Claude Opus 5.5 writes 'this matters' 116 times as often as human writers, Graphite finds
Graphite counted 13,000 phrases that AI models use at least twice as often as human writers, with a different set for every model version. Editors cleaning AI drafts need a phrase list tied to the model that wrote them, rebuilt at each release.
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What happened
- Opus 5.5 writes 'why X matters' 92 times as often as the human-written samples Graphite compared it against.
- OpenAI's Astra uses corrective framing such as 'not simply X' and 'rather than relying on X' more than 100 times as often as human writers, according to Graphite.
- Labs have cut em dashes: Astra now uses them 88% less than human writers, and Gemini 3.1 Pro has almost dropped them entirely.
- Graphite used 10,000 articles published before ChatGPT's release as its human baseline and had each AI model rewrite them from summaries.
Why it matters
- Who has to decide decision A phrase checklist holds only for the model version it was measured on, so teams publishing AI-assisted copy need a record of which version drafted each piece.
- What it costs cost Whoever owns the house style pays again at each model release, since Graphite finds old tells disappearing while new ones keep the total roughly level.
- What it limits constraint Opus 5.5 overstates and Astra hedges, so one shared edit pass for AI copy cannot correct both models' drafts in the same direction.
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Give Claude Opus 5.5 and OpenAI's Astra the same brief and, going by Graphite's counts, the editor gets back two different cleanup jobs. The Opus draft qualifies its claims less often and is far more likely to use superlatives [6]. It has dropped "it's not X, it's Y" and now writes that something "is more than an X, it's a Y" [14]. The Astra draft hedges, saying an action "may provide" or "can provide" a benefit, and finds "another dimension" in whatever it covers [7].
The labs describe their writing upgrades in general terms. Anthropic said Opus 5.5 "communicates more naturally than prior models" [18]. OpenAI told users of the GPT-6 versions of Sol and Luna to expect more clarity, less jargon and fewer odd turns of phrase [19]. A team reading those release notes could fairly assume its existing checks for AI copy still hold. Graphite measured something narrower. The famous tell did go: Opus 5.5 uses em dashes 99% less often than Opus 5 [8]. The total number of tells held mostly steady anyway, according to Graphite [12]. "They are managing to remove the most well-known tells, but other ones pop up. And every model version has its own," Greg Druck, Graphite's chief AI officer, told TechCrunch [11].
The labs are also moving in different directions. "It turns out that Claude models are actually getting closer to the human word distribution over time," Druck said. "And for the GPT models, it's getting further away." [10] He doubts any lab can finish the job. "These are giant models with billions of parameters. They have some finite number of tests they can run, and things slip through," he said [23].
Treat the exact multiples as approximate. Graphite is a marketing company, and Gizmodo advised taking its study "with a grain of salt" [1]. Gizmodo puts "dependable" at 26 times the human rate and calls "this matters" the biggest single tell [21][5]. TechCrunch has "dependable" at 23 times and names it Opus 5.5's biggest tell [22]. Astra's 275x figure for "does not establish" is measured against Claude's output, not against human writing [16]. Every ratio comes from the one rewriting task in Graphite's design [17]. Gizmodo describes an AI-detector business "somehow worth millions of dollars" [24]; neither report says how those detectors score against the newer phrases.
At a 2x threshold the list runs to 13,000 entries [2], far more than an editor can check by hand. The usable part is the short head of the list for one model version. For Opus 5.5, I'd check "this matters," "why X matters," "looking ahead the" and "is more than an X, it's a Y" [3][4][13][14]. For Astra, the list starts with "not simply," "rather than relying on" and "may provide" [15][7]. I'd keep a list like that for each model in use, knowing it expires at the next release [11] and rests on one firm's single-task study [1][17].
