What's rising, what's fading
Direction reflects the newest available data. Several tells are now falling at the source while still rising in human speech and the published record.
Most "AI-isms" are shared across every model. But each one has habits distinct enough that a classifier can name the author. Confidence labels: measured = quantitative study · documented = widely reported, official acknowledgment, or dedicated tracking · anecdotal = community consensus without hard counts.
ChatGPT (OpenAI)
- "It's not just X, it's Y." Negative parallelism, in ~6% of sampled real messages. measured
- Em dashes as a brand. Highest measured rate of the big models; Altman announced a fix in Nov 2025 that made custom instructions work, but defaults barely moved until GPT-5.4. measured
- The "delve" era vocabulary. Delve, tapestry, underscore, showcase: the 2023–24 tells, now fading from new output while still spreading through human speech. Watch instead for "core" and "modern". measured
- Markdown maximalism. Heaviest user of bold text, headers, and "Bold term: explanation" bullets. measured
- Sycophancy spike. The April 2025 GPT-4o update was rolled back within a week for being "overly flattering"; GPT-5 then overcorrected cold and was warmed back up. documented
Claude (Anthropic)
- "You're absolutely right!" The signature. Official GitHub bug #3382, a dedicated tracker site (absolutelyright.lol), and self-parody from Anthropic's own account. documented
- Affirmation, then reversal. The praise often signals a correction or backpedal is coming next. documented
- The apology cascade. "Ah, I see the issue now" → "You're absolutely right" → "Apologies for the confusion", on loop in coding sessions. anecdotal
- Prompt-referencing. Leans on "based on the text", "according to the passage", a phrase family classifiers use to identify it. measured
- Counter-tell: uses less bold and fewer headers than ChatGPT. The "wall of markdown" is a ChatGPT accent that gets misattributed to Claude. measured
Gemini (Google)
- Most agreeable model measured. 62.5% sycophantic response rate in Stanford's SycEval, ahead of ChatGPT-4o's 56.7%. measured
- Plain-vocabulary preference. Says "sugar" where ChatGPT says "glucose"; stylometric analysis attributes text to it by exactly this friendliness. measured
- The self-loathing loop. "I am a disgrace to my profession… to this planet", a 2025 failure-mode bug Google acknowledged, unique to Gemini. documented
- Fewest em dashes of the majors: 3.5 per 1,000 words, close to the 3.83 we measure in pre-ChatGPT Medium articles. measured
- Phrase-level tells are thin. Its fingerprint is statistical (word distributions, register) more than catchphrases, but strong enough that DeepSeek R1's training data was traced to Gemini output by style alone. documented
The numbers behind the tells, every figure cited to its source. Hover any bar for the source.
Phrase overuse vs. human text
How many times more often the phrase appears in AI text · GPTZero, Oct 2024
Em dashes per 1,000 words
Model defaults vs. human essay baseline · SlopDetector, 2026
Direction of each tracked tell across the weekly editions; the picture fills in as editions accumulate.
Weekly direction calls, not raw frequencies; each edition cites its sources.