Why the warning fires with no matching config
Astro validates markdown.gfm and markdown.smartypants against a project’s config to print this deprecation warning only when a reader actually set one of them. The Container API’s AstroContainer.create() and createFromManifest() methods broke that check. They passed Astro’s internal ASTRO_CONFIG_DEFAULTS, which already sets gfm: true and smartypants: true as baseline defaults, straight into the same validation function normal builds use.
The validator can’t tell a default value from a value a reader actually typed into astro.config.mjs. Every Container API render saw gfm: true and treated it as user-set, so the warning fired unconditionally. Issue #17206, opened 2026-06-26 against astro@7.0.3, reproduces this with the Container API rendering MDX content.
A real bug, not a hint to change your config
Nothing about this warning pointed at an actual problem. It fired identically
whether a project set gfm/smartypants or left them untouched, which is
exactly what made it confusing to debug: there was no config change that made
it stop.
Is this still a problem on Astro 7 today?
No. PR #17261 fixed it, merged 2026-07-01, shipped in astro@7.0.6. The fix strips gfm and smartypants out of the defaults object before it reaches the validator, so the Container API now validates a reader’s raw config the same way a normal build already did.
[astro] `markdown.gfm` and `markdown.smartypants` are deprecated. Move them
onto your processor instead (e.g. `satteri({ features: { gfm: false,
smartPunctuation: false } })`, or `unified({ gfm: false, smartypants: false })`
from `@astrojs/markdown-remark`). Will be removed in a future major.There’s no config change to make on your end. Updating astro to 7.0.6 or later removes the false positive completely.
npm install astro@latestConfirmed version range
This site runs astro@^7.1.3, well past the 7.0.6 fix, and doesn’t use the Container API anywhere in its own source, so it never hit this specific warning. If you’re rendering MDX through AstroContainer and see this exact message on astro@7.0.3 through 7.0.5, it’s this bug, not a real deprecation to act on. Anyone genuinely migrating markdown.gfm/markdown.smartypants off deprecated top-level keys should follow the markdown.rehypePlugins deprecation fix instead, which covers the real version of this migration.
Browse more fixes from this same upgrade in the Guides & Fixes archive.
