Automate AI Summaries for WordPress with n8n, OpenAI & Slack

1. Opening Problem Statement

Meet Maria, a content manager for a growing blog about electric vehicles. Every week, Maria spends countless hours manually reading newly published WordPress posts and crafting concise summaries to include at the top of each article. These summaries help readers quickly grasp the key points and improve SEO, but the process is time-consuming and repetitive. On top of that, Maria sometimes misses adding summaries for new posts due to oversight, leading to inconsistency and lost reader engagement.

This manual task not only wastes roughly 3-4 hours weekly but also opens the door for errors such as duplicate summaries or forgotten updates. Maria wishes there were a way to automatically generate intelligent, well-formatted summaries for each new post and keep track of which posts have been processed without installing bulky WordPress plugins that might slow down her site.

2. What This Automation Does

This unique n8n workflow is designed specifically for Maria’s problem. When activated, it automatically:

• ✅ Detects new or updated WordPress posts, either on a scheduled basis or via a secure webhook trigger.
• ✅ Retrieves the post content directly from WordPress and converts its HTML into Markdown for better AI understanding.
• ✅ Uses OpenAI’s GPT-4o-mini model with a custom system prompt to generate a clean, bullet-point HTML summary optimized for WordPress embedding.
• ✅ Updates the original WordPress post by adding the AI-generated summary block at the top, while preserving the original excerpt for SEO quality.
• ✅ Logs the processed posts into a Google Sheets document to prevent duplicate processing and maintain an accessible summary archive.
• ✅ Sends a notification message to a dedicated Slack channel, informing the team about the new AI summary post-update.

By automating these steps, Maria saves at least 4 hours every week, eliminates manual errors, and ensures every post is uniformly summarized, enhancing reader engagement and site SEO.

3. Prerequisites ⚙️

• n8n automation platform account (Cloud or Self-hosted) 🔌
• WordPress website with API access and credentials 🔐
• OpenAI API key for GPT-4o-mini model access 🔑
• Google Sheets account with a sheet for logging AI summaries 📊
• Slack workspace integration with a channel for notifications 💬

If you prefer to self-host your automation for full control and privacy, consider hosting options like Hostinger’s n8n hosting.

4. Step-by-Step Guide

Step 1: Choose Your Trigger Method

Navigate to the Trigger node options.

• Manual Trigger: For testing, select “Manual Trigger” to start your workflow on demand.
• Schedule Trigger: Enable “Schedule Trigger” to run the workflow every fixed interval (e.g., every 5 minutes). Configure the interval under rule settings.
• Webhook Trigger: Enable the Webhook node, set the webhook path and authentication header to secure the trigger. Use your WordPress site or a plugin to call this webhook when a post is published.

You should see the trigger node active when ready, and test the trigger by posting manually or waiting for schedule execution.

Common mistake: Forgetting to enable the trigger node or incorrect webhook authentication leading to no execution.

Step 2: Retrieve WordPress Posts

Use the “WordPress – Get All Posts” node to fetch posts during testing or “WordPress – Get Last Posts” with a filter based on the last execution timestamp when running on schedule.

Configure API credentials with your WordPress API token. For production, disable fetching all posts to avoid hitting API limits.

Upon execution, expect a list of posts with their IDs, content, and metadata.

Common mistake: Not using the correct “context=edit” option to get raw post content needed for updating later.

Step 3: Loop Over Each Post

Add the “Loop Over Items” node to sequentially process each post, which optimizes resource use and ensures each post is handled individually.

Connect it after the posts fetching node to feed all items one by one downstream.

Common mistake: Removing this node when multiple posts are retrieved causing bulk processing overloads.

Step 4: Check Google Sheets for Existing Summaries

Configure the “Google Sheets – Get rows” node to look up the current post ID in your tracking sheet to see if it’s already summarized.

Use the post ID as the lookup value and map it to the column that contains post IDs in your sheet.

If Node: Add an IF node immediately after the Google Sheets lookup to decide whether to continue processing the post. The condition checks if the post_id exists in the sheet.

Posts already present skip AI processing to avoid duplication.

Common mistake: Mismatching column names between n8n and Google Sheets causing false negatives.

Step 5: Retrieve Full Post Content and Convert HTML to Markdown

For posts marked as needing summaries, use “WordPress – Get Post2” to fetch the full post data with raw HTML.

Then pass this content to the “HTML to Markdown” node to convert it to Markdown format, which helps OpenAI models better understand formatting.

Common mistake: Forgetting to specify the correct field containing HTML content for conversion.

Step 6: Classify Post Content with Text Classifier Node

Send the Markdown content to the “Text Classifier” node that uses an LLM classifier to detect if the content already contains an AI summary or not.

The node outputs “summarized” or “not_summarized” in JSON format, which determines downstream branching.

Common mistake: Not following the strict JSON response format expected by the classifier node, causing processing errors.

Step 7: Generate the AI Summary with OpenAI

Configure the “OpenAI” node with the GPT-4o-mini model and the detailed system prompt that instructs the model to create a bullet-point summary in HTML format styled for WordPress.

Send the Markdown content as input data. You can customize the system prompt to fit your blog’s theme.

Example system prompt excerpt:

You are an expert in content summarization and web-optimized writing...
Generate only an HTML block containing a concise summary in bullet point format...

Common mistake: Using an outdated or generic prompt, leading to suboptimal or unusable summaries.

Step 8: Update WordPress Post with AI Summary

Use the “Wordpress – Update Post” HTTP Request node to POST the updated content to WordPress. Combine the generated AI summary with the original post content. Also, update the excerpt field carefully to preserve manual excerpts.

