How Do I Know If My SEO Agency Is Quietly Using AI to Write My Content?

What Counts as "AI-Written" Content, Really?

Google does not treat AI authorship as a violation on its own. Its spam policy targets "scaled content abuse" — large volumes of low-value pages made primarily to manipulate rankings, whatever produced them^market. That means the question you should be asking your agency is not "did a model touch this," but "was this written to answer a real question, or to fill a quota."

A single AI-assisted draft that a strategist rewrote, fact-checked, and structured around your customers' actual questions is a different product from a batch of fifty near-identical location pages generated overnight. The second pattern is what search engines penalize. The first is what most competent agencies already do, disclosed or not.

Can AI Content Detectors Actually Catch It?

Not reliably. Independent, non-vendor testing of commercial detectors like GPTZero and Originality.ai finds accuracy in the 62–74% range^market, well short of the 83–99% figures the vendors publish for their own tools. A coin flip with better marketing is still closer to the truth than most agencies want to admit.

Run a detector on three or four articles from your account before you draw conclusions from a single score. One flagged paragraph proves nothing; a pattern across an entire month of deliverables is a different conversation.

Why Do AI Detectors Get It Wrong So Often?

Because the models were trained mostly on native-speaker English, and they penalize anyone who doesn't write like one. Peer-reviewed testing found a 61.3% average false-positive rate on essays by non-native English speakers, against a rate close to zero on native-speaker control text^market. A second, separate study of large-scale writing assessments confirmed the same skew in a different dataset^market.

If your agency employs writers from outside English-speaking countries — common at the price points most SEO shops charge — a "high AI probability" score may be measuring an accent, not a model. Don't fire a writer over a detector score without reading the actual sentences it flagged.

What Are the Telltale Signs an Article Was Written by AI?

Vocabulary is the more reliable tell. Researchers tracking word frequency across millions of documents found a sharp post-ChatGPT spike in words like "delve," "underscore," "intricate," "boast," and "meticulous" — 21 words in total identified as overrepresented in AI-generated text^market. A separate analysis of medical-writing corpora found the same vocabulary shift appearing independently in an unrelated field^market.

Unassisted human reading is not much better than the software, though. Controlled studies put human detection accuracy at roughly 50% against newer models — close to chance — rising to about 70% only for trained evaluators working against older, easier-to-spot text^market. A related linguistic comparison of human- and AI-generated writing reached a similar range^market. Skimming for "AI vibes" is not a method; counting specific words is closer to one.

Does Google Penalize Sites for Publishing AI Content?

It penalizes scale, not authorship. Google's March 2024 enforcement against scaled content abuse deindexed more than 800 sites^market. A follow-up content-composition analysis of the deindexed sites found that 100% contained AI-generated content, and 50% were made up of 90–100% AI-generated pages^market.

That correlation is the actual risk your agency is managing, whether it tells you so or not. A site built to publish hundreds of thin, near-identical AI pages a month sits in the same bucket Google already cleared out once. A site publishing a handful of researched, sourced articles a month does not, regardless of which tool drafted the first version.

How Common Is AI-Written Content at Agencies Today?

Common, but not universal, and the reported share depends heavily on who's answering. A 2026 survey of SEO professionals found 43.2% report using AI tools specifically for writing^market. A separate survey of content marketers more broadly put AI use at 87%^market — a wider question, aimed at a wider group, producing a much higher number.

Neither figure tells you what your specific agency does on your specific account. Ask directly: which stages of the writing process involve a model, and which involve a person checking the model's work.

Should You Ask Your Agency to Disclose AI Use?

Yes, and the market increasingly expects it. 84% of consumers say they want AI-written content labeled as such, against only 20% of organizations that say they always disclose it^market. Undisclosed AI use is also now the single biggest brand turn-off cited by social media users worldwide, named by 28% of respondents^market.

That gap between what buyers want and what agencies do is the actual leverage you have. You don't need to catch your agency lying about AI use — you need to ask them to put their answer in writing before the next contract renewal.

How Do the Four Ways to Check Compare?

None of these four checks is conclusive alone. Together, they triangulate an answer without you needing to buy anything.

Frequently asked questions

Are AI content detectors biased against certain writers?

Yes. Detectors trained mainly on native-speaker English text produce far more false positives on writing by non-native English speakers — a 61.3% average false-positive rate in one peer-reviewed study, against near-zero for native-speaker control text^market. A second, independently conducted study of large-scale writing assessments found the same pattern^market. Treat a "high AI probability" score on a non-native writer's draft with extra skepticism.

What happens if my agency publishes AI content without editing it?

Nothing happens because of the AI itself — Google's spam policy judges scale and value, not the tool used to draft a page^market. The risk is the pattern that unedited AI output tends to produce: thin, repetitive, low-value pages published at volume, the same pattern behind the 800-plus site deindexing event in March 2024^market. Ask to see the editing step, not just the drafting step.

How much of content marketing today is already AI-written?

It depends on who you ask and what they were asked. Among SEO professionals specifically, 43.2% report using AI tools for writing^market. Among content marketers more broadly, a separate survey found 87% report using AI to create or assist with content^market. Neither number tells you what any one agency does on any one account — that requires asking directly.

Can I tell if a blog post was AI-written just by reading it?

Rarely, and not with confidence. Controlled studies find human readers detect AI-generated text at close to chance — around 50% — against newer models, improving to roughly 70% only for trained evaluators working against older, more dated text^market. Watching for a cluster of specific words — "delve," "underscore," "intricate," "boast," "meticulous" — is a more concrete signal than a general impression^market.

What should an AI-disclosure clause in an agency contract cover?

It should state which stages of content production may involve AI tools, require a named person to review and fact-check every draft before publication, and give you the right to ask for a breakdown on any specific piece. It should not ask the agency to promise zero AI use — that promise is unverifiable and, given how common AI-assisted writing already is across the industry, unlikely to be true anyway.