AI Grammar Fixer

Their is possessive — their coats. There is a place, or the dummy subject in there is a problem. They're is the contraction of they are, and the apostrophe stands in for the missing a. The test is expansion: read the sentence with they are in place of the word, and if it still makes sense, they're is right. If not, ask whether something belongs to them, which gives their. Anything left over is there. The same expansion sorts your and you're, and its and it's — the form carrying the apostrophe is always the contraction, never the possessive.

A comma splice is two complete sentences joined by nothing but a comma: the report is late, I will send it tomorrow. Both halves could stand alone, and a comma is not strong enough to hold them. Four fixes exist. A full stop separates them cleanly. A semicolon keeps them linked when the second thought completes the first. A comma plus and, but or so makes the relationship explicit, which is usually the best of the four. A colon works when the second half explains the first. A run-on sentence is the same fault with no comma at all.

It is optional in British usage and standard in most American style guides, so the practical rule is to pick one and hold it across the whole document. The argument for it is ambiguity: without it, the last two items can read as a pair — I thanked my parents, Ann and Bob suggests that Ann and Bob are the parents. The argument against is clutter in short, plain lists. Where a list contains appositives or an internal and, put it in. Otherwise the choice is house style rather than grammar, and it is the inconsistency a reader notices.

Choose by audience rather than preference. A British employer, university or client expects colour, organise and licence as a noun; an American reader expects color, organize and license. Mixing the two inside one document is what reads as careless, and it usually happens by accident — text pasted together from different sources, or typed on a machine set to the other locale. Set your editor's language before you start rather than repairing it afterwards. The differences run past spelling: date order, collective nouns taking a plural verb in British English, and got rather than gotten as a past participle.

No, and the advice to delete every instance is overapplied. The passive puts the action first and the actor late or nowhere: the file was deleted. That is exactly right when the actor is unknown, irrelevant or obvious, and it is the normal register in scientific and legal writing. It becomes a problem when it hides responsibility — mistakes were made — or when it stacks up until a paragraph loses its energy. The useful test is whether you can name the actor and whether naming them helps the reader. If both, rewrite. A checker that flags every passive construction is counting, not reading.

Put time between writing and checking — a night if you have one, twenty minutes if you do not — because you cannot proofread what you still have memorised. Then change how the text looks: a different font, a narrower column, paper instead of a screen. Reading aloud catches missing words and sentences that run out of breath, because your mouth stumbles where your eye skates. For typos, read the last sentence first and work backwards, which breaks the meaning and forces you to see the words. Check names, numbers and dates in a separate pass; that is where the expensive errors live.

It depends on the tool. Some checkers run a dictionary inside the page and never make a request. This one cannot: there is no spell checker in the browser here, so your passage is placed in a JSON request, posted to this site's own /api/ai route, and forwarded from the server to Anthropic — the whole thing, including every part that was already correct. The route itself writes nothing to a database, and the page keeps no history, so a reload or a second run clears what was there. Treat it as you would any text handed to someone else's service, and keep other people's personal details and anything under an NDA out of it.

Rules differ, and the line most institutions draw is between correcting and composing. Fixing spelling, punctuation and agreement in work you wrote is generally treated like a proofreader or a writing centre; having a model produce the argument, the structure or the sentences is not. The grey area is a proofreader that quietly rewrites, which is the reason to compare the returned text against your own — if whole sentences have changed shape, that is past the line for most coursework. Check the policy that applies to you. Detection tools judge only the text in front of them and are unreliable in both directions.