--- title: "Starlight: vendor profile: Agent Ready HTML" description: "Starlight, a framework: 2 of 6 standards stated as supported, 14 sourced facts, dated plans and what it does not do. Read 2026-11-05." canonical: https://agentreadyhtml.com/vendors/starlight/ site: "Agent Ready HTML" last_updated: 2026-11-05 section: "Vendors" --- # Starlight: vendor profile: Agent Ready HTML > Starlight, a framework: 2 of 6 standards stated as supported, 14 sourced facts, dated plans and what it does not do. Read 2026-11-05. Source: https://agentreadyhtml.com/vendors/starlight/ Site: Agent Ready HTML Last reviewed: 2026-11-05 # Starlight: vendor profile In short A default Starlight 0.42.9 build kept its home H1 in the server HTML and wrote a 404.html, but no llms.txt or robots.txt. With no site value set, the sitemap was skipped. Community plugins supply llms.txt and JSON-LD, and Pagefind provides search. The Astro Technology Company, which builds Astro under it, joined Cloudflare on 2026-01-16. ## At a glance **standards.txt** starlight ```text llms-txt = partial markdown-negotiation = no statement markdown-twin = partial initial-html = supports real-404 = supports vary-accept = no statement ``` 2 supports, 2 partial or announced, 2 no statement. **Starlight** Framework Astro's documentation framework that pre-renders pages to static HTML with a built-in 404 page and Pagefind search; sitemap needs the Astro site URL, and llms.txt, .md.txt twins and JSON-LD come from community plugins. Type [Framework](https://agentreadyhtml.com/vendors/by-type/framework/) Operator, as the facts below state it The Astro Technology Company (part of Cloudflare since January 2026) Home page [starlight.astro.build](https://starlight.astro.build/), answered HTTP 200 on 2026-11-05 Last read 5 November 2026 ## What it does for this layer - Starlight's prerender option defaults to true, so pages are built as static HTML; prerender: false hands them to an SSR adapter instead. \[primary source\] [source](https://starlight.astro.build/reference/configuration/), read 5 November 2026. - Starlight injects a default 404 page; disable404Route: true turns that off so a project can ship its own src/pages/404.astro. \[primary source\] [source](https://starlight.astro.build/reference/configuration/), read 5 November 2026. - Search in Starlight is Pagefind with no setup step; a page drops out of the index with pagefind: false in its frontmatter. \[primary source\] [source](https://starlight.astro.build/guides/site-search/), read 5 November 2026. - Starlight's plugins page lists starlight-llms-txt, a community plugin that adds llms.txt following llmstxt.org. \[primary source\] [source](https://starlight.astro.build/resources/plugins/), read 5 November 2026. - The same Starlight plugins list carries starlight-md-txt, which exposes each page as raw Markdown at a .md.txt URL. \[primary source\] [source](https://starlight.astro.build/resources/plugins/), read 5 November 2026. - For structured data the Starlight plugins list points to starlight-seo, a community plugin that adds a connected JSON-LD graph and a build-time SEO audit. \[primary source\] [source](https://starlight.astro.build/resources/plugins/), read 5 November 2026. - The starlight-llms-txt plugin site says the plugin generates llms.txt, llms-full.txt and llms-small.txt for a Starlight site. \[secondary source\] [source](https://delucis.github.io/starlight-llms-txt/), read 5 November 2026. - starlight.astro.build itself returned 404 for /llms.txt and /robots.txt on 2026-11-05, while /sitemap-index.xml answered 200. \[observed\] [source](https://starlight.astro.build/guides/customization/), read 5 November 2026. - GitHub lists @astrojs/starlight 0.42.9 as released on 2026-11-04 by the astrobot-houston account. \[primary source, 2026-11-04\] [source](https://github.com/withastro/starlight/releases/tag/%40astrojs/starlight%400.42.9), read 5 November 2026. - The Astro Technology Company, which builds the Astro framework under Starlight, joined Cloudflare on 2026-01-16 and says Astro stays open source and MIT licensed. \[primary source, 2026-01-16\] [source](https://astro.build/blog/joining-cloudflare/), read 5 November 2026. - Starlight's getting started page scaffolds a project with npm create astro@latest -- --template starlight. \[primary source\] [source](https://starlight.astro.build/getting-started/), read 5 November 2026. ## Test build - A default Starlight project (npm create astro@5.3.1 -- starlight-test --template starlight --install --no-git --yes --skip-houston; npm run build) with @astrojs/starlight 0.42.9 and astro 7.4.1 skipped the sitemap on 2026-11-05 because site was unset. \[observed\] [source](https://starlight.astro.build/getting-started/), read 