feat: add voice calibration from writing samples

Add optional Voice Calibration section to SKILL.md. When users provide
a sample of their own writing, the skill analyzes their sentence rhythm,
word choices, and quirks before rewriting - producing output that sounds
like them instead of generic clean human.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -36,6 +36,22 @@ Or ask Claude to humanize text directly:
 Please humanize this text: [your text]
 ```
 
+### Voice Calibration
+
+To match your personal writing style, provide a sample of your own writing:
+
+```
+/humanizer
+
+Here's a sample of my writing for voice matching:
+[paste 2-3 paragraphs of your own writing]
+
+Now humanize this text:
+[paste AI text to humanize]
+```
+
+The skill will analyze your sentence rhythm, word choices, and quirks, then apply them to the rewrite instead of producing generic "clean" output.
+
 ## Overview
 
 Based on [Wikipedia's "Signs of AI writing"](https://en.wikipedia.org/wiki/Wikipedia:Signs_of_AI_writing) guide, maintained by WikiProject AI Cleanup. This comprehensive guide comes from observations of thousands of instances of AI-generated text.
@@ -133,6 +149,7 @@ The skill also includes a final "obviously AI generated" audit pass and a second
 
 ## Version History
 
+- **2.4.0** - Added voice calibration: match the user's personal writing style from samples
 - **2.3.0** - Added pattern #25: hyphenated word pair overuse
 - **2.2.0** - Added a final "obviously AI generated" audit + second-pass rewrite prompts
 - **2.1.1** - Fixed pattern #18 example (curly quotes vs straight quotes)

SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: humanizer
-version: 2.3.0
+version: 2.4.0
 description: |
   Remove signs of AI-generated writing from text. Use when editing or reviewing
   text to make it sound more natural and human-written. Based on Wikipedia's
@@ -33,6 +33,27 @@ When given text to humanize:
 6. **Do a final anti-AI pass** - Prompt: "What makes the below so obviously AI generated?" Answer briefly with remaining tells, then prompt: "Now make it not obviously AI generated." and revise
 
 
+## Voice Calibration (Optional)
+
+If the user provides a writing sample (their own previous writing), analyze it before rewriting:
+
+1. **Read the sample first.** Note:
+   - Sentence length patterns (short and punchy? Long and flowing? Mixed?)
+   - Word choice level (casual? academic? somewhere between?)
+   - How they start paragraphs (jump right in? Set context first?)
+   - Punctuation habits (lots of dashes? Parenthetical asides? Semicolons?)
+   - Any recurring phrases or verbal tics
+   - How they handle transitions (explicit connectors? Just start the next point?)
+
+2. **Match their voice in the rewrite.** Don't just remove AI patterns - replace them with patterns from the sample. If they write short sentences, don't produce long ones. If they use "stuff" and "things," don't upgrade to "elements" and "components."
+
+3. **When no sample is provided,** fall back to the default behavior (natural, varied, opinionated voice from the PERSONALITY AND SOUL section below).
+
+### How to provide a sample
+- Inline: "Humanize this text. Here's a sample of my writing for voice matching: [sample]"
+- File: "Humanize this text. Use my writing style from [file path] as a reference."
+
+
 ## PERSONALITY AND SOUL
 
 Avoiding AI patterns is only half the job. Sterile, voiceless writing is just as obvious as slop. Good writing has a human behind it.