I was reading the reddit thread on Claude AI crawlers effectively DDOSing Linux Mint forums https://libreddit.lunar.icu/r/linux/comments/1ceco4f/claude_ai_name_and_shame/

and I wanted to block all ai crawlers from my selfhosted stuff.

I don't trust crawlers to respect the Robots.txt but you can get one here: https://darkvisitors.com/

Since I use Caddy as a Server, I generated a directive that blocks them based on their useragent. The content of the regex basically comes from darkvisitors.

Sidenote - there is a module for blocking crawlers as well, but it seemed overkill for me https://github.com/Xumeiquer/nobots

For anybody who is interested, here is the block_ai_crawlers.conf I wrote.

(blockAiCrawlers) {
  @blockAiCrawlers {
    header_regexp User-Agent "(?i)(Bytespider|CCBot|Diffbot|FacebookBot|Google-Extended|GPTBot|omgili|anthropic-ai|Claude-Web|ClaudeBot|cohere-ai)"
  }
  handle @blockAiCrawlers {
    abort
  }
}

# Usage:
# 1. Place this file next to your Caddyfile
# 2. Edit your Caddyfile as in the example below
#
# ```
# import block_ai_crawlers.conf
#
# www.mywebsite.com {
#   import blockAiCrawlers
#   reverse_proxy * localhost:3000
# }
# ```