When updating configuration/env logic, treat it as compatibility-sensitive: preserve existing default behavior and env var formats, avoid enabling config blocks that silently change runtime semantics, and ensure config typing and dependent settings stay consistent.

Apply these rules:

Example pattern (YAML typing):

# Good: numeric port
port: '${MYSQL_PORT:-3306}'

# Avoid patterns that can cause type issues depending on templating/YAML parsing rules
# e.g., port: '3306' (string) if the consumer expects an int