Examples include a backend API, frontend app, SDK, or CLI tool.
• Documentation repository: Where you store your documentation and connect to your Mintlify project. The agent creates pull requests with documentation updates in this repository.

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Workflow overview

1. Someone merges a pull request in the code repository.
2. n8n receives the webhook from GitHub.
3. n8n sends the pull request context to the agent API.
4. The agent creates a pull request in the documentation repository.

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Prerequisites

• n8n workspace
• Mintlify admin API key
• Mintlify Pro or Custom plan
• Admin access to the GitHub repositories for your code and documentation
• GitHub personal access token

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Get your admin API key

1. Navigate to the API keys page in your dashboard.
2. Select Create Admin API Key.
3. Copy the key and save it securely.

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Get your GitHub personal access token

1. In GitHub, navigate to Settings.
2. Click Developer settings.
3. Click Personal access tokens.
4. Click Tokens (classic).
5. Click Generate new token (classic).
6. Select these scopes:
   • repo (full control of private repositories)
   • admin:repo_hook (if you want n8n to create webhooks)
7. Generate and save the token securely.

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Build the workflow

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Create the webhook trigger

1. In n8n, create a new workflow.
2. Add a webhook node.
3. Configure the webhook:
   • HTTP Method: POST
   • Path: auto-update-documentation (or any unique path)
   • Authentication: None
   • Respond: Immediately
4. Save the workflow.
5. Copy the production webhook URL. It looks like: https://your-n8n-instance.app.n8n.cloud/webhook/auto-update-documentation

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Set up the GitHub webhook

1. Navigate to your code repository on GitHub.
2. Click Settings.
3. Click Webhooks.
4. Click Add webhook.
5. Configure the webhook:
   • Payload URL: Paste your n8n webhook URL
   • Content type: application/json
   • Which events would you like to trigger this webhook?
     • Select Let me select individual events.
     • Select only Pull requests.
   • Select Active
6. Click Add webhook.

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Filter for merged pull requests

1. Add a code node.
2. Name it “Filter merged PRs.”
3. Set mode to Run Once for All Items.
4. Add this JavaScript:

const webhookData = $input.first().json.body;

// Only continue if this is a closed AND merged PR
if (webhookData.action !== "closed" || webhookData.pull_request?.merged !== true) {
  return [];
}

// Extract information
const pullRequest = webhookData.pull_request;
const repository = webhookData.repository;
const sender = webhookData.sender;

// Build message for agent
const agentMessage = `Update documentation for changes in ${repository.name} **PR #${pullRequest.number}: ${pullRequest.title}** Always edit files and create a pull request.`;

return {
  json: {
    prTitle: pullRequest.title,
    prBody: pullRequest.body || "No description provided",
    prNumber: pullRequest.number,
    prUrl: pullRequest.html_url,
    prAuthor: sender.login,
    codeRepoName: repository.full_name,
    codeRepoShortName: repository.name,
    branchName: pullRequest.head.ref,
    filesChanged: pullRequest.changed_files,
    agentMessage: agentMessage
  }
};

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Call the agent API

1. Add an HTTP request node.
2. Name it “Create agent job.”
3. Configure the request:
   • Method: POST
   • URL: https://api.mintlify.com/v1/agent/YOUR_PROJECT_ID/job (replace YOUR_PROJECT_ID with your project ID from the API keys page of your dashboard)
   • Authentication: Generic Credential Type → Header Auth
     • Create a new credential:
       • Name: Authorization
       • Value: Bearer mint_YOUR_API_KEY (replace with your API key)
   • Send Body: On
   • Body Content Type: JSON
   • Specify Body: Using JSON
   • Add this JSON:
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   {
   "branch": "docs-update-from-{{ $json.codeRepoShortName }}-pr-{{ $json.prNumber }}",
   "messages": [
       {
       "role": "system",
       "content": "{{ $json.agentMessage }}"
       }
   ]
   }
   

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Activate the workflow

1. Save your workflow.
2. Set it to active.

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Test the automation

1. Create a test branch in your code repository:
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   git checkout -b test-docs-automation
   

2. Make a small change and commit it:
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   git add .
   git commit -m "Test: trigger docs automation"
   git push origin test-docs-automation
   

3. Open a pull request on GitHub.
4. Merge the pull request.

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Verify the automation

• n8n executions: You should see a new execution with all nodes completed successfully.
• Documentation repository: After a minute or two, check for a new branch and pull request with documentation updates.

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Troubleshooting

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Webhook not triggering

• Verify the workflow is active in n8n.
• Check GitHub repository Settings → Webhooks → Recent Deliveries for the response code.
• Confirm the webhook URL matches your n8n webhook URL exactly.

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401 error from agent API

• Verify your API key starts with mint_.
• Check the Authorization header is formatted as Bearer mint_yourkey.
• Confirm the API key is for the correct Mintlify organization.

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401 error from GitHub

• Verify your token has the repo scope.
• Check that the token hasn’t expired.
• Confirm you included the User-Agent header in the GitHub request.