When agents inline JSON in curl -d '...' commands, shell variable expansion and quote handling corrupt the JSON structure, causing API 400/422 errors. ## Agent Decision Tree 1. Are you using curl -d '{...}' with inline JSON? → go to Solution A 2. Does the JSON contain $, backticks, or nested quotes? → definitely go to Solution A 3. Getting 400/422 from the API? → check if the JSON arrived intact