Major Changes

• #16610 c63e7e4 Thanks @matthewp! - Adds background dev server management for AI coding agents.

  When an AI coding agent is detected, astro dev now automatically starts the dev server as a detached background process. This prevents the dev server from blocking the agent's terminal and allows it to continue working while the server runs.

  A lock file (.astro/dev.json) is written when the dev server starts, recording the server's URL, port, and PID. This prevents duplicate servers from being started for the same project.

  New flag and subcommands

  • astro dev --background — Start the dev server as a background process (this is what runs automatically when an agent is detected).
  • astro dev stop — Stop a running background dev server.
  • astro dev status — Check if a dev server is running and display its URL, PID, and uptime.
  • astro dev logs — View logs from a background dev server. Use --follow (-f) to stream new output as it's written.

  These allow you to start and manage dev servers programmatically and were designed with AI coding agents in mind.

  What should I do?

  No action is required. If you are not using an AI coding agent, astro dev behaves exactly as before. If you are using an agent, background mode is enabled automatically — the agent will receive the server URL and PID, and can use astro dev stop to shut it down.

  To opt out of automatic background mode when an agent is detected, set the environment variable ASTRO_DEV_BACKGROUND=0 before running astro dev.

• #16725 10229f7 Thanks @ArmandPhilippot! - Removes deprecated APIs exported from astro:transitions.

  In Astro 6.x, some helpers available in astro:transitions and astro:transitions/client were deprecated.

  In Astro 7.0, the following APIs can no longer be used in your project:

  • TRANSITION_BEFORE_PREPARATION
  • TRANSITION_AFTER_PREPARATION
  • TRANSITION_BEFORE_SWAP
  • TRANSITION_AFTER_SWAP
  • TRANSITION_PAGE_LOAD
  • isTransitionBeforePreparationEvent()
  • isTransitionBeforeSwapEvent()
  • createAnimationScope()

  What should I do?

  Remove any occurrence of createAnimationScope():

  -import { createAnimationScope } from 'astro:transitions';

  Replace any occurrence of the other APIs using the lifecycle event names directly:

  -import {
  -	TRANSITION_AFTER_SWAP,
  -	isTransitionBeforePreparationEvent,
  -} from 'astro:transitions/client';
  
  -console.log(isTransitionBeforePreparationEvent(event));
  +console.log(event.type === 'astro:before-preparation');
  
  -console.log(TRANSITION_AFTER_SWAP);
  +console.log('astro:after-swap');

  Learn more about all utilities available in the View Transitions Router API Reference.

Patch Changes

• #16980 1f07343 Thanks @matthewp! - Removes state.provide(), state.resolve(), state.finalizeAll(), and App.Providers from the public advanced routing API. These context provider extension points are now internal-only. If you were using them in an integration, use locals to share per-request state instead.

• #16982 1e000e2 Thanks @matthewp! - Improves the warning when accessing Astro.session without session storage configured. The session property is now always defined on the context object, and accessing it without configuration logs a helpful message instead of silently returning undefined.

• #16990 ebeb830 Thanks @ocavue! - Fixes Astro.request.url not reflecting validated X-Forwarded-Proto/X-Forwarded-Host headers when security.allowedDomains is configured. Previously, only Astro.url was updated with the forwarded origin while Astro.request.url retained the socket-derived URL, causing the two to diverge behind TLS-terminating proxies.

Minor Changes

• #16549 9d9d516 Thanks @ocavue! - Updates @sveltejs/vite-plugin-svelte to v7. No user action is necessary.

Patch Changes

• #16969 4a31f90 Thanks @Princesseuh! - Adds support for Prism syntax highlighting to the Sätteri Markdown and MDX processors. Setting markdown.syntaxHighlight to 'prism' now highlights your code blocks with Prism.

  // astro.config.mjs
  import { satteri } from '@astrojs/markdown-satteri';
  
  export default defineConfig({
    markdown: {
      processor: satteri(),
      syntaxHighlight: 'prism',
    },
  });

• Updated dependencies [4a31f90]:

  • @astrojs/[email protected]

Minor Changes

• #16969 4a31f90 Thanks @Princesseuh! - Adds support for Prism syntax highlighting to the Sätteri Markdown and MDX processors. Setting markdown.syntaxHighlight to 'prism' now highlights your code blocks with Prism.