5 November 2026. - The Starlight 0.42.9 build output held 404.html, a pagefind index and the pages, with no llms.txt or robots.txt; the home H1 'Welcome to Starlight' was in the server HTML. \[observed\] [source](https://starlight.astro.build/getting-started/), read 5 November 2026. - Under astro preview a request for / sending only Accept: text/markdown got 404 text/html instead of the home page, a preview server quirk worth knowing before testing negotiation locally. \[observed\] [source](https://starlight.astro.build/getting-started/), read 5 November 2026. ## Products and plans | Product | What it is | Price | As of | Source | | --- | --- | --- | --- | --- | | Starlight (@astrojs/starlight) | Astro integration that turns a content folder into a documentation site. | Free, open source; MIT licence, free; version 0.42.9 on 2026-11-04 | 2026-11-05 | source | ## Standards | Standard | Status | What the vendor's pages say | Source | | --- | --- | --- | --- | | llms-txt | partial | Starlight's own plugins page lists the community plugin starlight-llms-txt for llms.txt; core Starlight writes none. | source | | markdown-negotiation | no statement | No statement found in the Starlight configuration reference, customization guide or plugins list; starlight.astro.build returned HTML to Accept: text/markdown. | none | | markdown-twin | partial | The community plugin starlight-md-txt, listed by Starlight, exposes pages as Markdown at .md.txt URLs. | source | | initial-html | supports | Starlight pages are pre-rendered by default (prerender defaults to true). | source | | real-404 | supports | Starlight injects a default 404 page unless disable404Route is set, and astro preview returned 404 for a made-up path. | source | | vary-accept | no statement | No statement found in the Starlight configuration reference or site search guide; Starlight does not negotiate on Accept. | none | ## Checks on its own site | Reading | Result | Date | | --- | --- | --- | | Home page request | HTTP 200; H1 in the initial HTML: yes; 537 words; 0 JSON-LD blocks | 2026-11-05 | | Request with Accept: text/markdown | HTTP 200, text/html, Vary: Accept-Encoding | 2026-11-05 | | /llms.txt at the host root | HTTP 404, text/html, 21 KB | 2026-11-05 | | A made-up path | HTTP 404 | 2026-11-05 | | Ora score, cached | 37, grade D | 2026-11-03 | | Cloudflare keyless scan | 7, L0 Not Ready | 2026-11-05 | ## What it does not do - Without site set in astro.config.mjs a Starlight build silently skips sitemap generation, as the 0.42.9 test build showed. [source](https://starlight.astro.build/guides/customization/), read 5 November 2026. ## Related pages on this site - [Frameworks in this section](https://agentreadyhtml.com/vendors/by-type/framework/) - [The Plain Fetch viewer](https://agentreadyhtml.com/viewer/) ## Sources 1. [Starlight: home page](https://starlight.astro.build/) https://starlight.astro.build/, read 5 November 2026 2. [Configuration Reference | Starlight](https://starlight.astro.build/reference/configuration/) https://starlight.astro.build/reference/configuration/, read 5 November 2026 3. [Customizing Starlight | Starlight](https://starlight.astro.build/guides/customization/) https://starlight.astro.build/guides/customization/, read 5 November 2026 4. [Site Search | Starlight](https://starlight.astro.build/guides/site-search/) https://starlight.astro.build/guides/site-search/, read 5 November 2026 5. [Plugins and Integrations | Starlight](https://starlight.astro.build/resources/plugins/) https://starlight.astro.build/resources/plugins/, read 5 November 2026 6. [starlight-llms-txt documentation](https://delucis.github.io/starlight-llms-txt/) https://delucis.github.io/starlight-llms-txt/, read 5 November 2026 7. [Getting Started | Starlight](https://starlight.astro.build/getting-started/) https://starlight.astro.build/getting-started/, read 5 November 2026 8. [Release @astrojs/starlight@0.42.9 · withastro/starlight · GitHub](https://github.com/withastro/starlight/releases/tag/%40astrojs/starlight%400.42.9) https://github.com/withastro/starlight/releases/tag/%40astrojs/starlight%400.42.9, read 5 November 2026 9. [The Astro Technology Company joins Cloudflare](https://astro.build/blog/joining-cloudflare/) https://astro.build/blog/joining-cloudflare/, read 5 November 2026 10. [Starlight LICENSE](https://raw.githubusercontent.com/withastro/starlight/main/LICENSE) https://raw.githubusercontent.com/withastro/starlight/main/LICENSE, read 5 November 2026 Last reviewed 5 November 2026 Edition Crawl 2026-11-04 Page updated 2026-11-05 Method How the viewer reads a page, how a file is graded and how a platform is scored: [the method page](https://agentreadyhtml.com/method/).