sameness

Do the pages of one site look like one template?

Detectors for the AI look score one page at a time: the purple gradient, Inter, three feature cards. But when people are asked what gives a machine-made site away, the two answers at the top are not features. In a Reddit corpus of 3,033 on-topic comments, "screams AI" (6.4%) and "they all look the same" (6.1%) each beat every specific feature; purple, gradients, animations and glass together add up to about 7%. Sameness is a property of a set of pages. sameness compares the pages of one site with each other.

pip install git+https://github.com/tsurutanmen/sameness

No dependencies. Python 3.9 or later.

Thirty seconds

$ sameness tests/fixtures/clone_*.html

4 pages

sameness    1.00   mean similarity of the content skeleton across page pairs (1 = one template)
shells      1      distinct header/nav/footer structures (1 = one site)
palette     1.00   mean overlap of hex colours between pages (1 = one palette)

near-clones (content skeleton >= 90% similar):
  clone_0.html  ~  clone_1.html  ~  clone_2.html  ~  clone_3.html

same meta description on several pages:
    4 page(s)  "One platform to elevate your workflow."

headings that appear on several pages (outside header/nav/footer):
    4x  Ready?

page           words emoji grad   sym  repeated blocks
clone_0.html      36     0    0   3x3  cardx3
...
note: pages share one content skeleton; a reader will see one template with the words swapped
note: 4 pages reuse a meta description; search results will show the same sentence for each

Or crawl a live site, same host only, linked stylesheets included:

sameness --site https://example.com --max 20

What it measures

Everything comes from the markup and the stylesheet text. Nothing is rendered, so layout that only exists after JavaScript runs is not seen.

Two real sites

A 15-page site of ours that had been built in four sittings. No page-level detector complained; the Tell Score was A or B on every page. sameness reported:

sameness    0.26
shells      8      distinct header/nav/footer structures (1 = one site)
palette     0.26
font sets:  5
note: 8 different shells on one site: the pages do not read as one place

That was the finding a reader had already made ("it looks like four different sites"), now as a number. The other direction, a small research site with one shell:

sameness    0.51
shells      1
palette     1.00
near-clones: the six research notes share one article skeleton
same meta description on several pages:  2 page(s)  "aaaaaaaaaaaaaa"

The near-clones are articles and are supposed to look alike. The placeholder description was real and had been missed.

Python

import sameness

pages = [sameness.extract(html, name=url) for url, html in docs]
rep = sameness.compare(pages)
print(rep)
rep.to_dict()                      # everything, JSON-serialisable

for p in rep.pairs:                # pairwise numbers
    print(p.a, p.b, p.skeleton, p.headings, p.classes)

for url, html, css in sameness.crawl("https://example.com", max_pages=20):
    ...

Claude Code skill

skill/sameness/SKILL.md tells Claude Code to run this after building or editing more than one page of a site, and how to read the result. Install by copying the folder:

cp -r skill/sameness ~/.claude/skills/sameness

Related tools

Per-page detectors, which this complements rather than replaces: ai-design-tells (Tell Score, 27 tells), avoid-ai-design (a rewrite skill), vibecoded-audit (49 tells, crawls but scores per page). The Reddit corpus is from vibecoded-design-tells.

License

MIT.