Nope, you should send HTTP header 'SPbCTF' with value "Pretty cool"

Current HTTP headers: Array
(
    [Host] => kslweb1.spb.ctf.su
    [Connection] => close
    [accept] => */*
    [user-agent] => Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
    [referer] => http://kslweb1.spb.ctf.su/first/level6
)