  // astro.config.mjs
  import { satteri } from '@astrojs/markdown-satteri';
  
  export default defineConfig({
    markdown: {
      processor: satteri(),
      syntaxHighlight: 'prism',
    },
  });

Patch Changes

• #16990 ebeb830 Thanks @ocavue! - Fixes a build crash when using experimental.advancedRouting with a custom fetchFile that statically imports cf from @astrojs/cloudflare/fetch. The circular dependency between @astrojs/cloudflare/fetch and astro/app/entrypoint caused createApp or createGetEnv to be undefined at module evaluation time. Initialization is now deferred to the first cf() call, breaking the cycle.

• #16671 fd926fd Thanks @alexanderniebuhr! - Removes deprecations warnings added in Astro v6 for Cloudflare specific Astro.locals properties.

• Updated dependencies [1f07343, 1e000e2, c63e7e4, ebeb830, 10229f7]:

  • [email protected]
  • @astrojs/[email protected]

Patch Changes

• #16926 1b39ae8 Thanks @narendraio! - Prevents App.match() from throwing on request paths that contain an invalid percent-sequence.

• #16924 2c0bc94 Thanks @astrobot-houston! - Fixes an issue where editing a client-side component (e.g. with client:idle, client:load, etc.) caused an unnecessary full program reload of the backend during development.

• #16958 2c1d50f Thanks @fkatsuhiro! - Fixes a bug where static file endpoints using getStaticPaths with .html in dynamic param values (e.g. { path: 'file.html' }) would fail with a NoMatchingStaticPathFound error during build. The .html suffix is no longer incorrectly stripped from endpoint route pathnames.

• #16855 c610cda Thanks @astrobot-houston! - Fixes dynamic routes returning 500 "TypeError: Missing parameter" when using domain-based i18n routing in SSR.

• #16946 606c37b Thanks @ematipico! - Fixes Astro.routePattern to preserve original casing of dynamic parameter names from filenames. Previously, a file at src/pages/blog/[postId].astro would return /blog/[postid] for Astro.routePattern due to an internal .toLowerCase() call. It now correctly returns /blog/[postId].

• #16720 16d49b6 Thanks @thomas-callahan-collibra! - Fix an issue where dynamic routes would return the string [object Object] instead of the expected content, in certain runtimes.

• #16703 17390a6 Thanks @henrybrewer00-dotcom! - Fixes styles being stripped when the project root is started with a path whose case differs from the actual filesystem case (e.g. running astro dev from d:\dev\app while the folder on disk is D:\dev\app).

• #16855 c610cda Thanks @astrobot-houston! - Fixes Astro.currentLocale returning the default locale instead of the domain's locale on dynamic routes served from a mapped domain.

Patch Changes

• #16955 9a93d68 Thanks @Princesseuh! - Updates Sätteri processor to v0.8.0. See its changelog for details on bugs fixed and features added.

• Updated dependencies [9a93d68]:

  • @astrojs/[email protected]

Patch Changes

• #16955 9a93d68 Thanks @Princesseuh! - Updates Sätteri processor to v0.8.0. See its changelog for details on bugs fixed and features added.

Patch Changes

• #16900 17a0fbd Thanks @ocavue! - Bumps devalue dependency to v5.8.1

• #16016 0d85e1b Thanks @felmonon! - Fix a false positive in the dev toolbar accessibility audit for anchors with text inside closed <details> elements.

• #16911 79c6c46 Thanks @astrobot-houston! - Fixes a bug where experimental.advancedRouting with astro/hono handlers threw TypeError: Cannot read properties of undefined (reading 'route') for unmatched routes instead of rendering the custom 404 page.

• #16899 239c469 Thanks @matthewp! - Fixes a false "does not call the middleware() handler" warning when using astro() in a custom src/app.ts and the first request is a redirect route.

• #16887 493acdb Thanks @astrobot-houston! - Fixes redirectToDefaultLocale not working after the Advanced Routing refactoring.

• #16908 ef53ab9 Thanks @florian-lefebvre! - Improves optimized fallbacks generation when using the Fonts API by using better metrics for bold variants

Patch Changes

• #16900 17a0fbd Thanks @ocavue! - Bumps devalue dependency to v5.8.1