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AI detector, humanisers and plagiarism checkers

By Alberto Gulotta · Updated · 7 min read

This is the entrance to the detection tower. An ai detector, a humaniser, a plagiarism checker, a grammar tool — four kinds of software that all claim to tell you something true about a piece of writing.

It is the most contested tower on this island, because a claim about a piece of writing can be acted on: a percentage can become an accusation, and somebody can be asked to prove they wrote their own sentences. An industry has grown on both sides of that argument at once, which is why every claim on these floors is traced to whoever made it.

So the tower begins where the honest reading begins. Detection is probabilistic. A score is an estimate expressed as a number, and a number looks a great deal more settled than the estimate underneath it. Every floor in the first wing says what its tool states it is measuring, and what a result can and cannot support.

Which is also why the humaniser wing exists and is not hidden. Tools that rewrite text to defeat detectors are searched for in numbers we have measured, and leaving them out would make this tower less useful without making it more honest. Those floors explain what the tools do, and where using them stops being a style choice and becomes something else.

The plagiarism and grammar wings are calmer. Those tools are older and better understood, and the questions there are narrower: which one, at what price, and what happens to your text after you paste it in — which each floor answers from the service’s own terms.

Three levels, and you are on the first. This atrium lists the floors; a floor covers one subject completely and holds the shorter guides underneath. Nothing here is more than three clicks from the front door.

One more thing belongs at the door, because it is the sentence most readers of this tower actually need. If you have been accused of using AI to write something you wrote yourself, the accusation rests on a probability presented as a fact, and it is contestable. Detectors do not treat all writing the same — plain sentences, careful structure, and text written by people composing in a second language. That is a documented pattern rather than a grievance, the floor about it sets out what evidence helps, and the evidence that helps most is the one nobody keeps: the draft history. If you are reading this before anything has gone wrong, that is the single most useful habit in this building.

Where to start

Seven ways in.

“I have been accused of using AI and I did not.”
Start at ai detectors
“I need to check a student’s work.”
Read the limits floors in ai detectors
“How accurate are these things really?”
That is the central floor of ai detectors
“What is a humaniser and does it work?”
Go to humanisers
“I need to check for plagiarism before submitting.”
That is plagiarism
“I want my writing checked for mistakes.”
The grammar floors are in writing tools
“Does the tool keep what I paste into it?”
Every wing answers that — writing tools

AI detectors

One floor per detector, each answering the same questions: what it claims, what independent testing has found, what it does with the text you submit, and what a given score can honestly support.

How accurate they areA university turned a percentage into people, published the arithmetic, and switched the tool off.Open this guide → What a score meansHow these tools reach a percentage, and why the number is more confident than the method.Open this guide → False accusationsWho is flagged most often, why, and what to do when it happens to you.Open this guide → GPTZeroWhat the company publishes about its method and its accuracy, with the date.Open this guide → Turnitin’s AI detectionThe one most students meet, and what institutions are told about its limits.Open this guide → Originality AIThe detector aimed at publishers and agencies rather than at students, read on its own pages.Open this guide → CopyleaksThe other commercial detector in the same market, and who it is sold to.Open this guide → If you are accusedThe evidence that actually helps, the research on who gets flagged, and how to assemble it before replying.Open this guide →

Humanisers

The other half of the argument. These floors describe what the tools do and are explicit about where the line sits, rather than pretending the category does not exist.

Where the line isWhat a university and a major publisher actually wrote down, and where each of them draws the line.Open this guide → Paraphrasing toolsThe older and more legitimate cousin of the humaniser, and what it is for.Open this guide →

Plagiarism

Older technology, better understood, and largely doing what it says. The questions here are about coverage, price, and what happens to your document afterwards.

How checkers workWhat they compare against, and the large parts of the internet they cannot see.Open this guide → TurnitinThe one used by institutions, and how to read a similarity report properly.Open this guide → Self-plagiarism and citationReusing your own work, and the rules that differ by institution.Open this guide →

Writing tools

Grammar, style and word count. It is the least contested wing in the tower, the one where the free options come closest to the paid ones, and the one where the honest advice is often to stop paying.

Grammar checkersWhat each one catches, and the point at which suggestions start flattening your voice.Open this guide → Is Grammarly Premium worth itThe six things the paid tier adds, quoted from the current pricing page, and the plan name that changed.Open this guide → Word and character countersSimple tools, and the one thing worth checking before pasting a whole document into one of them.Open this guide → Is Grammarly safeWhat the current policy says it does with your text, and the company name that changed underneath it.Open this guide →

Not covered here. It will not tell you a detector is reliable enough to accuse somebody. No floor in this tower supports that, and where a company implies it, the floor quotes the company and then quotes the independent testing next to it.

It will not help anybody cheat. The humaniser floors explain what the tools do because people search for them in enormous numbers and deserve an accurate answer rather than a sermon, and each of those floors is equally explicit about where the line is.

It will not rank the detectors yet. That needs paid accounts, a controlled set of texts we wrote ourselves, and published results — which is the only kind of test worth anything in this category, and it takes weeks.

And it will not carry affiliate links, which in this tower means turning down some of the highest commissions on the entire island. What holds instead is simple: no detector on these floors is presented as proof of anything, and no floor here carries an affiliate link of any kind.

Written by Alberto Gulotta

Founder and editor of AI Tools Primer, writing from Palermo, Italy. Thirty-five years of taking computers apart, starting with a Commodore 64 — the long version is on the about page.

Something wrong on this page? Write to aitoolsprimer@gmail.com and it gets fixed.

Written on 20 August 2026 · last checked 2 September 2026.

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