Seven signs text was written by AI

These are countable. You can run them past a tool and get a number rather than an impression, which is what makes them more useful than vibes-based detection.

1. Em dashes at a steady rate. Chat models produce the em dash (—) far more consistently than people do, because typing one requires a keyboard shortcut most writers never learned. One or two in a long document is normal. Roughly one per paragraph, evenly spread, is not. The em dash guide covers why the habit is so entrenched.

2. Curly smart quotes and typographic punctuation. AI output tends to arrive with directional quotation marks (" "), curly apostrophes ('), and a real ellipsis character (…) rather than three full stops. Word processors also produce these automatically, so they are only meaningful in contexts where autocorrect was never involved — a plain-text field, a code comment, a CSV file.

3. Invisible Unicode characters. Zero-width spaces, non-breaking spaces, and narrow no-break spaces frequently survive a copy-paste out of a chat window. They are undetectable by eye and are the single strongest mechanical marker, because almost nothing a human types by hand introduces them.

4. Emoji-headed bullet lists. Structured answers with a decorative emoji at the start of each bullet, section headers built from bold text rather than real headings, and lists nested three levels deep are a house style that chat interfaces encourage and most human writers do not use.

Style-level patterns are much easier to get wrong, because plenty of careful human writing shares them. Treat these as prompts to look closer, never as findings.

5. Hedged, evenly balanced framing. Sentences that present every question as having two reasonable sides, paragraphs that open by restating the question, and closing lines that summarise without adding anything. This comes from training that rewards being helpful and non-committal at once.

6. The "not just X, but Y" construction. Along with "it's worth noting that", "delve into", "navigate the complexities of", and "in today's fast-paced world". These phrases are not banned words — they are ordinary English. What stands out is how often they cluster together in a single short piece.

7. Unusually uniform structure. Paragraphs of near-identical length, sections with a suspiciously equal number of bullets, and a conclusion that mirrors the introduction. Human drafts are lumpier; a paragraph runs long because the writer had more to say about that particular thing.

The vocabulary signals in particular decay quickly. Every list of "AI words" that circulates gets absorbed into how people write and into how the next generation of models is tuned. Mechanical signs are more durable because they are byproducts of encoding, not of style.

A practical order of operations, cheapest check first:

1. Scan for invisible characters. This is the highest-signal, lowest-effort check. Paste the text into the Invisible Character Scanner — it lists every zero-width space, soft hyphen, byte-order mark, and direction mark it finds, with counts.
2. Count the mechanical artefacts together. The AI Text Cleaner reports em dashes, smart quotes, invisible characters, and emoji in a single pass, so you can see whether several signals co-occur rather than chasing one at a time.
3. Read for the stylistic patterns. Only after you have the counts. Numbers first stops you from talking yourself into a conclusion.
4. Weigh the context. Text pasted from Word will carry smart quotes regardless of who wrote it. Text typed into a plain textarea will not.

Co-occurrence is what matters. A single em dash means nothing. Em dashes and smart quotes and two zero-width spaces and emoji bullets, in a document that was typed directly into a plain-text form, is a genuinely unusual combination.

Every sign above has an innocent explanation.

Word and Google Docs convert double hyphens into em dashes and straight quotes into curly ones automatically. Copying from any modern website can carry invisible characters. Professional editors write in exactly the balanced, hedged register that reads as machine-generated. Non-native English speakers often write in a more formal, structurally regular style, which is precisely why commercial AI detectors flag their work at markedly higher rates.

There is also the obvious circularity: a person can paste AI output into a text editor, run a cleanup pass, and remove every mechanical sign in about ten seconds. The signals that are easiest to measure are also the easiest to erase.

So the honest position is this. Formatting analysis tells you what characters are in a document. It cannot tell you who put them there. Our tools deliberately report counts and never render a verdict, because a verdict would be a guess wearing a number as a disguise. If you need to know whether a person wrote something, the answer comes from talking to them about it — draft history, sources, and the ability to explain their own argument — not from counting dashes.