Authorizations
API key for authentication (format: sk_live_...)
Body
application/json
Template build configuration
REQUIRED
REQUIRED
Base image (REQUIRED - separate from steps)
REQUIRED (MB)
Core fields - ALL REQUIRED, no defaults
Private registry support
Optional
Steps - build steps (RUN, COPY, ENV, WORKDIR, USER, CMD) Note: FROM is NOT a step, it's specified in from_image field
Update flag

