Path · 9 of 17 chapters · 1 hr 57 min
Understand the mechanics
Before you cost anything, know what burns the energy. And why.
Read them in this order. The numbers are the ones from the full course: this path skips 8 chapters that do not serve the question.
- 01What happens when you send a prompt to an AI?What goes on inside an LLM when you send a prompt, and where the electricity goes at each of the six steps.Start here · 19 min read
- 02Why count tokens instead of requests?The unit that makes an AI footprint auditable, and the three token classes a single counter always gets wrong by a factor of 5 to 10.9 min read
- 03Does French cost more than English?What a language costs in tokens, why the corpus rather than the grammar decides it, and what it changes for a multilingual service.10 min read
- 04Why does an output token cost 35 times an input token?The two physical regimes of an inference, the measured coefficients behind the factor of 35, and the levers that follow from them.12 min read
- 05Why does long context cost so much?Where the cost of a long context actually sits, and why two independent providers landed on the same x2 pricing tier.11 min read · technical
- 06Why does a model's parameter count no longer tell you its cost?Read the only number that predicts inference compute, and see why MoE cuts calculation while quietly inflating the hardware you have to keep loaded.12 min read · technical
- 07Does training or inference weigh more in an AI model's footprint?Gives you the crossover threshold, the reason server fill moves it by a factor of 30, and the five circulating figures that measure five different things.17 min read · technical
- 08How much energy does an LLM's reasoning mode use?Sorts six published multipliers by scope so you stop stacking them, and shows how to measure the effort setting on your own tasks in an afternoon.13 min read
- 09Why does an AI agent use up to 1,000 times a single request?Explains the quadratic growth behind agentic cost, what prompt caching does and does not solve, and which three usage-export figures rebuild the footprint.14 min read