v1.6.0

Added

• ai-tells-experimental: New opt-in style with 13 rules for detecting
  structural AI writing patterns that Vale's regex-based rules can't catch.
  Uses Tengo scripts, metric formulas, capitalization, and substitution
  check types to analyze document-level properties. Shipped as a separate
  ai-tells-experimental.zip release artifact (includes config/scripts/).
  All rules at warning level; thresholds are research-grounded starting
  points pending calibration on a larger corpus.
• SentenceLengthVariance (script): Flags sections where the coefficient
  of variation of sentence word counts falls below 0.30. Gibbs (2024):
  ChatGPT averages ~27 words/sentence with low variance; PNAS (2025):
  instruction-tuned LLMs compress the sentence-length range humans produce
• ParagraphLengthVariance (script): Flags sections where paragraph-length
  CV falls below 0.25. Pangram Labs (2025): AI paragraphs default to uniform
  60-100 word blocks
• SentenceStartRepetition (script): Flags sections where >30% of
  sentences start with the same word (minimum 6 sentences, 3 occurrences).
  Complements StackedAnaphora for non-consecutive repetition
• SentenceStartEntropy (script): Measures Shannon entropy of sentence-
  starting words per section. Flags when normalized entropy falls below 0.65,
  catching low diversity even when no single opener dominates
• ContentDuplication (script): Detects near-identical paragraphs within
  a section using Jaccard word-overlap similarity. Flags the later occurrence
  when two paragraphs share more than 60% of their words
• ContractionAvoidance (script): Detects documents that avoid
  contractions despite using informal language. Two-pass approach: informality
  gate (pronouns, questions) then ratio check. PNAS (2025): GPT models use
  contractions at 60-63% of the human rate
• TransitionRepetition (script): Flags when the same formal transition
  phrase appears 3+ times within a section. Tracks 20 common transitions
  including "moreover," "furthermore," "additionally," "hence," "thus"
• TricolonDensityDocument (script): Detects when tricolons make up >60%
  of all enumerated lists in a document with at least 4 tricolons and 20%
  sentence density. Gorrie (2024), tropes.fyi: tricolon overuse is a key AI
  rhetorical tell
• AverageSentenceLength (metric): Flags documents where
  words / sentences > 25.0
• LongWordDensity (metric): Flags documents where
  long_words / words > 0.4. PNAS (2025): mean word length is a top-5
  discriminating feature between AI and human text
• ComplexWordDensity (metric): Flags documents where
  complex_words / words > 0.3. PNAS (2025): nominalizations appear at
  150-214% of human rates in GPT output
• HeadingTitleCase (capitalization): Flags markdown headings using Title
  Case. Wikipedia: "AI chatbots strongly tend to capitalize all main words
  in section headings." Supports project-specific exceptions via Vale vocab
• VocabularySwap (substitution): Inline rewrite suggestions for 20 AI
  vocabulary words (56 swap entries covering inflected forms). Complements
  OverusedVocabulary by suggesting concrete alternatives

Changed

• Release workflow: ai-tells-experimental.zip now ships as its own
  release artifact alongside ai-tells.zip and ai-tells-commits.zip

Fixed

• SentenceStartRepetition: Fixed integer division that caused the rule
  to fire only at 100% repetition instead of the intended 30% threshold
• ContractionAvoidance: Fixed integer division that caused false
  positives on every document with full forms regardless of contraction count.
  Added 9 missing contraction/full-form pairs (you'll, you've, she's, he's,
  there's, here's, what's, who's, let's)
• TransitionRepetition: Fixed substring matching that counted "thus"
  inside "enthusiasm" and "hence" inside "whence". Now uses word-boundary
  matching
• SentenceLengthVariance, SentenceStartRepetition: Fixed section
  variable overwriting that broke position lookups (all matches pointed to
  position 0)
• ParagraphLengthVariance: Fixed code-block toggle tracking that got
  permanently stuck, skipping all content after the first fenced block.
  Now strips code blocks with regex before paragraph splitting
• Script rule messages: Removed %s placeholders from 4 script rule
  messages that dumped the entire matched text span instead of metric values
• Section splitting: All 7 section-splitting scripts now handle headings
  at the start of a document (previously required a leading newline)

Full Changelog: v1.5.1...v1.6.0