Salesforce Lightning Design System (SLDS)

SLDS shares ninth place with Microsoft Fluent 2, two places it lost when Salesforce retired its agent server. Its kit is built for one platform, so the first thing to settle is whether you build on Salesforce; if not, the score matters little. The ratings rest on Salesforce’s packages, its developer portal and its GitHub organizations; Salesforce is not a Simbolik partner.

The first 4 signs make the score out of 8: 2 points for a Yes, 1 for a Partly, none for a No. Typed props are rated beside them and left out of the score.

• Design tokens: Yes, 2 points. @salesforce-ux/design-tokens 4.1.0 ships raw and flat JSON, with CSS, Swift and Kotlin beside it. Not in the W3C format, and under a license of its own. Proof: the files of @salesforce-ux/design-tokens 4.1.0 (opens in a new tab), checked November 8, 2026.
• Agent access: No, 0 points. The Salesforce DX MCP server, @salesforce/mcp, held the SLDS tools until Salesforce retired it on November 2, 2026; its npm package is now marked deprecated. Salesforce ships this tooling as skills instead, and skills count under Guidance here, not as an agent connection. Proof: the server’s end-of-life notice (opens in a new tab), checked November 11, 2026.
• Docs: Partly, 1 point. The SLDS site answers 404 for llms.txt and llms-full.txt. Salesforce’s developer portal has official llms.txt files, and its list for Lightning Web Components covers the SLDS styling hooks (the CSS variables SLDS exposes), design tokens and blueprints as Markdown pages. Proof: Salesforce’s llms-lwc.txt (opens in a new tab), checked November 8, 2026.
• Guidance: Yes, 2 points. The official starter kits carry an AGENTS.md aimed at building interfaces with SLDS, a CLAUDE.md and SLDS skills to apply, validate and migrate to SLDS 2, and the SLDS site’s own AI Development Skills page sets out the same three. Proof: SLDS starter kit for Lightning Web Components (opens in a new tab) and AI Development Skills (opens in a new tab), checked November 11, 2026.
• Typed props: Partly, not scored. SLDS itself is CSS and HTML blueprints. The Lightning base components document their attributes, methods and events, while @salesforce/design-system-react ships no types. Proof: Salesforce’s llms-lightning-base-components.txt (opens in a new tab), checked November 8, 2026.

Teams building Lightning Web Components on the Salesforce platform. They get design tokens, a linter and skills from Salesforce itself, provided they send agents to the developer portal for docs rather than to the SLDS site.

• Licenses. The CSS package is BSD-3-Clause, the token package has its own terms, the old main repository was archived in June 2026, and the starter kits and linter are Apache-2.0.
• No server to build on. The retired MCP server’s last version still runs, pinned, but gets no fixes. Build on the skills instead, which Salesforce says will change often.

Two gaps, 3 points. The readable files exist; they are on another Salesforce site. An llms.txt at the root of lightningdesignsystem.com, linking the Markdown pages already on the portal, would earn 1 back. The other 2 need an agent connection from Salesforce again, an MCP server or its equal. For your own agents today, put the portal’s llms-lwc.txt address in your AGENTS.md so they never try the SLDS site first, and install the SLDS skills. Docs AI agents can read explains the rule behind the Docs point, and the best AI-ready design systems, ranked show it beside Fluent 2, the other 5-point system.