SERP Title Width MCP server

mcp-server-serp-title-width

Check whether Chinese, Japanese and Korean page titles fit in Google search results, measured by rendered pixel width instead of character count. Ships as an MCP server (for AI agents) and a CLI (for builds and CI).

Documentation and background: adsandcode.com/en/open-source/serp-title-width

The problem

Site auditors and SEO plugins usually judge title length by counting characters, with limits around 60. That rule of thumb comes from Latin text. In the font Google uses for result titles, a CJK ideograph, a kana or a Hangul syllable is 22px wide, roughly twice an average Latin letter. Sixty of them come to 1320px, about twice the 652px desktop result column. A character-count check passes CJK titles that Google will cut in half.

Google says only that the title link is truncated as needed; its documentation gives no length in characters or pixels:

"the title link is truncated in Google Search results as needed"

(Google Search Central, "Influencing your title links in search results")

So the width has to be measured.

The model

Measured on 2026-09-18 on google.com with the zh-TW (Traditional Chinese, Taiwan) interface, Chrome on Windows, by reading the computed style of a result title and measuring glyph advances with a canvas in the same page.

Thresholds:

A digit costs about 0.56 of a full-width character, so "2026" takes the space of 2.2 ideographs. Capital letters are much wider than digits: an all-caps product name can push a title over the line that a character count, or a model that treats every Latin letter alike, says it fits.

The ASCII widths come from the font file (Arial Version 7.01 on Windows), in font units, measured with scripts/measure-arial.py and cross-checked three ways: Pillow at 2048px, the font's advance-width table read with fontTools, and measureText() on a Chrome canvas set to 22px arial. All 95 agree to within 0.0001px.

Re-measuring

If Google changes the title font size, every number above is wrong. Open a google.com results page in the interface language you care about and run this in the browser console:

Shortened. The full README is on GitHub.