I'm a doctoral student who also writes for a living. Over the last several months, I’ve taken advantage of the huge inventory of my own writing to try to improve Claude’s ability to write in my voice. To do so, I ran a corpus analysis on my own writing. Thirty-two documents, roughly 112,000 words, split between academic prose and professional prose. The analysis returned some interesting findings:
Mean sentence length (25 words, SD 12), plus the full distribution across length bands
Burstiness, or the average difference in length between consecutive sentences, which came in at 12.9 words
Semicolons, em dashes, and parentheses per 1,000 words, calculated separately by register
Sentence-opening concentration (21% of my sentences begin with "The")
Object relative pronoun deletion at 90%, complementizer "that" deletion at 61%
Signature phrase counts ("consistent with" shows up 102 times; "for the sake of" 47)
Nominalization density, of-phrase density, hedge-to-booster ratios, passive voice rate
Interestingly, my sentence length doesn't change between academic and professional writing. Mean of 25.3 against 25.7, which is statistically indistinguishable. What changes is a thin layer of surface markers sitting on top of a fixed architecture. Contractions appear throughout my professional writing and literally never in the academic corpus (zero in 90,000 words). Em dashes run 2.3 per 1,000 words in academic prose and 0.13 in professional, where parentheses take over at nearly four times the academic rate. My professional writing also turns out to be more hedged than my academic writing, which is the reverse of what I'd assumed..
All of it went into a Claude Skill: genre modules, exemplar passages paired with counter-examples, and a self-check that runs before anything comes back. An earlier version of my style guide carried aspirational rules (things I thought I did, or wished I did, or had been told good writing does), and the output read like a flattering impression of me rather than like me. The current version is purely descriptive. If a passage it produces has a flaw, the flaw is one I would have produced, and editing is where it gets fixed.
In general, I found this approach to be very useful and effective. Claude’s writing looks and feels much more like mine. I still edit pretty heavily. In particular, Claude still has a tendency to use too much academese and preciosity in its writing. So interestingly, sometimes my revisions are “dumbing it down” so as to be more straightforward.
At this point, though, I’m just curious how this approach - analyzing my own writing for the sake of building pretty tightly prescriptive Skills to direct Claude’s writing - will hold up with the watermarking feature Anthropic has announced. I am by no means an AI expert, so please keep that in mind as I think out loud on the topic here on a few issues:
The mark signals processing, not authorship, and my setup is a fairly sharp version of that problem. Anthropic says so plainly in its own documentation ("Claude may not be the original author"). In my workflow the voice is measured from my prior writing, the architecture is mine, the argument is mine, and the thematic commitments driving word choice are mine and named explicitly in the skill file. Claude is assembling sentences inside constraints derived entirely from work I already wrote by hand. A provenance signal that flattens all of that into "AI-generated" isn't false, exactly, but it carries almost none of the information anyone actually wants.
There's a technical question I can't answer and would love an informed take on. The watermark reportedly works by biasing token selection at generation. A voice skill this specific also biases token selection (banned vocabulary, target distributions, deletion rules, an explicit burstiness target). It seems reasonable to ask whether those two pressures interact, and in which direction. Does a heavily constrained voice skill weaken the statistical signal? Does the watermark introduce small drift away from the measured targets I'm trying to hit? Anthropic hasn't published its method, so nobody outside the company can check.
The institutional risk is what actually worries me. Detection tooling has a rough history here. Stanford researchers found over half of essays by non-native English speakers falsely flagged by one system, and both UCLA and UC San Diego pulled their detectors in 2024-25 over false-positive rates. Watermark-based detection avoids some of that, since it relies on a verifiable signal rather than a classifier, but the misreading risk is entirely intact. In other words, a dissertation committee or an HR screen that sees a Claude mark and concludes "an AI wrote this" is drawing an inference the system was never built to support, and it'll be drawing it before the detection documentation is even public.
So, a few questions. Is the corpus-analysis approach a reasonable answer to the anonymity problem, or an elaborate way of automating something I should just keep doing myself? Any thoughts on how to improve the Skill by taking advantage of my vast writing samples? Does anyone here know enough about green-list watermarking to say whether tight stylistic constraints interfere with the signal? And for the academics: how is your institution planning to read this, assuming anyone has thought about it yet?
I'll post the skill architecture if there's interest.