The tool
What the Claude assignment checker does
Paste your draft and press Analyze. The checker reads the text you gave it and writes back what it notices: the patterns in the sentences, where the writing goes vague, what reads as filler. It is a second pair of eyes on a draft before you hand it in.
The analysis runs on our server, so the text you paste is sent to us. You get 5 free runs every rolling 24 hours, no account, and an input of between 1 and 12,000 characters. There is an optional instruction box of up to 300 characters if you want to point the analysis at something specific, like the introduction or the argument in the third section.
The difference
Why this assignment checker gives no percentage
Almost every page competing for this term hands back a number. Grammarly returns a percentage of the work that "appears to be written with AI". QuillBot returns 0 to 100% with sentence-level highlights. Detector-checker.ai returns a 0 to 100 score in three bands: likely human-written, uncertain, likely AI-written.
This one returns none of that, and not by omission. The analysis is written as findings you can act on, in sentences, because a number tells you nothing you can edit. QuillBot puts the problem in its own guidance better than we could: "Scores are signals, not verdicts. Never make an academic or employment decision on a detector score alone." We agree, so we do not produce the signal that gets mistaken for a verdict.
How it works
How to check an assignment in three steps
One pass of this takes about a minute and is worth doing before the final read-through, not instead of it.
- Step 1
- Paste the draft, or the section you are least sure about. There is no minimum length here, so a single paragraph is a valid input.
- Step 2
- Add an instruction if you have one, up to 300 characters. Naming the thing you are worried about gets you a more useful answer than a general request.
- Step 3
- Read the findings against your own draft and edit what you agree with. The output is an opinion about your writing, not a mark and not a pass or fail.
The blind spots
What an assignment checker cannot see
It sees the text you paste and nothing else. It does not have your assignment brief, so it cannot tell you whether you answered the question. It does not have the marking rubric, so it cannot predict a grade. It has no plagiarism database and no reference index, so it cannot verify that a citation exists or that a quotation is accurate.
That matters because those are the things assignments are actually marked on. Treat this as a check on how the writing reads, then check the brief, the sources and the word count yourself. No tool competing for this term will do those three for you either.
Why good writing gets flagged
Academic writing trips AI detectors
This is the part students find unfair, and the detectors admit it. QuillBot names its own worst case: "heavily paraphrased writing and highly formulaic content, such as legal jargon or academic writing, is more likely to present a false positive." That is a description of a literature review.
Detector-checker.ai makes the same point from the other direction. It declines to list Claude-specific tells because "polished answers, cautious tone, consistent sentence structure" show up in careful human writing too. If you have been taught to write in a measured, hedged, structurally consistent way, you have been taught to write in the way a detector scores as machine-like.
The blunt question
Can any checker prove who wrote an assignment?
No, and the more careful detectors say so on their own pages. Detector-checker.ai states that "the tool does not identify the source model", that it cannot confirm Claude produced a passage, and that it cannot tell Claude Sonnet, Opus and Haiku apart. Grammarly writes that "currently there is no AI detector that can conclusively or definitively determine whether AI was used", on the same page as a 99% accuracy claim.
This checker never makes an authorship claim at all. It describes what is observable in the text in front of it and says what it cannot tell. If you need to know whether AI was used in a piece of work, the answer comes from talking to the person who wrote it, not from a tool.
If you have been flagged
What to do when an assignment gets flagged
Do not start editing to move a number. Both Grammarly and QuillBot advise the opposite of that, and QuillBot puts it plainly: "If you used AI in your work, disclose it rather than revising to change a score." Rewriting to beat a detector produces worse writing and leaves you with nothing to say if you are asked about it.
What helps is evidence of process: drafts, notes, version history, the sources you actually read. What also helps is your institution's own policy, which Grammarly correctly points out is the thing that governs, not any tool's output. Use a checker to improve a draft, not to build a defence.
Limits, stated
What this Claude assignment checker will not do
No score, no bands, no sentence highlighting, no grade. No file upload: Grammarly takes a file and detector-checker.ai takes a 5 MB document, while this takes pasted text into a box capped at 12,000 characters. No plagiarism check, no citation lookup, no batch mode, no API and no account.
It also will not tell you what Turnitin, GPTZero or Originality.ai are going to say about your work. We have no relationship with any of them and no way to predict their output, and the detectors themselves concede that editing moves their results in either direction.