The prompt is the cheapest lever you have — no training, no infra. 'Context engineering' is the grown-up name: deciding exactly what the model sees. Descend.
⚡The prompt was perfect in the playground. In production it drifts, ignores half your rules, and returns JSON that won't parse.
LEVEL 1 — REMEMBER · the vocabulary
⚓ ANCHOR · IF YOU ALREADY KNOW
A prompt is a function call in natural language: role + task + context are the arguments, and a structured-output schema is the return type. A vague prompt is an untyped call — you get back whatever.