Works with Astro
Astro ships static HTML with your content already rendered, which is the ideal case for the crawler.
Astro, free beta
DraftMine's Website Humanizer rewrites your public Astro pages in the tone you pick, then lets you edit any section from a dashboard and A/B test up to four versions of it. Removing the snippet restores your original text.
Why it helps on Astro
Installing on Astro
Open your shared layout, usually src/layouts/Layout.astro.
Paste the snippet just before the closing </body> tag.
Build and deploy once. Copy changes after that need no rebuild.
Known limits, stated plainly
The crawler reads the HTML your server sends, so Astro pages whose text only appears after the browser fetches it are not processed. Because replacement happens in the visitor's browser after the page loads, it is not guaranteed to change what search-engine crawlers index; treat this as a tool for the people reading your site, not as an SEO tactic. A/B results need an analytics tool you already have in place. Only the public editorial pages you select are processed, and you can pause or remove the snippet at any time.
Other stacks
Free during beta