---
title: "Is llms.txt universal among design systems?"
description: "No: 14 of 19 publish one, and it is not what separates the leaders."
url: "https://state-of-ai-in-design-systems.netlify.app/questions/llms-txt-adoption.md"
canonical: "https://state-of-ai-in-design-systems.netlify.app/questions/llms-txt-adoption.md"
type: "question"
id: "llms-txt-adoption"
data_collected: "2026-07-26/27"
generated: "2026-07-28T06:01:02Z"
report: "State of AI in Design Systems — July 2026"
author: "Kaelig Deloumeau-Prigent"
license: "CC-BY-4.0"
citation: "Deloumeau-Prigent, K. (2026). State of AI in Design Systems. https://state-of-ai-in-design-systems.netlify.app/questions/llms-txt-adoption.md"
---

> Snapshot of 2026-07-27. Every claim below links to the source URL it was taken from. Check the source before citing.

# Is llms.txt universal among design systems?

No — 14 of 19 publish one, and 5 do not:
[Primer](https://state-of-ai-in-design-systems.netlify.app/systems/primer-github.md), [Salesforce Lightning Design System](https://state-of-ai-in-design-systems.netlify.app/systems/salesforce-slds.md), [Shopify Polaris](https://state-of-ai-in-design-systems.netlify.app/systems/shopify-polaris.md), [Microsoft Fluent UI](https://state-of-ai-in-design-systems.netlify.app/systems/fluent-ui-microsoft.md), [U.S. Web Design System (USWDS)](https://state-of-ai-in-design-systems.netlify.app/systems/uswds.md).

It is the most common single affordance after the MCP server, and it is not a tiebreaker: several
of the systems without one rate ai-native because they invested in tool surfaces instead. Where
llms.txt does exist, the interesting work is in slicing it by concern or by platform so a model can
load a part instead of the whole. See the curated-context category
(21 techniques) at https://state-of-ai-in-design-systems.netlify.app/techniques/curated-context.md.


Other questions this report answers, and the index of every file: https://state-of-ai-in-design-systems.netlify.app/llms.txt

---

Generated 2026-07-28T06:01:02Z from the State of AI in Design Systems — July 2026 dataset. Index of every machine-readable file: https://state-of-ai-in-design-systems.netlify.app/llms.txt. JSON, SQLite and the MCP endpoint: https://state-of-ai-in-design-systems.netlify.app/ai.md. Kaelig Deloumeau-Prigent, CC BY 4.0.