Most SEO tools are built on best guesses dressed up as best practices.
Someone with a popular blog writes a thread. It gets shared. An agency turns it into a checklist. A tool turns the checklist into a score. And before long, thousands of business owners are optimising their content based on a chain of opinions — with no direct line back to how Google actually works.
I built SEO ContentSpy differently.
Every signal it checks is traceable to a publicly available source — a Google patent, an official Google documentation page, or a published AI retrieval research paper. No opinions. No guesswork. Just the signals Google itself has told us it uses.
Here’s what that means in practice.
Yoast gives you a green light when your keyword appears enough times in your content. Surfer SEO gives you a content score based on what the top-ranking pages have in common.
Both approaches are directionally useful. But neither one is sourced.
When Yoast tells you your keyword density is too low, it doesn’t cite a Google patent. When Surfer tells you to add more words, it doesn’t reference a Google documentation page. They’re reverse-engineering signals from observed outcomes — which works until Google changes something, and suddenly your green dot means nothing.
SEO ContentSpy skips the reverse engineering. It goes directly to the source.
Every page that goes through SEO ContentSpy is analysed across three proprietary signal sets: Authority Signals, Rankability Signals, and Citability Signals.
Each one is built on documented evidence — not observation.
Authority is about trust. Google doesn’t rank content equally — it ranks content from sources it has reason to trust. The Authority signal set checks your content against Google’s E-E-A-T framework: Experience, Expertise, Authoritativeness, and Trustworthiness.
This isn’t a framework I invented. It comes directly from Google’s Search Quality Rater Guidelines — the document Google uses to train the human evaluators who assess page quality. It’s publicly available. Anyone can read it.
The sources:
This is where it gets interesting.
Rankability answers one question: has this page been built in a way that Google can understand, process, and reward?
The signal set checks 8 factors — three of which are sourced directly from Google patents. Public record. Patent numbers and everything.
| Signal | Source |
|---|---|
| Entity Analysis | US10235423B2 — Scoring Entity Mentions |
| User Engagement | US10229166B1 — Modifying Search Result Ranking Based on Implicit User Feedback |
| Heading Structure | US11409748B1 — Passage-Based Ranking |
| Content Quality & Depth | Google’s Helpful Content guidance |
| Title & Meta | Google Search Central documentation |
| Salient Terms | Google’s Natural Language API documentation |
| Schema & Structured Data | Google’s Structured Data guidelines — schema.org |
| Freshness | Google’s QDF (Query Deserves Freshness) algorithm |
Every one of these is a signal Google has publicly documented. You can look up the patents. You can read the documentation. The signal exists. It’s in writing. We’re just checking whether your content accounts for it.
Search is no longer just Google.
ChatGPT, Perplexity, and Google’s own AI Overviews are now pulling content and citing sources directly inside their answers. The businesses and writers who get cited in those answers get traffic and visibility without a single person clicking a traditional search result.
Citability checks whether your content is structured in a way that AI retrieval systems can find, understand, and reference.
The sources:
Most tools stop at the diagnosis. They hand you a score or a list of issues and leave you to figure out what to do next.
SEO ContentSpy diagnoses and fixes. It tells you what’s wrong — and then it writes the fix. Weaker sections rewritten. Keyword gaps filled. Headings restructured. You review it, approve it, and publish it.
One thing it doesn’t do: analyse backlinks. This tool is about the quality of what’s on your page — not who’s linking to it. Backlinks matter for rankings, but they’re a separate problem. SEO ContentSpy focuses on making your content worth linking to in the first place.
When your SEO tool is built on Google’s own documentation, two things happen.
First, you stop chasing signals that don’t matter. A lot of SEO advice is cargo cult optimisation — doing things because others do them, not because there’s documented evidence they work. Cutting that out saves time and money.
Second, you stop being surprised by algorithm updates. When Google updates its systems, tools built on reverse-engineered signals often break. Tools built on Google’s documented principles are far more stable — because the foundations don’t change as often as the outcomes.
SEO ContentSpy is free. It runs as a Custom GPT inside ChatGPT. No login. No credit card. You paste a URL and get a full audit in under a minute.
Solo dev. Revenue-focused SEO consultant. Creator of SEO ContentSpy. Good governance advocate. Outside of work he loves freediving and goofing around with his wife and 2 kids.