Sort each AI-assisted draft on two things: whether the editor can name the model version that wrote it, and whether the phrase list was built on that version. Two yeses mean the list applies. A named model with an older list catches the previous version's habits, the way an em dash check now finds little in Opus 5.5 output [8]. When nobody can name the model, a per-model list has nothing to match. The edit then falls back on the habit Graphite found across models, contrast-heavy constructions [20], plus a read for whether claims are overstated or over-hedged [6].
What to watch
- Whether Graphite publishes its per-model ratios in full, settling the 23x versus 26x gap on 'dependable'.
- The next Opus and Astra releases, and whether 'this matters' and corrective framing fall away the way em dashes did.
- Any published test of commercial AI detectors against the newer per-model phrases.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence45
- Adoption
- Not scored
- Hype gap+25
- Incentives55
- Confidence50
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
Graphite, a marketing company, identified about 13,000 words and phrases it believes are likely indicators of AI-produced text; Gizmodo advised taking the study 'with a grain of salt'.
- [2]
Graphite found 13,000 phrases that were at least twice as common in AI content as in human content, its definition of a 'tell'.
- [3]
Claude Opus 5.5 uses the phrase 'this matters' 116 times more often than human writing.
- [4]
In Opus 5.5 output, 'why X matters' occurs 92 times more often than in human writing.
- [5]
According to Graphite, the biggest single tell is the phrase 'this matters'.
- [6]
Opus 5.5 qualifies claims less often than Astra does and is far more likely to use superlatives.
- [7]
OpenAI's Astra likes to describe 'another dimension' of its topic and hedges claims by saying an action 'may provide' or 'can provide' a benefit.
- [8]
In Graphite's samples, Opus 5.5 used em dashes 99% less often than Opus 5.
- [9]
Astra uses em dashes 88 percent less than human samples, and Gemini 3.1 Pro has almost completely eliminated the em dash from its writing.
- [10]
It turns out that Claude models are actually getting closer to the human word distribution over time. And for the GPT models, it's getting further away.
- [11]
It's not like the tells are decreasing. They are managing to remove the most well-known tells, but other ones pop up. And every model version has its own.
- [12]
While individual tells change, Graphite says the overall number of tells is mostly holding steady.
- [13]
The phrase 'looking ahead the' appears in Claude outputs 40 times more frequently than in human material.
- [14]
Opus 5.5 now avoids the 'it's not X, it's Y' construction but still tends to say something 'is more than an X, it's a Y.'
- [15]
Astra's biggest tell is corrective framing such as 'not simply X' or 'rather than relying on X'; these constructions were more than 100 times more common in Astra prose than in human writing.
- [16]
The phrase 'does not establish' is 275 times more common in Astra text than in Claude's outputs.
- [17]
Graphite used a corpus of 10,000 articles published before ChatGPT's release as the human control group, then had AI models rewrite the articles from summaries.
- [18]
In the Opus 5.5 release, Anthropic said the model 'communicates more naturally than prior models' and that early users 'found its writing clearer and easier to follow.'
- [19]
Releasing the GPT-6 versions of Sol and Luna, OpenAI said users could 'expect to see more clarity, less jargon, [and] fewer odd turns of phrase.'
- [20]
Models still fall back on contrast-heavy constructions, with each model version showing its own quirks.
- [21]
Claude uses the word 'dependable' 26 times as much as human counterparts.
- [22]
Claude Opus 5.5's biggest tell is the word 'dependable', which appears 23 times more often than in human samples.
- [23]
A general hypothesis I have is that the labs are less able to control some of these things than you might expect. These are giant models with billions of parameters. They have some finite number of tests they can run, and things slip through.
- [24]
A micro-economy of AI detectors has cropped up and is 'somehow worth millions of dollars.'
Sources
2 independent publishers whose own reporting we read for this story.
- gizmodo.com‘This Matters’: Researchers Identify Thousands of New Tells in AI Writing
1 article · October 2, 2026
- techcrunch.comOpus 5.5 loves to tell you ‘this matters’ (and other AI writing tells)
1 article · October 1, 2026
Topics and entities
Topics
- AI Text Detection
- LLM writing style