AI crawlers (GPTBot, ClaudeBot, PerplexityBot)
AI crawlers are the automated programs that fetch web pages for AI systems. The main ones for shopping are OpenAI's GPTBot, OAI-SearchBot, and ChatGPT-User; Anthropic's ClaudeBot; and PerplexityBot. Most of them read your raw HTML and do not run JavaScript.
How it works
An AI crawler requests your page and takes what the server returns. Vercel's analysis of AI crawler logs found the major crawlers fetch JavaScript files without executing them, with Google's Gemini the exception because it uses Googlebot's renderer. So whatever is missing from the raw HTML is missing from your product as far as the crawler is concerned.
A commerce example
If your price and availability only appear after JavaScript builds the page in a shopper's browser, a crawler reading the raw HTML sees a page with no usable product data, and you drop out of the comparison.
What this means for your store
Serve your product data as plain HTML, and make sure you are not accidentally blocking these crawlers in your robots.txt or firewall.