What this actually does
This runs your text through a set of rule-based passes entirely in your browser: swapping common "AI-sounding" filler phrases for plainer equivalents, swapping a couple thousand formal or clichéd words for more conversational alternatives, turning some "do not" / "cannot" style phrasing into contractions, occasionally merging short choppy sentences or splitting overly long ones, and occasionally opening a sentence with a casual lead-in or a hedge ("I think", "arguably"). Nothing is sent to a server - the whole pipeline runs as JavaScript on this page.
Why the same text always gives the same result
The amount of change is controlled by your Mode and Intensity choice, but within a single run the randomness is seeded from the text itself, so re-running the exact same input on the exact same settings reproduces the exact same output - it does not reroll every time you click, which makes it easier to compare settings or reproduce a result later.
Why it won't reliably beat an AI detector
This will not reliably defeat an AI-detection tool. Detectors look at statistical patterns across a whole passage - token-probability distributions, not just the presence of a handful of telltale phrases - so swapping words and reshuffling some sentences changes the surface wording without necessarily changing the deeper pattern a detector is measuring. Treat this as a writing-polish tool, not a way to disguise AI-written work in a context (like a school assignment) where that would be dishonest.
What the before/after grade level shows
The grade-level numbers use the same Flesch-Kincaid formula as this site's Readability Checker tool, based on average sentence length and average syllables per word. A lower number after running the tool usually means shorter sentences and simpler words came out of the swap and restructuring passes - it is a side effect of the rewriting, not a target the tool is specifically optimizing for.
What this can't do
It doesn't understand meaning, so it can't add the specific, concrete detail that makes writing feel genuinely distinct, and it won't fix generic structure or a repetitive argument. The sentence restructuring is pattern-based (looking for short neighboring sentences to merge, or long sentences to split at a comma), not a grammar parser, so occasionally a merge or split will read a little awkwardly - always read the result before using it.
Choosing a mode and intensity
Formal keeps changes light and skips casual contractions and lead-ins, for text that needs to stay professional. Casual leans into contractions and conversational openers. Aggressive and Creative push every pass harder for text that needs to change the most. Intensity scales how often each pass fires, independent of which mode you pick.