What AI detector do colleges and teachers actually use, if any?

The platform does not detect, the add-on does

Canvas, made by Instructure, has no built-in AI writing detector. Instructure's own blog on academic integrity in Canvas describes AI writing and similarity reports as arriving through the Turnitin integration, which instructors can set per assignment: full checks on major essays, lighter checks on drafts, none on reflective work. On the Instructure Community forum, requests for a native detector were redirected to feature ideas, and a Canvas administrator argued that detection should stay with external partners. So if a Canvas course flags AI, a third-party tool was licensed and enabled by the institution.

Google Classroom is the same. Google's help page on how an originality report is created says the report uses Google Search to compare a student's file against webpages and books, plus prior submissions from the school if an administrator turns that on. It flags uncited passages that match a source. Nothing on the page describes detecting AI-generated text, and a purely AI-written essay with no copied passages returns no flags.

Where Turnitin fits

Turnitin's AI writing FAQ confirms the indicator is available through Moodle, Blackboard, Canvas and other LMSs, but only inside the Similarity Report and only for institutions that license Turnitin Originality and have an administrator enable it. Turnitin does not process submissions for AI writing where the feature is off. The short version: instructors see a percentage and highlights; students see nothing unless the instructor shares a PDF.

Where GPTZero and the free tools fit

GPTZero, ZeroGPT, QuillBot, Copyleaks and Grammarly sell or give away web checkers that any teacher can use by pasting text. Copyleaks advertises LMS plug-ins for Canvas, D2L, Moodle, Blackboard, Schoology, Edsby and Sakai, and Originality.ai lists a Moodle plugin. Installed in an LMS these are institutional purchases; used from the free page they are a teacher's personal habit, which bypasses whatever policy and privacy review the institution did.

The institutions that turned it off

Vanderbilt University's Brightspace team published a statement in August 2023 explaining that it had disabled Turnitin's AI detector "for the foreseeable future". Its reasoning: at Turnitin's stated 1% false positive rate, the 75,000 papers Vanderbilt submitted in 2022 would imply around 750 wrongly flagged; the tool arrived with less than 24 hours' notice and no way to disable it; Turnitin had not explained how it worked; and detectors had been shown to flag non-native English writers. Vanderbilt concluded it did not believe AI detection software was an effective tool that should be used, and pointed instructors towards clear course policies, comparison with a student's earlier work, and redesigned assignments.

Which platforms detect AI writing

Platform	Has AI detection?	Source
Turnitin	Yes, when the institution licenses Turnitin Originality and enables it; instructor-only, inside the Similarity Report	Turnitin AI writing FAQ
Canvas (Instructure)	No native detector; AI checks come via integrations such as Turnitin	Instructure blog on Canvas and Turnitin
Google Classroom	No; originality reports match text against web pages, books and school submissions	Google Classroom help
GPTZero and other free checkers	Yes, as standalone tools or LMS plug-ins the institution chooses to add; accuracy is contested (accuracy thread)	GPTZero technology page
Vanderbilt University (example institution)	Turnitin AI detection disabled since August 2023	Vanderbilt statement

What that means in practice

• Find out what your institution licensed. The syllabus or academic integrity office will say whether Turnitin Originality is on; a Canvas or Classroom submission box by itself proves nothing.
• A flag from a free tool is a teacher's personal check. It carries whatever weight the institution's policy gives it, which may be none, and the student thread covers how to respond.
• Policies are diverging. Some universities lean on Turnitin, some have switched it off, and the same tool can be evidence in one department and inadmissible in the next.