Configure API credentials and test with a sample post ID.

Common mistake: Overwriting the excerpt unintentionally or incorrect API endpoint causing update failures.

Step 9: Log Summary Data into Google Sheets

Configure the “Google Sheets – Add Row” node to append a row with the post ID, summary, summary date, and relevant links for tracking and auditing.

Ensure column names match exactly with your Google Sheet schema for auto-mapping.

Common mistake: Changing sheet structure after setup without updating node causes logging failures.

Step 10: Notify Slack Channel

Use the “Slack – Notify Channel” node to send a formatted message with the post title, links to the post and edit page, and the post ID, so your team stays informed about updates.

Configure OAuth2 credentials with appropriate Slack workspace permissions.

Common mistake: Using an incorrect channel ID or insufficient Slack app permissions blocking notifications.

Step 11: Set Fields for Google Sheets and Slack

Before logging and notifications, use the “Set fields – Prepare data for Gsheets & Slack” node to assemble and format all necessary data fields, such as post_id, title, summary, post_link, edit_link, and summary_date.

Modify this node to include extra metadata if needed, such as categories or authors.

5. Customizations ✏️

• Personalize AI prompt: Modify the OpenAI system prompt in the “OpenAI” node to reflect your blog’s niche beyond electric mobility, improving summary relevance.
• Change summary styling: Adjust the HTML block’s CSS properties in the prompt response template to match your WordPress theme’s colors and fonts.
• Add extra fields to logs: In the “Set fields – Prepare data for Gsheets & Slack” node, add fields like post author or categories for richer tracking in Google Sheets and Slack notifications.
• Switch trigger mode: Prefer event-driven updates? Enable and configure the Webhook node for instantaneous AI summaries upon post publication.
• Batch size adjust: In the “Loop Over Items” node, change batch size if you handle large post volumes to balance performance and API rate limits.

6. Troubleshooting 🔧

• Problem: “Trigger node does not activate”
  Cause: The trigger node (Schedule or Webhook) is disabled.
  Solution: Ensure your preferred trigger node is enabled in n8n and test connectivity or auth tokens.
• Problem: “WordPress API returns 403 or 401 errors”
  Cause: Incorrect or expired WordPress authentication credentials.
  Solution: Double-check API tokens, update OAuth or JWT credentials, and verify user permissions.
• Problem: “Google Sheets lookup fails to find rows”
  Cause: Mismatched column names or improper sheet sharing permissions.
  Solution: Confirm column headers exactly match field names defined in n8n and ensure your service account has access rights.
• Problem: “OpenAI node returns errors or empty responses”
  Cause: API key issues, rate limits, or malformed prompts.
  Solution: Verify your OpenAI API key, monitor usage, and use the exact system prompt format recommended.
• Problem: “Slack notifications do not appear”
  Cause: Wrong channel ID or insufficient OAuth scopes.
  Solution: Check the configured Slack channel ID and OAuth permissions, reauthorize if needed.
• Problem: “Post summary updates overwrite the excerpt incorrectly”
  Cause: Wrong field mapping or payload in the update post node.
  Solution: Ensure the excerpt field only updates when necessary and test with a sample post.

7. Pre-Production Checklist ✅

• Verify trigger node (Schedule or Webhook) is enabled and functional by performing a test run.
• Confirm WordPress API credentials with appropriate permissions to read and update posts.
• Test Google Sheets access with a sample lookup and insert operation; verify column mappings.
• Validate OpenAI API connectivity and correct system prompt setup.
• Check Slack notification delivery on a test message.
• Ensure no duplicate summaries exist by clearing or reconciling existing Google Sheets data.
• Run multiple tests on a small batch of posts before scaling to all posts.

8. Deployment Guide

Activate your chosen trigger node (Schedule Trigger for automated intervals or Webhook Trigger for real-time execution). Ensure all credentials are saved and tested in n8n’s settings.

Monitor executions via n8n’s execution logs to catch any failures early. Adjust batch size or schedule frequency as needed to fit your publishing cadence and API limits.

Slack and Google Sheets integrations provide real-time monitoring and easy audit trails.

For long-term maintenance, periodically review prompt efficacy and update the system prompt to match evolving content themes.

9. FAQs

• Q: Can I use other AI models besides GPT-4o-mini?
  A: Yes, you can switch to other OpenAI models available in your API key, but consider cost and response quality differences.
• Q: Does this workflow incur high API costs?
  A: Costs scale with the number of posts processed and summary length. Using the text classifier helps avoid redundant API calls, optimizing usage.
• Q: Is my WordPress data safe?
  A: Yes, all API connections are secured with authentication. Running on self-hosted n8n further enhances control and security.
• Q: Can this handle large blogs with hundreds of posts?
  A: Yes, but adjust batch sizes and schedule intervals to maintain performance without hitting API rate limits.

10. Conclusion

By implementing this comprehensive n8n workflow, you have automated the tedious and error-prone task of generating AI-powered summaries for your WordPress posts. Maria can now spend her valuable time focusing on content creation instead of manual editing. The process guarantees consistent, clear summaries enhancing both user experience and SEO performance.

This solution saves you at least 4 hours per week, reduces human error, and keeps your content team notified via Slack—bringing modern AI and cloud tools together seamlessly.

Next steps could include automating social media sharing of new posts, integrating content translation APIs, or setting up deeper analytics by connecting your summaries to business intelligence tools.

Ready to automate your blogging workflow? Let’s set it up and watch your productivity soar!