"llms.txt 擬似応答率" (llms.txt pseudo-response rate): 8.1% of top .jp sites on 9 November 2026, and how it is counted

The llms.txt 擬似応答率 (llms.txt pseudo-response rate) is the share of sites asked for /llms.txt that answered HTTP 200 but had no real llms.txt file, in most cases an HTML page, a "soft 404". In our weekly scan of 9 November 2026 it was 63 of 775 top .jp sites, 8.1%. In the same week 30 sites (3.9%) had a real file.

Published 15 November 2026. Numbers taken on 26 October, 2 November and 9 November 2026. "Pseudo-response rate" (擬似応答率) is our own name for this way of counting, not an industry term. llms.txt is a proposed text file at the root of a site that gives AI apps a short guide to its content; it is a proposal, not a standard.

What is the llms.txt 擬似応答率?

Definition: the llms.txt 擬似応答率 is the share of sites asked for /llms.txt that answered HTTP 200 but had no real llms.txt.
A soft 404 is a server answering 200 with a page for an address that has nothing at it, instead of 404. The page "works"; the thing asked for is not there.
A real llms.txt is an answer that meets all four: HTTP 200; Content-Type text/plain or text/markdown; a body that is not empty and does not open with an HTML tag; and an answer that ends at /llms.txt on the site's own registrable domain.
A pseudo-response is an HTTP 200 answer that does not meet them: a text/html page, an empty body, a redirect to a home page.

How it is counted

llms.txt 擬似応答率 = sites with a pseudo-response ÷ sites we could check

Denominator: sites asked once for /llms.txt, leaving out those whose robots.txt was served by another registrable domain and those whose /llms.txt request ended on another one: 775 to 782 sites per week.
Numerator: among them, sites that answered HTTP 200 and not with a real llms.txt. Other statuses, such as 404, do not count.
Population: the first 1,000 top .jp domains of the Tranco list (a public ranking of the most visited domains). Our scanner identifies itself and asks each site once, every Monday, from a Japanese IP. No site is named.
Counted by status code alone, the week of 26 October 2026 shows 98 sites (12.6%) as having the file: about 3.4 times the 29 real files. The pseudo-response rate makes that gap visible.

The numbers (three weeks)

Scan day	Sites checked	Pseudo-response (llms.txt 擬似応答率)	Real file	Pseudo-responses per real file
2026-10-26	777	69 (8.9%)	29 (3.7%)	2.4
2026-11-02	782	66 (8.4%)	30 (3.8%)	2.2
2026-11-09	775	63 (8.1%)	30 (3.9%)	2.1

All 69 sites of 26 October 2026 answered text/html.
The rate slipped from 8.9% to 8.4% to 8.1%, but three readings do not make a trend.
The real count hardly moved: 29, 30, 30.

Check your own site

Open your-domain/llms.txt in a browser.
Run curl -I https://your-domain/llms.txt and read the status and the Content-Type.
If you have no file and still get 200 and text/html, your site gives a pseudo-response. Change the server or site builder so that unknown addresses return 404.
The free check reads the file itself, not only the status: https://pw.migurei.ai/en/free-scan

Basis and limits

"Pseudo-response rate" is our own name. It is not an industry term, and we do not know whether other surveys count this way.
Top .jp sites only. About 780 of the first 1,000, one list, as seen from our scanner. Other sites may differ.
We do not know why the sites answer 200. We have not looked at their servers.
Our filter does not check syntax. A file served as plain text with wrong contents counts as real; a real file served with an odd Content-Type counts as a pseudo-response.
Whether any AI app reads llms.txt is a separate question; this number does not show it.
Source: the same rows of our weekly published CSV (the "llms.txt present" and "llms.txt answered 200 with something that is not the file" rows): https://pw.migurei.ai/data/japanese-sites-and-ai-bots/2026-W46.csv . Level: observed in our lab.
Next: the scan continues every Monday; the next numbers are those of 16 November 2026.

Three weeks in full, and the gap against counting by status code: llms.txt on top .jp sites: real files and HTML soft 404s
Blog (why we raise this measure): https://migurei.ai/en/blog/llms-txt-pseudo-response-rate
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This page is written by migurei / Parallel World about our own weekly scan. The free check is our own service.